Chemistry 9th Edition By Zumdahl – Test Bank

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Chemistry 9th Edition By Zumdahl – Test Bank

Chapter 6: Thermochemistry

 

  1. A gas absorbs 0.0 J of heat and then performs 30.7 J of work. The change in internal energy of the gas is
A) 61.4 J
B) 30.7 J
C) –61.4 J
D) –30.7 J
E) none of these

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | energy | internal energy          MSC:            Quantitative

 

  1. What is the kinetic energy of a 1.56-kg object moving at 94.0 km/hr?
A) 5.32 ´ 102 kJ
B) 6.89 ´ 103 kJ
C) 5.32 ´ 10–4 kJ
D) 1.06 ´ 103 kJ
E) 2.04 ´ 101 kJ

 

 

ANS:   A                     PTS:    1                      DIF:    Moderate        REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | energy | kinetic energy           MSC:            Quantitative

 

  1. Which of the following statements correctly describes the signs of q and w for the following exothermic process at P = 1 atm and T = 370 K?

H2O(g) ® H2O(l)

A) q and w are negative.
B) q is positive, w is negative.
C) q is negative, w is positive.
D) q and w are both positive.
E) q and w are both zero.

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | energy | internal energy          MSC:            Conceptual

 

  1. For a particular process q = 20 kJ and w = 15 kJ. Which of the following statements is true?
A) Heat flows from the system to the surroundings.
B) The system does work on the surroundings.
C) DE = 35 kJ
D) All of the above are true.
E) None of the above are true.

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | energy | internal energy          MSC:            Conceptual

 

  1. Which of the following statements is correct?
A) The internal energy of a system increases when more work is done by the system than heat was flowing into the system.
B) The internal energy of a system decreases when work is done on the system and heat is flowing into the system.
C) The system does work on the surroundings when an ideal gas expands against a constant external pressure.
D) All statements are true.
E) All statements are false.

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | energy | internal energy          MSC:            Conceptual

 

  1. For a particular process q = –17 kJ and w = 21 kJ. Which of the following statements is false?
A) Heat flows from the system to the surroundings.
B) The system does work on the surroundings.
C) DE = +4 kJ
D) The process is exothermic.
E) None of the above is false.

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | energy | internal energy          MSC:            Conceptual

 

  1. One mole of an ideal gas is expanded from a volume of 1.00 liter to a volume of 8.93 liters against a constant external pressure of 1.00 atm. How much work (in joules) is performed on the surroundings? Ignore significant figures for this problem. (T = 300 K; 1 L·atm = 101.3 J)
A) 402 J
B) 803 J
C) 2.41 ´ 103 J
D) 905 J
E) none of these

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | thermodynamics | first law of thermodynamics  MSC:            Quantitative

 

  1. Calculate the work for the expansion of CO2 from 1.0 to 4.7 liters against a pressure of 1.0 atm at constant temperature.
A) 3.7 L·atm
B) 4.7 L·atm
C) 0 L·atm
D) –3.7 L·atm
E) –4.7 L·atm

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | thermodynamics | first law of thermodynamics  MSC:            Quantitative

 

  1. A fuel-air mixture is placed in a cylinder fitted with a piston. The original volume is 0.310-L. When the mixture is ignited, gases are produced and 935 J of energy is released. To what volume will the gases expand against a constant pressure of 635 mmHg, if all the energy released is converted to work to push the piston?
A) 10.7 L
B) 8.02 L
C) 11.4 L
D) 11.0 L
E) 1.78 L

 

 

ANS:   C                     PTS:    1                      DIF:    Moderate        REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | thermodynamics | first law of thermodynamics  MSC:            Quantitative

 

  1. Which statement is true of a process in which one mole of a gas is expanded from state A to state B?
A) When the gas expands from state A to state B, the surroundings are doing work on the system.
B) The amount of work done in the process must be the same, regardless of the path.
C) It is not possible to have more than one path for a change of state.
D) The final volume of the gas will depend on the path taken.
E) The amount of heat released in the process will depend on the path taken.

 

 

ANS:   E                     PTS:    1                      DIF:    Moderate        REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | thermodynamics | first law of thermodynamics  MSC:            Conceptual

 

  1. Calculate the work associated with the expansion of a gas from 42.0 L to 79.0 L at a constant pressure of 14.0 atm.
A) 518 L·atm
B) –518 L·atm
C) –1.11 ´ 103 L·atm
D) 588 L·atm
E) 1.11 ´ 103 L·atm

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | thermodynamics | first law of thermodynamics  MSC:            Quantitative

 

  1. Calculate the work associated with the compression of a gas from 121.0 L to 80.0 L at a constant pressure of 13.1 atm.
A) –537 L atm
B) 537 L atm
C) 3.13 L atm
D) –3.13 L atm
E) 101 L atm

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | thermodynamics | first law of thermodynamics  MSC:            Quantitative

 

  1. According to the first law of thermodynamics, the energy of the universe is constant. Does this mean that DE is always equal to zero?
A) Yes, DE = 0 at all times, which is why q = –w.
B) No, DE does not always equal zero, but this is only due to factors like friction and heat.
C) No, DE does not always equal zero because it refers to the system’s internal energy, which is affected by heat and work.
D) No, DE never equals zero because work is always being done on the system or by the system.
E) No, DE never equals zero because energy is always flowing between the system and surroundings.

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | thermodynamics | first law of thermodynamics  MSC:            Conceptual

 

Consider a gas in a 1.0 L bulb at STP that is connected via a valve to another bulb that is initially evacuated. Answer the following concerning what occurs when the valve between the two bulbs is opened.

 

  1. What is true about the value of q?
A) It is greater than zero.
B) It is equal to zero.
C) It is less than zero.
D) More information is needed.
E) None of these.

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | enthalpy

MSC:   Conceptual

 

  1. What is true about the value of w?
A) It is greater than zero.
B) It is equal to zero.
C) It is less than zero.
D) More information is needed.
E) None of these.

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | thermodynamics | first law of thermodynamics  MSC:            Conceptual

 

  1. What is true about the value of DE?
A) It is greater than zero.
B) It is equal to zero.
C) It is less than zero.
D) More information is needed.
E) None of these.

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | energy | internal energy          MSC:            Conceptual

 

  1. What is true about the value of DH?
A) It is greater than zero.
B) It is equal to zero.
C) It is less than zero.
D) More information is needed.
E) None of these.

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | enthalpy | enthalpy and internal energy                                    MSC:   Conceptual

 

  1. A property that is independent of the pathway is called an intensive property.

 

ANS:   F                      PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | thermodynamics | first law of thermodynamics  MSC:            Conceptual

 

  1. A state function does not depend on the system’s past or future.

 

ANS:   T                      PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | thermodynamics | first law of thermodynamics  MSC:            Conceptual

 

  1. When a system performs work on the surroundings, the work is reported with a negative sign.

 

ANS:   T                      PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | thermodynamics | first law of thermodynamics  MSC:            Conceptual

 

  1. In exothermic reaction, potential energy stored in chemical bonds is being converted to thermal energy via heat.

 

ANS:   T                      PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | energy | potential energy        MSC:            Conceptual

 

  1. Of energy, work, enthalpy, and heat, how many are state functions?
A) 0
B) 1
C) 2
D) 3
E) 4

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | thermodynamics | first law of thermodynamics  MSC:            Conceptual

 

  1. Which of the following properties is (are) intensive properties?
  2. mass
  3. temperature

III.  volume

  1. concentration
  2. energy
A) I, III, and V
B) II only
C) II and IV
D) III and IV
E) I and V

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | enthalpy | enthalpy change     MSC:            Conceptual

 

  1. For the reaction H2O(l) ® H2O(g) at 298 K and 1.0 atm, DH is more positive than DE by 2.5 kJ/mol. This quantity of energy can be considered to be
A) the heat flow required to maintain a constant temperature
B) the work done in pushing back the atmosphere
C) the difference in the H–O bond energy in H2O(l) compared to H2O(g)
D) the value of DH itself
E) none of these

 

 

ANS:   B                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | enthalpy | enthalpy and internal energy                                    MSC:   Conceptual

 

  1. Which one of the following statements is false?
A) The change in internal energy, DE, for a process is equal to the amount of heat absorbed at constant volume, qv.
B) The change in enthalpy, DH, for a process is equal to the amount of heat absorbed at constant pressure, qp.
C) A bomb calorimeter measures DH directly.
D) If qp for a process is negative, the process is exothermic.
E) The freezing of water is an example of an exothermic reaction.

 

 

ANS:   C                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction

MSC:   Conceptual

 

  1. C2H5OH(l) + 3O2(g) ® 2CO2(g) + 3H2O(l), DH = –1.37 ´ 103 kJ

For the combustion of ethyl alcohol as described in the above equation, which of the following is true?

  1. The reaction is exothermic.
  2. The enthalpy change would be different if gaseous water was produced.

III. The reaction is not an oxidation–reduction one.

  1. The products of the reaction occupy a larger volume than the reactants.
A) I, II
B) I, II, III
C) I, III, IV
D) III, IV
E) only I

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction

MSC:   Conceptual

 

  1. Consider the reaction:

C2H5OH(l) + 3O2(g) ® 2CO2(g) + 3H2O(l); DH = –1.37 ´ 103 kJ

Consider the following propositions:

  1. The reaction is endothermic
  2. The reaction is exothermic.

III. The enthalpy term would be different if the water formed was gaseous.

Which of these propositions is (are) true?

A) I
B) II
C) III
D) I, II
E) II, III

 

 

ANS:   E                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction

MSC:   Conceptual

 

  1. How much heat is required to raise the temperature of a 5.75-g sample of iron (specific heat = 0.450 J/g°C) from 25.0°C to 79.8°C?
A) 2.54 J
B) 315 J
C) 700 J
D) 848 J
E) 142 J

 

 

ANS:   E                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry

MSC:   Quantitative

 

  1. Two metals of equal mass with different heat capacities are subjected to the same amount of heat. Which undergoes the smallest change in temperature?
A) The metal with the higher heat capacity.
B) The metal with the lower heat capacity.
C) Both undergo the same change in temperature.
D) You need to know the initial temperatures of the metals.
E) You need to know which metals you have.

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry | heat capacity      MSC:            Conceptual

 

  1. A 32.5 g piece of aluminum (which has a molar heat capacity of 24.03 J/°C·mol) is heated to 82.4°C and dropped into a calorimeter containing water (specific heat capacity of water is 4.18 J/g°C) initially at 22.3°C. The final temperature of the water is 24.2°C. Ignoring significant figures, calculate the mass of water in the calorimeter.
A) 212 g
B) 5.72 kg
C) 6.42 g
D) 1.68 kg
E) none of these

 

 

ANS:   A                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry

MSC:   Quantitative

 

  1. A 45.9 g sample of a metal is heated to 95.2°C and then placed in a calorimeter containing 120.0 g of water (c = 4.18 J/g°C) at 21.6°C. The final temperature of the water is 24.5°C. Which metal was used?
A) Aluminum (c = 0.89 J/g°C)
B) Iron (c = 0.45 J/g°C)
C) Copper (c = 0.20 J/g°C)
D) Lead (c = 0.14 J/g°C)
E) none of these

 

 

ANS:   B                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry | specific heat       MSC:            Quantitative

 

  1. You take 295.5 g of a solid at 30.0°C and let it melt in 425 g of water. The water temperature decreases from 85.1°C to 30.0°C. Calculate the heat of fusion of this solid.
A) 160 J/g
B) 166 J/g
C) 331 J/g
D) 721 J/g
E) cannot solve without the heat capacity of the solid

 

 

ANS:   C                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry

MSC:   Quantitative

 

  1. The enthalpy of fusion of ice is 6.020 kJ/mol. The heat capacity of liquid water is 75.4 J/mol·°C. What is the smallest number of ice cubes at 0°C, each containing one mole of water, necessary to cool 500 g of liquid water initially at 20°C to 0°C?
A) 1
B) 7
C) 14
D) 15
E) 126

 

 

ANS:   B                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry

MSC:   Conceptual

 

  1. 30.0 mL of pure water at 282 K is mixed with 50.0 mL of pure water at 306 K. What is the final temperature of the mixture?
A) 294 K
B) 297 K
C) 342 K
D) 588 K
E) 24 K

 

 

ANS:   B                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry

MSC:   Quantitative

 

  1. Consider the reaction

H2(g) + O2(g) ® H2O(l)     DH° = –286 kJ

Which of the following is true?

A) The reaction is exothermic.
B) The reaction is endothermic.
C) The enthalpy of the products is less than that of the reactants.
D) Heat is absorbed by the system.
E) Both A and C are true.

 

 

ANS:   E                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | heat | heats of reaction           MSC:            Conceptual

 

  1. In the lab, you mix two solutions (each originally at the same temperature) and the temperature of the resulting solution decreases. Which of the following is true?
A) The chemical reaction is releasing energy.
B) The energy released is equal to s ´ m ´ DT.
C) The chemical reaction is absorbing energy.
D) The chemical reaction is exothermic.
E) More than one of these.

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry

MSC:   Conceptual

 

  1. What is the specific heat capacity of a metal if it requires 178.1 J to change the temperature of 15.0 g of the metal from 25.00°C to 32.00°C?
A) 0.590 J/g°C
B) 11.9 J/g°C
C) 25.4 J/g°C
D) 1.70 J/g°C
E) 283 J/g°C

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry | specific heat       MSC:            Quantitative

 

  1. A 140.0-g sample of water at 25.0°C is mixed with 111.7 g of a certain metal at 100.0°C. After thermal equilibrium is established, the (final) temperature of the mixture is 29.6°C. What is the specific heat capacity of the metal, assuming it is constant over the temperature range concerned?
A) 0.34 J/g°C
B) 0.68 J/g°C
C) 0.22 J/g°C
D) 2.9 J/g°C
E) none of these

 

 

ANS:   A                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry | specific heat       MSC:            Quantitative

 

  1. If 5.0 kJ of energy is added to a 15.5-g sample of water at 10.°C, the water is
A) boiling
B) completely vaporized
C) frozen solid
D) decomposed
E) still a liquid

 

 

ANS:   E                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry | heat capacity      MSC:            Conceptual

 

  1. Exactly 123.7 J will raise the temperature of 10.0 g of a metal from 25.0°C to 60.0°C. What is the specific heat capacity of the metal?
A) 2.83 J/g°C
B) 0.353 J/g°C
C) 24.9 J/g°C
D) 29.6 J/g°C
E) none of these

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry | specific heat       MSC:            Quantitative

 

  1. A chunk of lead at 91.6°C was added to 200.0 g of water at 15.5°C. The specific heat of lead is 0.129 J/g°C, and the specific heat of water is 4.18 J/g°C. When the temperature stabilized, the temperature of the mixture was 17.9°C. Assuming no heat was lost to the surroundings, what was the mass of lead added?
A) 1.57 kg
B) 170 g
C) 204 g
D) 211 g
E) none of these

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry | specific heat       MSC:            Quantitative

 

  1. On a cold winter day, a steel metal fence post feels colder than a wooden fence post of identical size because:
A) The specific heat capacity of steel is higher than the specific heat capacity of wood.
B) The specific heat capacity of steel is lower than the specific heat capacity of wood.
C) Steel has the ability to resist a temperature change better than wood.
D) The mass of steel is less than wood so it loses heat faster.
E) Two of the above statements are true.

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry | specific heat       MSC:            Conceptual

 

  1. What is the specific heat capacity of silver if it requires 86.3 J to raise the temperature of 15 grams of silver by 25°C?
A) 4.3 J/g°C
B) 0.23 J/g°C
C) 0.14 J/g°C
D) 0.60 J/g°C
E) none of these

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry | specific heat       MSC:            Quantitative

 

  1. A 4.4-g sample of Colorado oil shale is burned in a bomb calorimeter, which causes the temperature of the calorimeter to increase by 5.0°C. The calorimeter contains 1.00 kg of water (heat capacity of H2O = 4.184 J/g°C) and the heat capacity of the empty calorimeter is 0.10 kJ/°C. How much heat is released per gram of oil shale when it is burned?
A) 21 kJ/g
B) 42 kJ/g
C) 0 kJ/g
D) 4.9 kJ/g
E) 0.21 kJ/g

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry | measuring heats of reaction                                    MSC:   Quantitative

 

  1. If a student performs an endothermic reaction in a calorimeter, how does the calculated value of DH differ from the actual value if the heat exchanged with the calorimeter is not taken into account?
A) DHcalc would be more negative because the calorimeter always absorbs heat from the reaction.
B) DHcalc would be less negative because the calorimeter would absorb heat from the reaction.
C) DHcalc would be more positive because the reaction absorbs heat from the calorimeter.
D) DHcalc would be less positive because the reaction absorbs heat from the calorimeter.
E) DHcalc would equal the actual value because the calorimeter does not absorb heat.

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry | measuring heats of reaction                                    MSC:   Conceptual

 

  1. A bomb calorimeter has a heat capacity of 2.47 kJ/K. When a 0.109-g sample of ethylene (C2H4) was burned in this calorimeter, the temperature increased by 2.22 K. Calculate the energy of combustion for one mole of ethylene.
A) –5.29 kJ/mol
B) –50.3 kJ/mol
C) –636 kJ/mol
D) –0.269 kJ/mol
E) –1.41 ´ 103 kJ/mol

 

 

ANS:   E                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry | measuring heats of reaction                                    MSC:   Quantitative

 

  1. Consider the reaction:

 

When a 21.1-g sample of ethyl alcohol (molar mass = 46.07 g/mol) is burned, how much energy is released as heat?

A) 0.458 kJ
B) 0.627 kJ
C) 6.27 ´ 102 kJ
D) 2.89 ´ 104 kJ
E) 2.18 kJ

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | thermochemical equation | stoichiometry and heats of reaction              MSC:              Quantitative

 

  1. The DH value for the reaction  is -90.8 kJ. How much heat is released when 66.9 g Hg is reacted with oxygen?
A) 0.333 kJ
B) 6.07 ´ 103 kJ
C) 30.3 kJ
D) 90.8 kJ
E) none of these

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | thermochemical equation | stoichiometry and heats of reaction              MSC:              Quantitative

 

  1. The total volume of hydrogen gas needed to fill the Hindenburg was 2.11 ´ 108 L at 1.00 atm and 24.7°C. How much energy was evolved when it burned?

 

A) 8.64 ´ 106 kJ
B) 2.98 ´ 1010 kJ
C) 3.02 ´ 104 kJ
D) 2.47 ´ 109 kJ
E) 4.94 ´ 109 kJ

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | thermochemical equation | stoichiometry and heats of reaction              MSC:              Quantitative

 

  1. CH4(g) + 4Cl2(g) ® CCl4(g) + 4HCl(g), DH = –434 kJ

Based on the above reaction, what energy change occurs when 1.2 moles of methane (CH4) reacts?

A) 5.2 ´ 105 J are released.
B) 5.2 ´ 105 J are absorbed.
C) 3.6 ´ 105 J are released.
D) 3.6 ´ 105 J are absorbed.
E) 4.4 ´ 105 J are released.

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | thermochemical equation | stoichiometry and heats of reaction              MSC:              Quantitative

 

  1. Given the equation S(s) + O2(g) ® SO2(g), DH = –296 kJ, which of the following statement(s) is (are) true?
  2. The reaction is exothermic.
  3. When 0.500 mole sulfur is reacted, 148 kJ of energy is released.

III.  When 32.0 g of sulfur are burned, 2.96 ´ 105 J of energy is released.

A) All are true.
B) None is true.
C) I and II are true.
D) I and III are true.
E) Only II is true.

 

 

ANS:   A                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | thermochemical equation | stoichiometry and heats of reaction              MSC:              Conceptual

 

  1. When 0.236 mol of a weak base (A) is reacted with excess HCl, 6.91 kJ of energy is released as heat. What is DH for this reaction per mole of A consumed?
A) –34.2 kJ
B) –59.4 kJ
C) –29.3 kJ
D) 34.2 kJ
E) 29.3 kJ

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | thermochemical equation | stoichiometry and heats of reaction              MSC:              Quantitative

 

  1. What is the enthalpy change when 49.4 mL of 0.430 M sulfuric acid reacts with 23.3 mL of 0.309 M potassium hydroxide?
H2SO4(aq) + 2KOH(aq) ® K2SO4(aq) + 2H2O(l) DH° = –111.6 kJ/mol

 

A) –0.402 kJ
B) –3.17 kJ
C) –2.37 kJ
D) –0.803 kJ
E) –112 kJ

 

 

ANS:   A                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | enthalpy | enthalpy change     MSC:            Quantitative

 

  1. How much heat is liberated at constant pressure when 2.35 g of potassium metal reacts with 5.68 mL of liquid iodine monochloride (d = 3.24 g/mL)?
2K(s) + ICl(l) ® KCl(s) + KI(s) DH° = –740.71 kJ/mol

 

A) 2.22 ´ 103 kJ
B) 8.40 ´ 101 kJ
C) 1.28 ´ 102 kJ
D) 2.23 ´ 101 kJ
E) 7.41 ´ 102 kJ

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | enthalpy | enthalpy change     MSC:            Quantitative

 

  1. Consider the following specific heats of metals.
Metal Specific Heat
Zinc 0.387 J/(g°C)
Magnesium 1.02 J/(g°C)
Iron 0.450 J/(g°C)
Silver 0.237 J/(g°C)
Lead 0.127 J/(g°C)

If the same amount of heat is added to 25.0 g of each of the metals, which are all at the same initial temperature, which metal will have the highest temperature?

A) Zinc
B) Magnesium
C) Iron
D) Silver
E) Lead

 

 

ANS:   E                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry | specific heat       MSC:            Conceptual

 

  1. The heat of combustion of benzene, C6H6, is –41.74 kJ/g. Combustion of 2.82 g of benzene causes a temperature rise of 3.29°C in a certain bomb calorimeter. What is the heat capacity of this bomb calorimeter?
A) 387 kJ/°C
B) 35.8 kJ/°C
C) 0.222 kJ/°C
D) 5.96 kJ/°C
E) 118 kJ/°C

 

 

ANS:   B                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry | heat capacity      MSC:            Quantitative

 

  1. The specific heat capacities of metals are relatively low.

 

ANS:   T                      PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry | specific heat       MSC:            Conceptual

 

  1. The change in enthalpy can always be thought of as equal to energy flow as heat.

 

ANS:   F                      PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | enthalpy

MSC:   Conceptual

 

  1. Which of the following statements is/are true?
I. q (heat) is a state function because DH is a state function and q = DH.
II. When 50.0 g of aluminum at 20.0°C is placed in 50.0 mL of water at 30.0°C, the H2O will undergo a smaller temperature change than the aluminum. (The density of H2O = 1.0 g/mL, specific heat capacity of H2O = 4.18 J/g°C, specific heat capacity of aluminum = 0.89 J/g°C)
III. When a gas is compressed, the work is negative since the surroundings are doing work on the system and energy flows out of the system.
IV. For the reaction (at constant pressure) 2N2(g) + 5O2(g) ® 2N2O5(g), the change in enthalpy is the same whether the reaction takes place in one step or in a series of steps.

 

A) I, II, IV
B) II, III
C) II, III, IV
D) II, IV
E) All of the above statements are true.

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    6.3

KEY:   Chemistry | general chemistry | thermochemistry                  MSC:   Conceptual

 

  1. Consider the following processes:
2A ® (1/2)B + C DH1 = 5 kJ/mol
(3/2)B + 4C ® 2A + C + 3D DH2 = –15 kJ/mol
E + 4A ® C DH3 = 10 kJ/mol

Calculate DH for:    C ® E + 3D

A) 0 kJ/mol
B) 10 kJ/mol
C) –10 kJ/mol
D) –20 kJ/mol
E) 20 kJ/mol

 

 

ANS:   C                     PTS:    1                      DIF:    Moderate        REF:    6.3

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | Hess’s law

MSC:   Quantitative

 

  1. Consider the following processes:
DH (kJ/mol)
3B ® 2C + D  –125.
(1/2)A ® B   150
E + A ® D   350

Calculate DH for: B ® E + 2C

A) 325 kJ/mol
B) 525 kJ/mol
C) –175 kJ/mol
D) –325 kJ/mol
E) none of these

 

 

ANS:   C                     PTS:    1                      DIF:    Moderate        REF:    6.3

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | Hess’s law

MSC:   Quantitative

 

  1. Consider the following numbered processes:
 1. A ® 2B
 2. B ® C + D
 3. E ® 2D

DH for the process A ® 2C + E is

A) DH1 + DH2 + DH3
B) DH1 + DH2
C) DH1 + DH2 – DH3
D) DH1 + 2DH2 – DH3
E) DH1 + 2DH2 + DH3

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    6.3

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | Hess’s law

MSC:   Conceptual

 

  1. At 25°C, the following heats of reaction are known:
DH (kJ/mol)
2ClF + O2 ® Cl2O + F2O 167.4
2ClF3 + 2O2 ® Cl2O + 3F2O 341.4
2F2 + O2 ® 2F2O –43.4

At the same temperature, calculate DH for the reaction: ClF + F2 ® ClF3

A) –217.5 kJ/mol
B) –130.2 kJ/mol
C) +217.5 kJ/mol
D) –108.7 kJ/mol
E) none of these

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    6.3

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | Hess’s law

MSC:   Quantitative

 

  1. Calculate DH° for the reaction C4H4(g) + 2H2(g) ® C4H8(g), using the following data:

DH°combustion for C4H4(g) = –2341 kJ/mol

DH°combustion for H2(g) = –286 kJ/mol

DH°combustion for C4H8(g) = –2755 kJ/mol

A) –128 kJ
B) –158 kJ
C) 128 kJ
D) 158 kJ
E) none of these

 

 

ANS:   B                     PTS:    1                      DIF:    Difficult          REF:    6.3

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | Hess’s law

MSC:   Quantitative

 

  1. Given the heats of the following reactions:
DH°(kJ)
I. P4(s) + 6Cl2(g) ® 4PCl3(g) –1225.6
II. P4(s) + 5O2(g) ® P4O10(s) –2967.3
III. PCl3(g) + Cl2(g) ® PCl5(g)  –84.2
IV. PCl3(g) + O2(g) ® Cl3PO(g) –285.7

Calculate the value of DH° for the reaction below:

P4O10(s) + 6PCl5(g) ® 10Cl3PO(g)

A) –110.5 kJ
B) –610.1 kJ
C) –2682.2 kJ
D) –7555.0 kJ
E) None of these is within 5% of the correct answer.

 

 

ANS:   B                     PTS:    1                      DIF:    Moderate        REF:    6.3

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | Hess’s law

MSC:   Quantitative

 

  1. Using the following thermochemical data:
2Cr(s) + 6HF(g) ® 2CrF3(s) + 3H2(g) DH° = –691.4 kJ/mol
2Cr(s) + 6HCl(g) ® 2CrCl3(s) + 3H2(g) DH° = –559.2 kJ/mol

calculate DH° for the following reaction:

CrF3(s) + 3HCl(g) ® CrCl3(s) + 3HF(g)

A) –1250.6 kJ/mol
B) 132.2 kJ/mol
C) 66.1 kJ/mol
D) 264.4 kJ/mol
E) –625.3 kJ/mol

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    6.3

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | Hess’s law

MSC:   Quantitative

 

  1. Using the following thermochemical data, calculate DHf° of Tm2O3(s).
2TmCl3(s) + 3H2O(l) ® Tm2O3(s) + 6HCl(g) DH° = 388.1 kJ/mol
2Tm(s) + 3Cl2(g) ® 2TmCl3(s) DH° = –1973.2 kJ/mol
4HCl(g) + O2(g) ® 2Cl2(g) + 2H2O(l) DH° = –202.4 kJ/mol

 

A) –1888.7 kJ/mol
B) –1787.5 kJ/mol
C) 2563.7 kJ/mol
D) –2158.9 kJ/mol
E) 1382.7 kJ/mol

 

 

ANS:   A                     PTS:    1                      DIF:    Moderate        REF:    6.3

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | Hess’s law

MSC:   Quantitative

 

  1. The heat of formation of Fe2O3(s) is –826.0 kJ/mol. Calculate the heat of the reaction  when a 53.99-g sample of iron is reacted.
A) –199.6 kJ
B) –399.2 kJ
C) –798.5 kJ
D) –1597 kJ
E) –2.230 ´ 104 kJ

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    6.4

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | standard enthalpies of formation                   MSC:              Quantitative

 

  1. Which of the following does not have a standard enthalpy of formation equal to zero at 25°C and 1.0 atm?
A) F2(g)
B) Al(s)
C) H2O(l)
D) H2(g)
E) They all have a standard enthalpy equal to zero.

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    6.4

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | standard enthalpies of formation                   MSC:              Conceptual

 

  1. Given the following two reactions at 298 K and 1 atm, which of the statements is true?
1. N2(g) + O2(g) ® 2NO(g) DH1
2. NO(g) + O2(g) ® NO2(g) DH2

 

A) DHf° for NO2(g) = DH2
B) DHf° for NO(g) = DH1
C) DHf° = DH2
D) DHf° for NO2(g) = DH2 + DH1
E) none of these

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    6.4

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | standard enthalpies of formation                   MSC:              Conceptual

 

  1. Given:
Cu2O(s) + O2(g) ® 2CuO(s) DH° = –144 kJ
Cu2O(s) ® Cu(s) + CuO(s) DH° = +11 kJ

Calculate the standard enthalpy of formation of CuO(s).

A) –166 kJ
B) –299 kJ
C) +299 kJ
D) +155 kJ
E) –155 kJ

 

 

ANS:   E                     PTS:    1                      DIF:    Moderate        REF:    6.4

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | standard enthalpies of formation                   MSC:              Quantitative

 

  1. Using the following data, calculate the standard heat of formation of the compound ICl in kJ/mol:
DH° (kJ/mol)
Cl2(g) ® 2Cl(g) 242.3
I2(g) ® 2I(g) 151.0
ICl(g) ® I(g) + Cl(g) 211.3
I2(s) ® I2(g) 62.8

 

A) –211 kJ/mol
B) –14.6 kJ/mol
C) 16.8 kJ/mol
D) 245 kJ/mol
E) 439 kJ/mol

 

 

ANS:   C                     PTS:    1                      DIF:    Moderate        REF:    6.4

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | standard enthalpies of formation                   MSC:              Quantitative

 

  1. The heat combustion of acetylene, C2H2(g), at 25°C is –1299 kJ/mol. At this temperature, DHf° values for CO2(g) and H2O(l) are –393 and –286 kJ/mol, respectively. Calculate DHf° for acetylene.
A) 2376 kJ/mol
B) 625 kJ/mol
C) 227 kJ/mol
D) –625 kJ/mol
E) –227 kJ/mol

 

 

ANS:   C                     PTS:    1                      DIF:    Moderate        REF:    6.4

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | standard enthalpies of formation                   MSC:              Quantitative

 

  1. Choose the correct equation for the standard enthalpy of formation of CO(g), where DHf° for CO = –110.5 kJ/mol (gr indicates graphite).
A) 2C(gr) + O2(g) ® 2CO(g),       DH° = –110.5 kJ
B) C(gr) + O(g) ® CO(g),            DH° = –110.5 kJ
C) C(gr) + O2(g) ® CO(g),       DH° = –110.5 kJ
D) C(gr) + CO2(g) ® 2CO(g),      DH° = –110.5 kJ
E) CO(g) ® C(gr) + O(g),            DH° = –110.5 kJ

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    6.4

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | standard enthalpies of formation                   MSC:              Conceptual

 

  1. For the reaction:

AgI(s) + Br2(g) ® AgBr(s) + I2(s), DH° = –54.0 kJ

DHf° for AgBr(s) = –100.4 kJ/mol

DHf° for Br2(g) = +30.9 kJ/mol

The value of DHf° for AgI(s) is:

A) –123.5 kJ/mol
B) +77.3 kJ/mol
C) +61.8 kJ/mol
D) –77.3 kJ/mol
E) –61.8 kJ/mol

 

 

ANS:   E                     PTS:    1                      DIF:    Easy                REF:    6.4

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | standard enthalpies of formation                   MSC:              Quantitative

 

  1. Using the information below, calculate DHf° for PbO(s)

PbO(s) + CO(g) ® Pb(s) + CO2(g)     DH° = –131.4 kJ

DHf° for CO2(g) = –393.5 kJ/mol

DHf° for CO(g) = –110.5 kJ/mol

A) –151.6 kJ/mol
B) –283.0 kJ/mol
C) +283.0 kJ/mol
D) –372.6 kJ/mol
E) +252.1 kJ/mol

 

 

ANS:   A                     PTS:    1                      DIF:    Moderate        REF:    6.4

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | standard enthalpies of formation                   MSC:              Quantitative

 

  1. For which of the following reaction(s) is the enthalpy change for the reaction not equal to DHf° of the product?
I. 2H(g) ® H2(g)
II. H2(g) + O2(g) ® H2O2(l)
III. H2O(l) + O(g) ® H2O2(l)

 

A) I
B) II
C) III
D) I and III
E) II and III

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    6.4

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | standard enthalpies of formation                   MSC:              Conceptual

 

  1. Consider the reaction:

2ClF3(g) + 2NH3(g) ® N2(g) + 6HF(g) + Cl2(g)

When calculating the DH°rxn, why is the DHf° for N2 not important?

A) Because nitrogen is in its standard elemental state and no energy is needed for this product to exist.
B) Because any element or compound in the gaseous state requires a negligible amount of energy to exist.
C) Because the products are not included when calculating DH°rxn.
D) Because nitrogen is in its elemental state and does not contribute to the reaction itself.
E) Two of the above statements explain why N2 is not important when calculating DH°rxn.

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    6.4

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | standard enthalpies of formation                   MSC:              Conceptual

 

  1. The following statements concerning petroleum are all true except:
A) It is a thick, dark liquid composed mostly of hydrocarbons.
B) It must be separated into fractions (by boiling) in order to be used efficiently.
C) Some of the commercial uses of petroleum fractions include gasoline and kerosene.
D) It was probably formed from the remains of ancient marine organisms.
E) All of its hydrocarbon chains contain the same number of carbon atoms.

 

 

ANS:   E                     PTS:    1                      DIF:    Easy                REF:    6.5

KEY:   Chemistry | general chemistry | thermochemistry                  MSC:   Conceptual

 

  1. This fossil fuel was formed from the remains of plants that were buried and exposed to high pressure and heat over time.
A) coal
B) natural gas
C) diesel fuel
D) propane
E) gasoline

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    6.5

KEY:   Chemistry | general chemistry | thermochemistry                  MSC:   Conceptual

 

  1. The coal with the highest energy available per unit burned is
A) Lignite.
B) Subbituminous.
C) Bituminous.
D) Anthracite.
E) They are equal in energy value.

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    6.5

KEY:   Chemistry | general chemistry | thermochemistry                  MSC:   Conceptual

 

  1. All of the following statements about the greenhouse effect are true except:
A) It occurs only on earth.
B) The molecules H2O and CO2 play an important role in retaining the atmosphere’s heat.
C) Low humidity allows efficient radiation of heat back into space.
D) The carbon dioxide content of the atmosphere is quite stable.
E) A and D

 

 

ANS:   E                     PTS:    1                      DIF:    Moderate        REF:    6.5

KEY:   Chemistry | general chemistry | thermochemistry                  MSC:   Conceptual

 

  1. Which of the following is both a greenhouse gas and a fuel?
A) carbon dioxide
B) coal
C) freon
D) methane
E) nitrogen

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    6.5

KEY:   Chemistry | general chemistry | thermochemistry                  MSC:   Conceptual

 

  1. One of the main advantages of hydrogen as a fuel is that:
A) The only product of hydrogen combustion is water.
B) It exists as a free gas.
C) It can be economically supplied by the world’s oceans.
D) Plants can economically produce the hydrogen needed.
E) It contains a large amount of energy per unit volume of hydrogen gas.

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    6.6

KEY:   Chemistry | general chemistry | thermochemistry                  MSC:   Conceptual

 

  1. Which of the following is not being considered as an energy source for the future?
A) ethanol
B) methanol
C) seed oil
D) shale oil
E) carbon dioxide

 

 

ANS:   E                     PTS:    1                      DIF:    Easy                REF:    6.6

KEY:   Chemistry | general chemistry | thermochemistry                  MSC:   Conceptual

 

  1. The combustion of hydrogen gas releases 286 kJ per mol of hydrogen. If 13.0 L of hydrogen at STP was burned to produce electricity, how long would it power a 100-watt (W) light bulb? Assume no energy is lost to the surroundings. (1 W = 1 J/s)
A) 27.7 min
B) 1.92 days
C) 1.66 hr
D) 10.3 hr
E) 4.61 hr

 

 

ANS:   A                     PTS:    1                      DIF:    Moderate        REF:    6.6

KEY:   Chemistry | general chemistry | thermochemistry                  MSC:   Quantitative

 

  1. The __________ of a system is the sum of the kinetic and potential energies of all the particles in the system.

 

ANS:

internal energy

 

PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | energy | internal energy          MSC:            Conceptual

 

  1. __________ involves the transfer of energy between two objects due to a temperature difference.

 

ANS:

Heat

 

PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | heat

MSC:   Conceptual

 

  1. Consider the reaction:

N2(g) + 3H2(g) ® 2NH3(g)

Assuming this reaction takes place in an elastic balloon with an atmospheric pressure of 1.0 atm, and that you have a stoichiometric mixture of nitrogen and hydrogen, draw a microscopic diagram before and after the reaction occurs. See the example below to assist you.

ABC2(g) ® AB(g) + C2(g)           (could be drawn as)

In addition, explain whether w (the work done) is positive, negative, or zero.

 

ANS:

Work (w) will be positive since the surroundings are doing work on the system. The balanced reaction has fewer moles of product gases than moles of reactant gases, so the volume will get smaller (DV is negative) and the surroundings do compression work on the system.

See Sec. 6.1 of Zumdahl, Chemistry.

 

PTS:    1                      DIF:    Moderate        REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | thermodynamics | first law of thermodynamics  MSC:            Conceptual

 

  1. Consider the following reaction:

2Al(s) + 3Cl2(g) ® 2AlCl3(s);    DH = –1390.81 kJ

  1. a) Is the reaction exothermic or endothermic?
  2. b) How much heat is produced/required when 10.0 g AlCl3
  3. c) How many grams of Al are required to absorb/evolve 1.00 kJ of energy?

 

ANS:

  1. a) Exothermic; b) 52.2 kJ; c) 0.0388 g Al

 

See Sec. 6.2 of Zumdahl, Chemistry.

  1. a) Exothermicity is apparent from the negative DH.
  2. b) 10.0 g * (1 mol AlCl3/133.33 g) * (-1390.81 kJ/2 mol AlCl3) = -52.2 kJ = 52.2 kJ produced
  3. c) 1.00 kJ * (2 mol Al/1390.81 kJ) * (26.98 g /mol Al) = 0.0388 g Al

 

PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction

MSC:   Quantitative

 

To carry out the reaction N2 + 2O2 ® 2NO2 requires 67.7 kJ.

To carry out the reaction N2 + 2O2 ® N2O4 requires 9.7 kJ.

Consider the reaction 2NO2 ® N2O4.

 

  1. How much energy (absolute value) is involved in the reaction 2NO2 ® N2O4?

 

ANS:

58.0 kJ

 

Apply Hess’s law, see Sec. 6.3 of Zumdahl Chemistry.

2NO2 ® N2 + 2O2    DH = –67.7 kJ

N2 + 2O2 ® N2O4    DH =  9.7 kJ

–67.7 kJ + 9.7 kJ = –58.0 kJ

 

PTS:    1                      DIF:    Easy                REF:    6.3

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | Hess’s law

MSC:   Quantitative

 

  1. Is the reaction endothermic or exothermic?

 

ANS:

exothermic

 

PTS:    1                      DIF:    Easy                REF:    6.3

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | heat | heats of reaction           MSC:            Conceptual

 

  1. Consider the following data:
DH° (kJ)
Ca(s) + 2C(graphite) ® CaC2(s) –62.8
Ca(s) + O2(g) ® CaO(s) –635.5
CaO(s) + H2O(l) ® Ca(OH)2(aq) –653.1
C2H2(g) + O2(g) ® 2CO2(g) + H2O(l) –1300
C(graphite) + O2(g) ® CO2(g) –393.51

Use Hess’ law to find the change in enthalpy at 25°C for the following equation:

CaC2(s) + 2H2O(l) ® Ca(OH)2(aq) + C2H2(g)

 

ANS:

–713 kJ

 

See Sec. 6.3 of Zumdahl Chemistry.

DH° (kJ)
CaC2(s) ® 2C(graphite) + Ca(s) +62.8
Ca(s) + O2(g) ® CaO(s) –635.5
CaO(s) + H2O(l) ® Ca(OH)2(aq) –653.1
2CO2(g) + H2O(l) ® C2H2(g) + O2(g) +1300
2C(graphite) + 2O2(g) ® 2CO2(g) –787.02
                                                              total –713 kJ

 

 

PTS:    1                      DIF:    Moderate        REF:    6.3

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | Hess’s law

MSC:   Quantitative

 

  1. Consider the following standard heats of formation:

P4O10(s) = –3110 kJ/mol

H2O(l) = –286 kJ/mol

H3PO4(s) = –1279 kJ/mol

Calculate the change in enthalpy for the following process:

P4O10(s) + 6H2O(l) ® 4H3PO4(s)

 

ANS:

–290 kJ

 

See Sec. 6.4 of Zumdahl Chemistry.

4(–1279) – [–3110 + 6(–286)] = –5116 + 3110 + 1716 = –290

 

PTS:    1                      DIF:    Moderate        REF:    6.4

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | standard enthalpies of formation                   MSC:              Quantitative

 

  1. Acetylene (C2H2) and butane (C4H10) are gaseous fuels. Determine the ratio of energy available from the combustion of a given volume of acetylene to butane at the same temperature and pressure using the following data:

The change in enthalpy of combustion for C2H2(g) = –49.9 kJ/g.

The change in enthalpy of combustion for C4H10(g) = –49.5 kJ/g.

 

ANS:

About 2.21 times the volume of acetylene is needed to furnish the same energy as a given volume of butane.

 

For stoichiometry of thermochemical processes, see Sec. 6.2 of Zumdahl Chemistry.

At the same temperature and pressure, equal volumes will contain equal number of moles of gas.

1 mol C2H2 * 26.03 g/mol * –49.9 kJ/g = –1299 kJ

1 mol C4H10 * 58.12 g/mol * –49.5 kJ/g = –2877 kJ

–2877 kJ/-1299 kJ = 2.21

 

PTS:    1                      DIF:    Difficult          REF:    6.6

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | thermochemical equation | stoichiometry and heats of reaction              MSC:              Quantitative

 

  1. A gas absorbs 188 J of heat and then performs 310 J of work. The change in internal energy of the gas is
A) 498 J
B) 122 J
C) –122 J
D) –498 J
E) none of these

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | energy | internal energy          MSC:            Quantitative

 

  1. A gas absorbs 825 J of heat and then has 841 J of work done upon it. The change in internal energy of the gas is
A) 1666 J
B) 16 J
C) –16 J
D) –1666 J
E) none of these

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | energy | internal energy          MSC:            Quantitative

 

  1. A gas delivers 659 J of heat and then has 636 J of work done upon it. The change in internal energy of the gas is
A) 1295 J
B) –23 J
C) 23 J
D) –1295 J
E) none of these

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | energy | internal energy          MSC:            Quantitative

 

  1. A gas delivers 816 J of heat and then performs 495 J of work. The change in internal energy of the gas is
A) 1311 J
B) –321 J
C) 321 J
D) –1311 J
E) none of these

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    6.1

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | energy | internal energy          MSC:            Quantitative

 

  1. For the complete combustion of 1.000 mole of methane gas at 298 K and 1 atm pressure, DH° = -890.4 kJ/mol.  What will be the heat released when 1.85 g of methane is combusted under these conditions?
A) –103 kJ
B) 103 kJ
C) –7701 kJ
D) 7701 kJ
E) none of these

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | thermochemical equation | stoichiometry and heats of reaction              MSC:              Quantitative

 

  1. For the complete combustion of 1.000 mole of ethane gas at 298 K and 1 atm pressure, DH° = -1560 kJ/mol.  What will be the heat released when 4.42 g of ethane is combusted under these conditions?
A) –230 kJ
B) 230 kJ
C) 10588 kJ
D) –10588 kJ
E) none of these

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | thermochemical equation | stoichiometry and heats of reaction              MSC:              Quantitative

 

  1. For the complete combustion of 1.000 mole of propane gas at 298 K and 1 atm pressure, DH° = -2220 kJ/mol.  What will be the heat released when 4.13 g of propane is combusted under these conditions?
A) –208 kJ
B) 208 kJ
C) 23651 kJ
D) –23651 kJ
E) none of these

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | thermochemical equation | stoichiometry and heats of reaction              MSC:              Quantitative

 

  1. For the complete combustion of 1.000 mole of butane gas at 298 K and 1 atm pressure, DH° = -2877 kJ/mol.  What will be the heat released when 2.43 g of butane is combusted under these conditions?
A) –121 kJ
B) 121 kJ
C) 68669 kJ
D) –68669 kJ
E) none of these

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | thermochemical equation | stoichiometry and heats of reaction              MSC:              Quantitative

 

  1. A 36.2 g piece of metal is heated to 81°C and dropped into a calorimeter containing 50.0 g of  water (specific heat capacity of water is 4.18 J/g°C) initially at 21.7°C. The empty calorimeter has a heat capacity of 125 J/K.  The final temperature of the water is 29.7°C. Ignoring significant figures, calculate the specific heat of the metal..
A) 1.439 J/gK
B) 0.900 J/gK
C) 0.360 J/gK
D) 0.968 J/gK
E) none of these

 

 

ANS:   A                     PTS:    1                      DIF:    Moderate        REF:    6.2

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | calorimetry

MSC:   Quantitative

 

  1. Nitric acid, HNO3, was first prepared 1200 years ago by heating naturally occurring sodium nitrate (called saltpeter) with sulfuric acid to produce sodium bisulfate and collecting the vapors of HNO3 produced.  Calculate DH°rxn for this reaction.  DH°f[NaNO3(s)] = -467.8 kJ/mol; DH°f[NaHSO4(s)] = -1125.5 kJ/mol; DH°f[H2SO4(l)] = -814.0 kJ/mol; DH°f[HNO3(g)] = -135.1 kJ/mol.

 

NaNO3(s)  +  H2SO4(l)  =>   NaHSO4(s) + HNO3(g)

A) -644.2 kJ D) 644.2 kJ
B) -21.2 kJ E) -1606.8 kJ
C) 21.2 kJ

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    6.4

KEY:   Chemistry | general chemistry | thermochemistry | heats of reaction | standard enthalpies of formation                   MSC:              Quantitative

 

Chapter 7: Atomic Structure and Periodicity

 

  1. When ignited, a uranium compound burns with a green flame. The wavelength of the light given off by this flame is greater than that of
A) red light
B) infrared light
C) radio waves
D) ultraviolet light
E) gamma rays

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    7.1

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Conceptual

 

  1. Which form of electromagnetic radiation has the longest wavelengths?
A) gamma rays
B) microwaves
C) radio waves
D) infrared radiation
E) x-rays

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.1

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Conceptual

 

  1. Which of the following frequencies corresponds to light with the longest wavelength?
A) 3.00 ´ 1013 s–1
B) 4.12 ´ 105 s–1
C) 8.50 ´ 1020 s–1
D) 9.12 ´ 1012 s–1
E) 3.20 ´ 109 s–1

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.1

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Conceptual

 

  1. Which of the following are incorrectly paired?
A) wavelength – l
B) frequency – n
C) speed of light – c
D) hertz – s–1
E) x-rays – shortest wavelength

 

 

ANS:   E                     PTS:    1                      DIF:    Easy                REF:    7.1

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Conceptual

 

  1. When a strontium salt is ignited, it burns with a red flame. The frequency of the light given off by this flame is greater than
A) yellow light
B) infrared light
C) ultraviolet light
D) radio waves
E) x-rays

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.1

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Conceptual

 

  1. A line in the spectrum of atomic mercury has a wavelength of 254 nm. When mercury emits a photon of light at this wavelength, the frequency of this light is
A) 8.47 ´ 10–16 s–1
B) 7.82 ´ 10–19 s–1
C) 1.18 ´ 1015 s–1
D) 76.1 s–1
E) none of these

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.1

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Quantitative

 

  1. What is the wavelength of a photon of red light (in nm) whose frequency is 4.55 ´ 1014 Hz?
A) 659 nm
B) 1.52 ´ 106 nm
C) 152 nm
D) 455 nm
E) none of these

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.1

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Quantitative

 

  1. The SI unit for frequency is cycles per second.

 

ANS:   F                      PTS:    1                      DIF:    Easy                REF:    7.1

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Conceptual

 

  1. Green light can have a wavelength of 543 nm. The energy of a photon of this light is
A) 1.08 ´ 10–31 J
B) 5.43 ´ 10–7 J
C) 3.66 ´ 10–19 J
D) 5.52 ´ 1014 J
E) 2.73 ´ 1018 J

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.2

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Quantitative

 

  1. Consider an atom traveling at 1% of the speed of light. The de Broglie wavelength is found to be 1.46 ´ 10–3 pm. Which element is this?
A) Be
B) Zr
C) Kr
D) Fe
E) P

 

 

ANS:   B                     PTS:    1                      DIF:    Moderate        REF:    7.2

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | de Broglie relation     MSC:            Quantitative

 

  1. Which one of the following types of radiation has the shortest wavelength, the greatest energy, and the highest frequency?
A) Ultraviolet radiation.
B) Infrared radiation.
C) Visible red light.
D) Visible blue light.
E) None, because short wavelength is associated with low energy and low frequency, not high energy and high frequency.

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.2

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Conceptual

 

  1. What is the energy of a photon of blue light that has a wavelength of 453 nm?
A) 4.53 ´ 10–7 J
B) 4.39 ´ 10–19 J
C) 6.62 ´ 1014 J
D) 9.00 ´ 10–32 J
E) 2.28 ´ 1018 J

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.2

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Quantitative

 

  1. How many of the following is/are incorrect?
  2. The importance of the equation E = mc2 is that energy has mass.
  3. Electromagnetic radiation can be thought of as a stream of particles called photons.

iii. Electromagnetic radiation exhibits wave properties.

  1. Energy can only occur in discrete units called quanta.
A) 0
B) 1
C) 2
D) 3
E) 4

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.2

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Conceptual

 

From the following list of observations, choose the one that most clearly supports the following conclusion:

 a) emission spectrum of hydrogen
 b) the photoelectric effect
 c) scattering of alpha particles by metal foil
 d) diffraction
 e) cathode “rays”

 

 

  1. Electrons have wave properties.
A) observation a
B) observation b
C) observation c
D) observation d
E) observation e

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    7.2

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics

MSC:   Conceptual

 

  1. Electromagnetic radiation has wave characteristics.
A) observation a
B) observation b
C) observation c
D) observation d
E) observation e

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    7.2

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Conceptual

 

  1. Electrons in atoms have quantized energies.
A) observation a
B) observation b
C) observation c
D) observation d
E) observation e

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.3

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum effects and photons            MSC:              Conceptual

 

  1. Spacing between atoms in a crystal is on the same order as the de Broglie wavelength of accelerated electrons.
A) observation a
B) observation b
C) observation c
D) observation d
E) observation e

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    7.2

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | de Broglie relation     MSC:   Conceptual

 

  1. Diffraction results when light is scattered from a regular array of points or lines.

 

ANS:   T                      PTS:    1                      DIF:    Easy                REF:    7.2

KEY:   Chemistry | general chemistry | atomic theory | light             MSC:   Conceptual

 

  1. All matter exhibits either particulate or wave properties exclusively.

 

ANS:   F                      PTS:    1                      DIF:    Easy                REF:    7.2

KEY:   Chemistry | general chemistry | atomic theory | light             MSC:   Conceptual

 

  1. The four lines observed in the visible emission spectrum of hydrogen tell us that:
A) The hydrogen molecules they came from have the formula H4.
B) We could observe more lines if we had a stronger prism.
C) There are four electrons in an excited hydrogen atom.
D) Only certain energies are allowed for the electron in a hydrogen atom.
E) The spectrum is continuous.

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    7.3

KEY:   Chemistry | general chemistry | atomic theory | light | Bohr theory | atomic line spectra        MSC:   Conceptual

 

  1. In an investigation of the electronic absorption spectrum of a particular element, it is found that a photon having l = 500 nm provides just enough energy to promote an electron from the second quantum level to the third. From this information, we can deduce
A) the energy of the n = 2 level
B) the energy of the n = 3 level
C) the sum of the energies of n = 2 and n = 3
D) the difference in energies between n = 2 and n = 3
E) all of these

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    7.4

KEY:   Chemistry | general chemistry | atomic theory | light | Bohr theory

MSC:   Conceptual

 

Consider the following portion of the energy-level diagram for hydrogen:

n = 4 –0.1361 ´ 10–18 J
n = 3 –0.2420 ´ 10–18 J
n = 2 –0.5445 ´ 10–18 J
n = 1 –2.178 ´ 10–18 J

 

 

  1. For which of the following transitions does the light emitted have the longest wavelength?
A) n = 4 to n = 3
B) n = 4 to n = 2
C) n = 4 to n = 1
D) n = 3 to n = 2
E) n = 2 to n = 1

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.4

KEY:   Chemistry | general chemistry | atomic theory | light | Bohr theory | atomic line spectra        MSC:   Conceptual

 

  1. In the hydrogen spectrum, what is the wavelength of light associated with the n = 3 to n = 1 electron transition?
A) 3.97 ´ 10–25 nm
B) 8.21 ´ 102 nm
C) 9.75 ´ 106 cm
D) 1.94 ´ 10–18 m
E) 1.03 ´ 10–7 m

 

 

ANS:   E                     PTS:    1                      DIF:    Moderate        REF:    7.4

KEY:   Chemistry | general chemistry | atomic theory | light | Bohr theory | atomic line spectra        MSC:            Quantitative

 

  1. The wavelength of light associated with the n = 2 to n = 1 electron transition in the hydrogen spectrum is 1.216 ´ 10–7 m. By what coefficient should this wavelength be multiplied to obtain the wavelength associated with the same electron transition in the Li2+ ion?
A) 1/9
B) 1/7
C) 1/4
D) 1/3
E) 1

 

 

ANS:   A                     PTS:    1                      DIF:    Difficult          REF:    7.4

KEY:   Chemistry | general chemistry | atomic theory | light | Bohr theory | atomic line spectra        MSC:   Conceptual

 

  1. When a hydrogen electron makes a transition from n = 3 to n = 1, which of the following statements is true?
I. Energy is emitted.
II. Energy is absorbed.
III. The electron loses energy.
IV. The electron gains energy.
V. The electron cannot make this transition.

 

A) I, IV
B) I, III
C) II, III
D) II, IV
E) V

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.4

KEY:   Chemistry | general chemistry | atomic theory | light | Bohr theory | atomic line spectra        MSC:   Conceptual

 

  1. What is the wavelength of light that is emitted when an excited electron in the hydrogen atom falls from n = 5 to n = 1?
A) 1.05 ´ 107 m
B) 9.50 ´ 10–8 m
C) 2.09 ´ 10–18 m
D) 9.12 ´ 10–8 m
E) none of these

 

 

ANS:   B                     PTS:    1                      DIF:    Moderate        REF:    7.4

KEY:   Chemistry | general chemistry | atomic theory | light | Bohr theory | atomic line spectra        MSC:            Quantitative

 

  1. Which of the following is a reasonable criticism of the Bohr model of the atom?
A) It makes no attempt to explain why the negative electron does not eventually fall into the positive nucleus.
B) It does not adequately predict the line spectrum of hydrogen.
C) It does not adequately predict the ionization energy of the valence electron(s) for elements other than hydrogen.
D) It does not adequately predict the ionization energy of the first energy level electrons for one-electron species for elements other than hydrogen.
E) It shows the electrons to exist outside of the nucleus.

 

 

ANS:   C                     PTS:    1                      DIF:    Moderate        REF:    7.4

KEY:   Chemistry | general chemistry | atomic theory | light | Bohr theory

MSC:   Conceptual

 

  1. When an electron in a 2p orbital of a particular atom makes a transition to the 2s orbital, a photon of approximate wavelength 629.1 nm is emitted. The energy difference between these 2p and 2s orbitals is
A) 3.16 ´ 10–28 J
B) 3.16 ´ 10–19 J
C) 3.16 ´ 10–17 J
D) 1.25 ´ 10–31 J
E) none of these

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.4

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Quantitative

 

  1. The energy of the light emitted when a hydrogen electron goes from n = 2 to n = 1 is what fraction of its ground-state ionization energy?
A) 3/4
B) 1/2
C) 1/4
D) 1/8
E) 1/9

 

 

ANS:   A                     PTS:    1                      DIF:    Moderate        REF:    7.4

KEY:   Chemistry | general chemistry | atomic theory | light | Bohr theory | atomic line spectra        MSC:   Conceptual

 

  1. In Bohr’s atomic theory, when an electron moves from one energy level to another energy level more distant from the nucleus:
A) Energy is emitted.
B) Energy is absorbed.
C) No change in energy occurs.
D) Light is emitted.
E) None of these.

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.4

KEY:   Chemistry | general chemistry | atomic theory | light | Bohr theory

MSC:   Conceptual

 

  1. Which of the following is incorrect?
A) The emission spectrum of hydrogen contains a continuum of colors.
B) Diffraction produces both constructive and destructive interference.
C) All matter displays both particle and wavelike characteristics.
D) Niels Bohr developed a quantum model for the hydrogen atom.
E) The lowest possible energy state of a molecule or atom is called its ground state.

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.4

KEY:   Chemistry | general chemistry | atomic theory                       MSC:   Conceptual

 

  1. Which of the following statements is (are) true?
 I. An excited atom can return to its ground state by absorbing electromagnetic

radiation.

 II. The energy of an atom is increased when electromagnetic radiation is emitted

from it.

III. The energy of electromagnetic radiation increases as its frequency increases.
IV. An electron in the n = 4 state in the hydrogen atom can go to the n = 2 state by

emitting electromagnetic radiation at the appropriate frequency.

V. The frequency and wavelength of electromagnetic radiation are inversely

proportional to each other.

 

A) II, III, IV
B) III, V
C) I, II, III
D) III, IV, V
E) I, II, IV

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    7.4

KEY:   Chemistry | general chemistry | atomic theory | light             MSC:   Conceptual

 

  1. Bohr’s model correctly describes the hydrogen atom and other small atoms.

 

ANS:   F                      PTS:    1                      DIF:    Easy                REF:    7.4

KEY:   Chemistry | general chemistry | atomic theory | light | Bohr theory

MSC:   Conceptual

 

  1. A gamma ray of wavelength 1.00 ´ 10–8 cm has enough energy to remove an electron from a hydrogen atom.

 

ANS:   T                      PTS:    1                      DIF:    Moderate        REF:    7.4

KEY:   Chemistry | general chemistry | atomic theory | light | Bohr theory

MSC:   Quantitative

 

  1. Which of the following statements best describes the Heisenberg uncertainty principle?
A) The exact position of an electron is always uncertain.
B) The velocity of a particle can only be estimated.
C) It is impossible to accurately know both the exact location and momentum of a particle.
D) The location and momentum of a macroscopic object are not known with certainty.
E) The location and momentum of a particle can be determined accurately, but not the identity of the particle.

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.5

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | wave functions | Heisenberg’s uncertainty principle   MSC:   Conceptual

 

  1. Which of the following best describes an orbital?
A) space where electrons are unlikely to be found in an atom
B) space which may contain electrons, protons, and/or neutrons
C) the space in an atom where an electron is most likely to be found
D) small, walled spheres that contain electrons
E) a single space within an atom that contains all electrons of that atom

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.5

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics

MSC:   Conceptual

 

  1. Which of the following is not determined by the principal quantum number, n, of the electron in a hydrogen atom?
A) The energy of the electron.
B) the minimum wavelength of the light needed to remove the electron from the atom.
C) The size of the corresponding atomic orbital(s).
D) The shape of the corresponding atomic orbital(s).
E) All of the above are determined by n.

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.6

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers | principal quantum number                        MSC:   Conceptual

 

  1. How many f orbitals have the value n = 3?
A) 0
B) 3
C) 5
D) 7
E) 1

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.6

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers       MSC:   Conceptual

 

  1. How many f orbitals have n = 6?
A) 2
B) 7
C) 10
D) 5
E) 18

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.6

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers       MSC:   Conceptual

 

  1. If n = 2, how many orbitals are possible?
A) 3
B) 4
C) 2
D) 8
E) 6

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.6

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers       MSC:   Conceptual

 

  1. A given set of p orbitals consists of ______ orbitals.
A) 1
B) 2
C) 3
D) 4
E) 5

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.6

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers       MSC:   Conceptual

 

  1. Which of the following is an incorrect designation for an atomic orbital?
A) 1s
B) 3d
C) 1p
D) 4f
E) 6s

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.6

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers       MSC:   Conceptual

 

  1. The number of orbitals having a given value of l is equal to
A) 2l + 1
B) 2n + 2
C) 3l
D) l + ml
E) the number of lobes in each orbital

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.6

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers | angular momentum quantum number                     MSC:              Conceptual

 

  1. The magnetic quantum number is related to the orientation of the orbital in space relative to the other orbitals in the atom.

 

ANS:   T                      PTS:    1                      DIF:    Easy                REF:    7.6

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers | magnetic quantum number                        MSC:   Conceptual

 

  1. Consider the following representation of a 2p-orbital:

Which of the following statements best describes the movement of electrons in a p-orbital?

A) The electrons move along the outer surface of the p-orbital, similar to a “figure 8” type of movement.
B) The electrons move within the two lobes of the p-orbital, but never beyond the outside surface of the orbital.
C) The electrons are concentrated at the center (node) of the two lobes.
D) The electrons are only moving in one lobe at any given time.
E) The electron movement cannot be exactly determined.

 

 

ANS:   E                     PTS:    1                      DIF:    Moderate        REF:    7.7

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | wave functions | Heisenberg’s uncertainty principle   MSC:   Conceptual

 

  1. A point in the wave function where the amplitude is zero defines
A) the node
B) the excited state
C) the amplitude of the wave function
D) the frequency of radiation
E) none of the above

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.7

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | wave functions

MSC:   Conceptual

 

  1. The size of an orbital is arbitrarily defined.

 

ANS:   T                      PTS:    1                      DIF:    Easy                REF:    7.7

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | atomic orbital shapes  MSC:   Conceptual

 

  1. How many electrons in an atom can have the quantum numbers n = 3, l = 2?
A) 2
B) 5
C) 10
D) 18
E) 6

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.8

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers       MSC:   Conceptual

 

  1. How many electrons can be described by the quantum numbers n = 3, = 3, ml = 1?
A) 0
B) 2
C) 6
D) 10
E) 14

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.8

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers       MSC:   Conceptual

 

  1. How many electrons can be contained in all of the orbitals with n = 4?
A) 2
B) 8
C) 10
D) 18
E) 32

 

 

ANS:   E                     PTS:    1                      DIF:    Moderate        REF:    7.8

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers       MSC:   Conceptual

 

  1. What is the l quantum number for a 4s orbital?
A) 1
B) 0
C) 3
D) 2
E) more than one of the above

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.8

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers       MSC:   Conceptual

 

  1. Which of the following could not be a valid ml quantum number for a 4d orbital?
A) 2
B) 0
C) –2
D) 1
E) 4

 

 

ANS:   E                     PTS:    1                      DIF:    Easy                REF:    7.8

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers       MSC:   Conceptual

 

  1. How many electrons in an atom can have the quantum numbers n = 4, l = 2?
A) 14
B) 12
C) 5
D) 10
E) 6

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    7.8

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers       MSC:   Conceptual

 

  1. Which of the following combinations of quantum numbers (n, l, ml, ms) do not represent permissible solutions of the Schrödinger equation for the electron in the hydrogen atom (i.e., which combination of quantum numbers is not allowed)?
A) 9, 8, -4, 1/2
B) 8, 2, 2, 1/2
C) 6, -5, -1, 1/2
D) 6, 5, -5, 1/2
E) All are allowed.

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.8

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers       MSC:   Conceptual

 

  1. If l = 3, how many electrons can be contained in all the possible orbitals?
A) 7
B) 6
C) 14
D) 10
E) 5

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.8

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers       MSC:   Conceptual

 

  1. Which of the following combinations of quantum numbers is not allowed?
A) n = 1, l = 1, ml = 0, ms =
B) n = 3, l = 0, ml = 0, ms = –
C) n = 2, l = 1, ml = -1, ms =
D) n = 4, l = 3, ml = -2, ms = –
E) n = 4, l = 2, ml = 0, ms =

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.8

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers       MSC:   Conceptual

 

  1. The small, but important, energy differences between 3s, 3p, and 3d orbitals are due mainly to
A) the number of electrons they can hold
B) their principal quantum number
C) the Heisenberg uncertainty principle
D) the penetration effect
E) Hund’s rule

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    7.9

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics

MSC:   Conceptual

 

  1. Who was the first chemist to recognize patterns in chemical properties of the elements?
A) Mendeleev
B) Newlands
C) Meyer
D) Dobereiner
E) Bohr

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    7.1

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements

MSC:   Conceptual

 

  1. Mendeleev is given the most credit for the concept of a periodic table of the elements because:
A) He had the longest history of research in elemental properties.
B) He emphasized its usefulness in predicting the existence and properties of unknown elements.
C) His representation of the table was the most understandable.
D) His periodic table was arranged in octaves.
E) He grouped elements into triads of similar properties.

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.1

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | Mendeleev’s predictions                     MSC:              Conceptual

 

  1. Which of the following was not an elemental property usually predicted by Mendeleev for as-yet-unknown elements?
A) electron configuration
B) atomic mass
C) density
D) boiling point
E) oxide formula

 

 

ANS:   A                     PTS:    1                      DIF:    Moderate        REF:    7.1

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | Mendeleev’s predictions                     MSC:              Conceptual

 

  1. Which of the following atoms or ions has three unpaired electrons?
A) N
B) O
C) Al
D) S2–
E) Ti2+

 

 

ANS:   A                     PTS:    1                      DIF:    Moderate        REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration | aufbau principle                      MSC:   Conceptual

 

  1. The electron configuration for the barium atom is:
A) 1s22s22p63s23p64s23d10
B) [Xe]6s2
C) 1s22s22p63s23p64s1
D) 1s22s22p63s23p64s2
E) none of these

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration | aufbau principle                      MSC:   Conceptual

 

  1. The electron configuration for the carbon atom is:
A) 1s22s22p2
B) [He]2s4
C) [Ne]2s22p2
D) 1s22p4
E) none of these

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration | aufbau principle                      MSC:   Conceptual

 

  1. The complete electron configuration of tin is
A) 1s22s22p63s23p64s23d104p65s24d105d105p2
B) 1s22s22p63s23p64s23d104d104p2
C) 1s22s22p63s23p64s24p65s24d105d105p2
D) 1s22s22p63s23p64s23d104p65s24d105p2
E) none of these

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration | aufbau principle                      MSC:   Conceptual

 

  1. Which of the following statements about quantum theory is incorrect?
A) The energy and position of an electron cannot be determined simultaneously.
B) Lower energy orbitals are filled with electrons before higher energy orbitals.
C) When filling orbitals of equal energy, two electrons will occupy the same orbital before filling a new orbital.
D) No two electrons can have the same four quantum numbers.
E) All of these are correct.

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory                       MSC:   Conceptual

 

  1. Which of the following statements is true?
A) The exact location of an electron can be determined if we know its energy.
B) An electron in a 2s orbital can have the same n, l, and ml quantum numbers as an electron in a 3s orbital.
C) Ni has two unpaired electrons in its 3d orbitals.
D) In the buildup of atoms, electrons occupy the 4f orbitals before the 6s orbitals.
E) Only three quantum numbers are needed to uniquely describe an electron.

 

 

ANS:   C                     PTS:    1                      DIF:    Moderate        REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory                       MSC:   Conceptual

 

  1. Which of the following statements is false?
A) An orbital can accommodate at most two electrons.
B) The electron density at a point is proportional to y2 at that point.
C) The spin quantum number of an electron must be either + or –.
D) A 2p orbital is more penetrating than a 2s; i.e., it has a higher electron density near the nucleus and inside the charge cloud of a 1s orbital.
E) In the usual order of filling, the 6s orbital is filled before the 4f orbital.

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory                       MSC:   Conceptual

 

  1. The statement that “the lowest energy configuration for an atom is the one having the maximum number of unpaired electrons allowed by the Pauli principle in a particular set of degenerate orbitals” is known as
A) the aufbau principle
B) Hund’s rule
C) Heisenberg uncertainty principle
D) the Pauli exclusion principle
E) the quantum model

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration | Hund’s rule                              MSC:   Conceptual

 

  1. An element has the electron configuration [Kr] 5s24d105p2. The element is a(n)
A) nonmetal
B) transition element
C) metal
D) lanthanide
E) actinide

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table              MSC:   Conceptual

 

  1. An element E has the electron configuration [Kr] 5s24d105p2. The formula for the fluoride of E is most likely
A) EF14
B) EF4
C) EF
D) EF6
E) EF8

 

 

ANS:   B                     PTS:    1                      DIF:    Moderate        REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table              MSC:   Conceptual

 

  1. An element with the electron configuration [Xe] 6s24f145d7 would belong to which class on the periodic table?
A) transition elements
B) alkaline earth elements
C) halogens
D) rare earth elements
E) none of the above

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table              MSC:   Conceptual

 

  1. All alkaline earths have the following number of valence electrons:
A) 1
B) 3
C) 6
D) 2
E) none of these

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table              MSC:   Conceptual

 

  1. Ti has __________ in its d orbitals.
A) one electron
B) two electrons
C) three electrons
D) four electrons
E) none of these

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration            MSC:              Conceptual

 

  1. Germanium has __________ in its 4p orbitals.
A) one electron
B) two electrons
C) three electrons
D) four electrons
E) none of these

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration            MSC:              Conceptual

 

  1. Fe has __________ that is (are) unpaired in its d orbitals.
A) one electron
B) two electrons
C) three electrons
D) four electrons
E) none of these

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration | magnetic properties of atoms                                     MSC:              Conceptual

 

Nitrogen has five valence electrons. Consider the following electron arrangements.

2s 2p
a) ­¯ ­ ­ ­
b) ­ ­¯ ­ ¯
c) ­ ­­ ­ ­
d) ­¯ ­ ­
e) ­¯ ­¯ ­ ­

 

 

  1. Which represents the ground state for N?
A) option a
B) option b
C) option c
D) option d
E) option e

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration | orbital diagram                       MSC:   Conceptual

 

  1. Which represents the ground state for the N ion?
A) option a
B) option b
C) option c
D) option d
E) option e

 

 

ANS:   E                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration | orbital diagram                       MSC:   Conceptual

 

  1. In which group do all the elements have the same number of valence electrons?
A) P, S, Cl
B) Ag, Cd, Ar
C) Na, Ca, Ba
D) P, As, Se
E) none of these

 

 

ANS:   E                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration            MSC:              Conceptual

 

  1. An atom of fluorine contains nine electrons. How many of these electrons are in s orbitals?
A) 2
B) 4
C) 6
D) 8
E) none

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration | aufbau principle                      MSC:   Conceptual

 

  1. How many unpaired electrons are there in an atom of sulfur in its ground state?
A) 0
B) 1
C) 2
D) 3
E) 4

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration | magnetic properties of atoms                                     MSC:              Conceptual

 

  1. Of the following elements, which has occupied d orbitals in its ground-state neutral atoms?
A) Ba
B) Ca
C) Si
D) P
E) Cl

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table              MSC:   Conceptual

 

  1. Of the following elements, which needs three electrons to complete its valence shell?
A) Ba
B) Ca
C) Si
D) P
E) Cl

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table              MSC:   Conceptual

 

  1. Which of the following electron configurations is correct?
A) Ga:    [Kr]4s23d104p1
B) Mo:    [Kr]5s24d5
C) Ca:    [Ar]4s13d10
D) Br:    [Kr]4s23d104p7
E) Bi:    [Xe]6s24f145d106p3

 

 

ANS:   E                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration            MSC:              Conceptual

 

  1. 1s22s22p63s23p64s23d2 is the correct electron configuration for which of the following atoms?
A) Ca
B) Ti
C) Ge
D) Zr
E) none of these

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration            MSC:              Conceptual

 

  1. Which of the following atoms has three electrons in p orbitals in its valence shell?
A) Ba
B) Ga
C) V
D) Bi
E) none of these

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table              MSC:   Conceptual

 

  1. How many of the following electron configurations for the species in their ground state are correct?
I. Ca: 1s22s22p63s23p64s2
II. Mg: 1s22s22p63s1
III. V: [Ar]3s23d3
IV. As: [Ar]4s23d104p3
V. P: 1s22s22p63p5

 

A) 1
B) 2
C) 3
D) 4
E) 5

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table              MSC:   Conceptual

 

  1. The number of unpaired electrons in the outer subshell of a Cl atom is
A) 0
B) 1
C) 2
D) 3
E) none of these

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration            MSC:              Conceptual

 

  1. For which of the following elements does the electron configuration for the lowest energy state show a partially filled d orbital?
A) Ti
B) Rb
C) Cu
D) Ga
E) Kr

 

 

ANS:   A                     PTS:    1                      DIF:    Moderate        REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration            MSC:              Conceptual

 

  1. Which of the following electron configurations is different from that expected?
A) Ca
B) Sc
C) Ti
D) V
E) Cr

 

 

ANS:   E                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table | exceptions to the aufbau principle

MSC:   Conceptual

 

  1. Which of the following have 10 electrons in the d orbitals?
A) Mn
B) Fe
C) Cu
D) Zn
E) two of the above

 

 

ANS:   E                     PTS:    1                      DIF:    Moderate        REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table              MSC:   Conceptual

 

  1. Which of the following is the highest energy orbital for a silicon atom?
A) 1s
B) 2s
C) 3s
D) 3p
E) 3d

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table              MSC:   Conceptual

 

  1. When electron configurations differ from expected, it is because orbitals want to be half-filled.

 

ANS:   T                      PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table | exceptions to the aufbau principle

MSC:   Conceptual

 

  1. Copper exhibits the expected electron configuration.

 

ANS:   F                      PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table | exceptions to the aufbau principle

MSC:   Conceptual

 

  1. Which of the following processes represents the ionization energy of bromine?
A) Br(s)  Br+(g) + e
B) Br(l)  Br+(g) + e
C) Br(g)  Br+(g) + e
D) Br(s)  Br+(s) + e
E) Br2(g)  Br2+(g) + e

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Order the elements S, Cl, and F in terms of increasing ionization energy.
A) S, Cl, F
B) Cl, F, S
C) F, S, Cl
D) F, Cl, S
E) S, F, Cl

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Order the elements S, Cl, and F in terms of increasing atomic radii.
A) S, Cl, F
B) Cl, F, S
C) F, S, Cl
D) F, Cl, S
E) S, F, Cl

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | atomic radius                                    MSC:   Conceptual

 

  1. Which of the following atoms would have the largest second ionization energy?
A) Mg
B) Cl
C) S
D) Ca
E) Na

 

 

ANS:   E                     PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. The first ionization energy of Mg is 735 kJ/mol. The second ionization energy is
A) 735 kJ/mol
B) less than 735 kJ/mol
C) greater than 735 kJ/mol
D) More information is needed to answer this question.
E) None of these.

 

 

ANS:   C                     PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Which of the following exhibits the correct orders for both atomic radius and ionization energy, respectively? (smallest to largest)
A) S, O, F, and F, O, S
B) F, S, O, and O, S, F
C) S, F, O, and S, F, O
D) F, O, S, and S, O, F
E) none of these

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties      MSC:            Conceptual

 

  1. Choose the element with the highest ionization energy.
A) Na
B) Mg
C) Al
D) P
E) S

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Which of the following concerning second ionization energies is true?
A) That of Al is higher than that of Mg because Mg wants to lose the second electron, so it is easier to take the second electron away.
B) That of Al is higher than that of Mg because the electrons are taken from the same energy level, but the Al atom has one more proton.
C) That of Al is lower than that of Mg because Mg wants to lose the second electron, thus the energy change is greater.
D) That of Al is lower than that of Mg because the second electron taken from Al is in a p orbital, thus it is easier to take.
E) The second ionization energies are equal for Al and Mg.

 

 

ANS:   B                     PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Consider a planet where the temperature is so high that the ground state of an electron in the hydrogen atom is n = 4. What is the ratio of ionization energy for hydrogen on this planet compared to that on Earth?
A) 1 : 4
B) 4 : 1
C) 1 : 16
D) 16 : 1
E) 1 : 1

 

 

ANS:   C                     PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Consider the following orderings.
I. Na+ < Mg2+ < Al3+ < Si4+
II. Be < Mg < Ca < Sr
III. I < Br < Cl < F
IV. Al < Si < P < Cl

Which of these give(s) a correct trend in ionization energy?

A) III
B) II, IV
C) I, IV
D) I, III, IV
E) none of them

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodic table | periodic properties | ionization energy            MSC:              Conceptual

 

  1. List the following atoms in order of increasing ionization energy: Li, Na, C, O, F.
A) Li < Na < C < O < F
B) Na < Li < C < O < F
C) F < O < C < Li < Na
D) Na < Li < F < O < C
E) Na < Li < C < F < O

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Consider the ionization energy (IE) of the magnesium atom. Which of the following is not true?
A) The IE of Mg is lower than that of sodium.
B) The IE of Mg is lower than that of neon.
C) The IE of Mg is lower than that of beryllium.
D) The IE of Mg is higher than that of calcium.
E) The IE of Mg is lower than that of Mg+.

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Of the following elements, which has the lowest first ionization energy?
A) Ba
B) Ca
C) Si
D) P
E) Cl

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Of the following elements, which is most likely to form a negative ion with charge 1–?
A) Ba
B) Ca
C) Si
D) P
E) Cl

 

 

ANS:   E                     PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | electron affinity                                    MSC:              Conceptual

 

  1. Which of the following atoms has the largest ionization energy?
A) O
B) Li
C) Ne
D) Be
E) K

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Which of the following statements is true?
A) The first ionization potential of H is greater than that of He.
B) The ionic radius of Fe+ is larger than that of Fe3+.
C) The ionization energy of S2– is greater than that of Cl.
D) The atomic radius of Li is larger than that of Cs.
E) All are false.

 

 

ANS:   B                     PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties      MSC:            Conceptual

 

  1. Which of the following statements is false?
A) A sodium atom has a smaller radius than a potassium atom.
B) A neon atom has a smaller radius than an oxygen atom.
C) A fluorine atom has a smaller first ionization energy than an oxygen atom.
D) A cesium atom has a smaller first ionization energy than a lithium atom.
E) All are true.

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | atomic radius                                    MSC:   Conceptual

 

  1. The statement that the first ionization energy for an oxygen atom is lower than the first ionization energy for a nitrogen atom is
A) consistent with the general trend relating changes in ionization energy across a period from left to right, because it is easier to take an electron from an oxygen atom than from a nitrogen atom
B) consistent with the general trend relating changes in ionization energy across a period from left to right, because it is harder to take an electron from an oxygen atom than from a nitrogen atom
C) inconsistent with the general trend relating changes in ionization energy across a period from left to right, due to the fact that the oxygen atom has two doubly-occupied 2p orbitals and nitrogen has only one
D) inconsistent with the general trend relating changes in ionization energy across a period from left to right, due to the fact that oxygen has one doubly-occupied 2p orbital and nitrogen does not
E) incorrect

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Sodium losing an electron is an ________ process and fluorine losing an electron is an _______ process.
A) endothermic, exothermic
B) exothermic, endothermic
C) endothermic, endothermic
D) exothermic, exothermic
E) more information needed

 

 

ANS:   C                     PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties      MSC:            Conceptual

 

  1. Which of the following statements is true about the ionization energy of Mg+?
A) It will be equal to the ionization energy of Li.
B) It will be equal to and opposite in sign to the electron affinity of Mg.
C) It will be equal to and opposite in sign to the electron affinity of Mg+.
D) It will be equal to and opposite in sign to the electron affinity of Mg2+.
E) None of the above.

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties      MSC:            Conceptual

 

  1. Which of the following statements is true?
A) The krypton 1s orbital is smaller than the helium 1s orbital because krypton’s nuclear charge draws the electrons closer.
B) The krypton 1s orbital is larger than the helium 1s orbital because krypton contains more electrons.
C) The krypton 1s orbital is smaller than the helium 1s orbital because krypton’s p and d orbitals crowd the s orbitals.
D) The krypton 1s orbital and helium 1s orbital are the same size because both s orbitals can only have two electrons.
E) The krypton 1s orbital is larger than the helium 1s orbital because krypton’s ionization energy is lower, so it’s easier to remove electrons.

 

 

ANS:   A                     PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | atomic radius                                    MSC:   Conceptual

 

  1. Which of the following statements are false?
 I. It takes less energy to add an electron to nitrogen than to carbon because nitrogen

will be closer to achieving a noble gas configuration.

 II. It takes more energy to add an electron to fluorine than to oxygen because the radius

of fluorine is smaller and more repulsion would occur in the p-orbitals.

III. It takes more energy to add an electron to nitrogen than to carbon because of the

extra repulsions that would occur in the 2p orbitals.

IV. Less energy is released in adding an electron to iodine than to chlorine because

the radius of iodine is larger and the electron is added at a distance further

from the nucleus.

 

A) II, III
B) I, II, IV
C) III only
D) I, II
E) All of the above are false statements.

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | electron affinity                                    MSC:              Conceptual

 

  1. The second ionization energy for calcium is smaller than the first ionization energy.

 

ANS:   F                      PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Ionization energy increases with an increasing number of electrons.

 

ANS:   F                      PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. When examining the electromagnetic spectrum, why is it more harmful to be exposed to x-rays than radio waves over a period of time? In your explanation, include the concepts of frequency, waves, and energy. Also, draw transverse waves to assist in your explanation.

 

ANS:

X-rays have a shorter wavelength (in the 10–10 m range) and therefore a higher frequency (since c = ln). This means that the number of waves that penetrate your body over a period of time will be greater than the number of radio waves that hit your body in that same period of time (since radio waves have a longer wavelength and lower frequency). Refer to the picture below:

 

X rays

shorter l, higher n

 

Radio Waves

longer l, lower n

Since more x-ray waves penetrate your body, you are being exposed to more energy in the form of radiation, which can be harmful.

See Sec 7.1 and 7.2 of Zumdahl Chemistry.

 

PTS:    1                      DIF:    Moderate        REF:    7.2

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Conceptual

 

  1. Photogray lenses incorporate small amounts of silver chloride in the glass of the lens. The following reaction occurs in the light, causing the lenses to darken:

AgCl ® Ag + Cl

The enthalpy change for this reaction is 3.10 ´ 102 kJ/mol. Assuming all this energy is supplied by light, what is the maximum wavelength of light that can cause this reaction?

 

ANS:

3.86 ´ 10–7 m

 

Enthalpy change per AgCl = (3.10 ´ 102 kJ/mol)(1 mol/6.022 ´ 1023 molecules)(1000 J/1kJ) = 5.15 ´ 10–19 J/molecule

E = hc/l, therefore l = hc/E

l = (6.626 ´ 10–34 J s)(2.998 ´ 108 m/s) / (5.15 ´ 10–19 J) = 3.86 ´ 10–7 m (or 386 nm)

 

PTS:    1                      DIF:    Easy                REF:    7.2

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Quantitative

 

  1. Electromagnetic radiation can be viewed as a stream of “particles” called __________.

 

ANS:

photons

 

PTS:    1                      DIF:    Easy                REF:    7.2

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Conceptual

 

  1. __________ results when light is scattered from a regular array of points or lines.

 

ANS:

Diffraction

 

PTS:    1                      DIF:    Easy                REF:    7.2

KEY:   Chemistry | general chemistry | atomic theory | light             MSC:   Conceptual

 

  1. How does the Bohr theory explain the emission and absorption spectra of hydrogen?

 

ANS:

The Bohr model assumes the electron can occupy circular orbits with specific energies at corresponding specific distances from the nucleus. The electron can move from one orbital (energy level) to another by releasing or absorbing the amount of energy corresponding to the difference in energy between the two orbitals. The observed emission and absorption spectra show only the discrete emissions or absorptions for these energy differences.

 

See Sec. 7.4 of Zumdahl, Chemistry.

 

PTS:    1                      DIF:    Moderate        REF:    7.4

KEY:   Chemistry | general chemistry | atomic theory | light | Bohr theory | atomic line spectra        MSC:   Conceptual

 

  1. A specific wave function is called a(n) __________.

 

ANS:

orbital

 

PTS:    1                      DIF:    Easy                REF:    7.5

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | wave functions

MSC:   Conceptual

 

  1. The __________ quantum number is related to the size and energy of the orbital.

 

ANS:

principal (or n)

 

PTS:    1                      DIF:    Easy                REF:    7.6

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers | principal quantum number                        MSC:   Conceptual

 

  1. Consider the following sets of quantum numbers. Which set(s) represent(s) impossible combinations?
n l ml
Set a 1 0 1
Set b 3 3 0
Set c 2 1 1
Set d 3 2 –2
Set e 3 1 –2
Set f 2 0 0

 

 

ANS:

Sets a, b, and e represent impossible combinations.

 

Set a is impossible because ml can only have values from –l to +l. If l is 0, ml can only be 0.

Set b is impossible because l can only have values from 0 to n-1. When n = 3, l may be only 0, 1, or 2.

Set e is impossible because ml can only have values from –l to +l. If l is 1, ml can only be -1, 0, or +1.

See Sec. 7.6 in Zumdahl Chemistry.

 

PTS:    1                      DIF:    Easy                REF:    7.6

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers       MSC:   Conceptual

 

  1. A hydrogen 3s wave function has __________ (how many?) nodal planes and __________ (how many?) radial nodes (not counting r = 0).

 

ANS:

0 nodal planes and 2 radial nodes

 

Since s orbitals are spherical, so the nodes are also spherical surfaces. For s orbitals, the number of nodes is given by n-1.

See Sec. 7.7 in Zumdahl Chemistry.

 

PTS:    1                      DIF:    Difficult          REF:    7.7

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | atomic orbital shapes  MSC:   Conceptual

 

  1. Areas of zero probability of finding an electron are called _________.

 

ANS:

nodes (or nodal surfaces)

 

PTS:    1                      DIF:    Easy                REF:    7.7

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | atomic orbital shapes  MSC:   Conceptual

 

  1. The ____________ states that in a given atom no two electrons can have the same set of four quantum numbers.

 

ANS:

Pauli exclusion principle

 

PTS:    1                      DIF:    Easy                REF:    7.8

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration | Pauli exclusion principle      MSC:   Conceptual

 

  1. How many electrons in an atom can have the following quantum numbers?
  2. a) n = 3
  3. b) n = 2, l = 0
  4. c) n = 2, l = 2, ml = 0
  5. d) n = 2, l = 0, ml = 0, ms = 1/2

 

ANS:

  1. a) 18; b) 2; c) 0; d) 1

 

  1. a) The n = 3 level consists of an s, three p, and five d orbitals, each of which may contain 2 electrons, for a total of 18 electrons.
  2. b) n = 2, l = 0 describes the 2s orbital, which may contain 2 electrons.
  3. c) This set of quantum numbers is impossible, since when n = 2, l can only be 0 or 1.
  4. d) This set of four quantum numbers describes one specific electron in the 2s

See Sec. 7.6 and 7.8 in Zumdahl Chemistry.

 

PTS:    1                      DIF:    Moderate        REF:    7.8

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers       MSC:   Conceptual

 

  1. Give the quantum numbers for the last electron in:
  2. a) gold
  3. b) magnesium
  4. c) iodine
  5. d) cadmium

 

ANS:

  1. a) gold: 5, 2, 2, (into a 5d-orbital)
  2. b) magnesium: 3, 0, 0, (into a 3s-orbital)
  3. c) iodine: 5, 1, 1, (into a 5p-orbital)
  4. d) cadmium: 4, 2, 2, (into a 4d-orbital)

 

PTS:    1                      DIF:    Moderate        REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers       MSC:   Conceptual

 

Given the following electronic configuration of neutral atoms, identify the element and state the number of unpaired electrons in its ground state:

 

  1. [Ar]4s13d5

 

ANS:

The element is Cr with six unpaired electrons in its ground state.

 

PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table | exceptions to the aufbau principle

MSC:   Conceptual

 

  1. [Ne]3s23p5

 

ANS:

The element is Cl with one unpaired electron in its ground state.

 

PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table              MSC:   Conceptual

 

  1. [Kr]5s24d105p4

 

ANS:

The element is Te with two unpaired electrons in its ground state.

 

PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table              MSC:   Conceptual

 

  1. [Ar]4s13d10

 

ANS:

The element is Cu with one unpaired electron in its ground state.

 

PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table | exceptions to the aufbau principle

MSC:   Conceptual

 

  1. [He]2s22p3

 

ANS:

The element is N with three unpaired electrons in its ground state.

 

PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table              MSC:   Conceptual

 

Write the electron configuration for the following:

 

  1. P

 

ANS:

1s22s22p63s23p3 or [Ne]3s23p3

 

PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration            MSC:              Conceptual

 

  1. Ag

 

ANS:

1s22s22p63s23p64s23d104p65s14d10 or [Kr]5s14d10

 

PTS:    1                      DIF:    Moderate        REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration            MSC:              Conceptual

 

  1. S2–

 

ANS:

1s22s22p63s23p6 or [Ne]3s23p6

 

PTS:    1                      DIF:    Moderate        REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration            MSC:              Conceptual

 

  1. I

 

ANS:

1s22s22p63s23p64s23d104p65s24d105p5 or [Kr]5s24d105p5

 

PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration            MSC:              Conceptual

 

  1. K+

 

ANS:

1s22s22p63s23p6 or [Ar]

 

PTS:    1                      DIF:    Moderate        REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration            MSC:              Conceptual

 

  1. The __________ electrons are in the outermost principal quantum level of an atom.

 

ANS:

valence

 

PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration            MSC:              Conceptual

 

  1. In general, the ionization energy and electron affinity involve more energy from __________ (left to right or right to left) in a period of the periodic table. Why?

 

ANS:

The increase is from left to right because of the increase in nuclear charge.

 

PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties      MSC:            Conceptual

 

  1. In general, the ionization energy and electron affinity involve more energy from _________ (top to bottom or bottom to top) in a family of the periodic table. Why?

 

ANS:

The increase is from bottom to top because the electrons being removed or added are closer to the nucleus.

 

PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties      MSC:            Conceptual

 

  1. For the set of elements Be, B, C, and N, which element has the smallest ionization energy? Explain any deviation from the expected pattern.

 

ANS:

B has the smallest ionization energy. This is a deviation from the expectation that ionization energy increases from left to right across a row on the periodic table. In boron, the outermost electron is in a higher p sublevel, and the filled 2s orbital just below it provides some shielding from the nuclear charge.

See Sec. 7.12 in Zumdahl Chemistry.

 

PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. For the set of elements Li, O, Ne, and Na, which element has the largest atomic radius? Explain any deviation from the expected pattern.

 

ANS:

Na has the largest atomic radius. There is no deviation from the expected pattern.

 

Atomic radius is larger toward the left-hand end of a row, and increases as you go down a column.

See Sec. 7.12, especially Fig. 7.35, in Zumdahl Chemistry.

 

PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | atomic radius                                    MSC:   Conceptual

 

Choose the atom or ion using a periodic table.

 

  1. Larger first ionization energy, Li or Be

 

ANS:

Be

 

PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Larger first ionization energy, Na or Rb

 

ANS:

Na

 

PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Larger first ionization energy, Be or B

 

ANS:

Be

 

PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Larger first ionization energy, C or N

 

ANS:

N

 

PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Larger second ionization energy, Na or Mg

 

ANS:

Na

 

PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Larger atomic radius, P or Sb

 

ANS:

Sb

 

PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | atomic radius                                    MSC:   Conceptual

 

  1. Larger atomic radius, N or O

 

ANS:

N

 

PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | atomic radius                                    MSC:   Conceptual

 

  1. Larger atomic or ionic radius, F or F

 

ANS:

F

 

PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | atomic radius                                    MSC:   Conceptual

 

  1. Larger atomic or ionic radius, Mg or Mg2+

 

ANS:

Mg

 

PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | atomic radius                                    MSC:   Conceptual

 

  1. Larger atomic radius, Fe2+ or Fe3+

 

ANS:

Fe2+

 

PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | atomic radius                                    MSC:   Conceptual

 

  1. The calcium atom is much larger than the calcium ion, while the fluorine atom is much smaller than the fluorine ion. Explain this natural occurrence.

 

ANS:

A cation has a larger proton to electron ratio than the corresponding neutral atom, so the remaining electrons are more closely held. An anion has a smaller proton to electron ratio than its corresponding neutral atom, so the electrons can not be held as closely.

See Sec. 7.12 of Zumdahl, Chemistry.

 

PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | atomic radius                                    MSC:   Conceptual

 

Consider the graph below to answer the next two questions:

 

  1. Explain why argon has the highest ionization energy.

 

ANS:

Argon has the highest ionization energy because the electrons in the valence shell are more tightly bound due to the higher nuclear charge. (NOTE: A common misconception among students is to say that argon has the highest ionization energy because it has a “filled outer valence shell.”)

See Sec. 7.12 in Zumdahl Chemistry.

 

PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Explain the ionization energy difference between sodium and potassium.

 

ANS:

Potassium has a slightly lower ionization energy than sodium because the electron being removed from potassium is farther from the nucleus (the electron is in a higher energy level) so it is not as tightly bound.

See Sec. 7.12 in Zumdahl Chemistry.

 

PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Which has these types of electromagnetic radiation arranged in order of decreasing frequency?
A) visible, ultraviolet, x-ray
B) radiowaves, visible, ultraviolet
C) ultraviolet, visible, infrared
D) x-ray, visible, ultraviolet
E) gamma, microwave, visible

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.1

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Conceptual

 

  1. Which has these types of electromagnetic radiation arranged in order of increasing wavelength?
A) visible, ultraviolet, x-ray
B) radiowaves, visible, ultraviolet
C) ultraviolet, visible, infrared
D) x-ray, visible, ultraviolet
E) none of these

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.1

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Conceptual

 

  1. Which has these types of electromagnetic radiation arranged in order of decreasing energy?
A) visible, ultraviolet, x-ray
B) radiowaves, visible, ultraviolet
C) ultraviolet, visible, infrared
D) x-ray, visible, ultraviolet
E) none of these

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.1

KEY:   Chemistry | general chemistry | atomic theory | light | electromagnetic radiation

MSC:   Conceptual

 

  1. The first three levels of the hydrogen atom are shown below with their energies in J.  Which answer contains all the possible photons that could be generated by transitions among the three levels and no others?

 

n                      E (J)

3 ________     -2.42 x 10-19

2 ________     -5.45 x 10-19

1 ________     -2.18 x 10-18

 

A) one photon, E = 1.94 x 10-18 J
B) two photons, E = 1.94 x 10-18 J and 1.64 x 10-18 J
C) two photons, E = 3.03 x 10-19 J and 1.64 x 10-18 J
D) photons, E = 3.03 x 10-19 J, 1.94 x 10-18 J and 1.64 x 10-18 J

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    7.4

KEY:   Chemistry | general chemistry | atomic theory | light | Bohr theory | atomic line spectra        MSC:            Quantitative

 

  1. The energy of the light emitted when a hydrogen electron goes from n = 3 to n = 1 is what fraction of its ground-state ionization energy?
A) 2/3
B) 1/3
C) 10/9
D) 8/9
E) 1/9

 

 

ANS:   D                     PTS:    1                      DIF:    Moderate        REF:    7.4

KEY:   Chemistry | general chemistry | atomic theory | light | Bohr theory | atomic line spectra        MSC:   Conceptual

 

  1. In the quantum theory, the magnetic orbital momentum quantum number is most directly associated with which property of orbitals?
A) energy C) orientation
B) size D) shape

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.6

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers | magnteic quantum number                        MSC:   Conceptual

 

  1. In the quantum theory, the angular orbital momentum quantum number is most directly associated with which property of orbitals?
A) energy C) orientation
B) size D) shape

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    7.6

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers | angular quantum number                        MSC:   Conceptual

 

  1. Select a correct set of quantum numbers (n, l, ml, ms) for the highest energy electron in the ground state of tin, Sn
A) 5, 1, 2, +1/2
B) 5, 2, -1, 1/2
C) 5, 1, 1, 1
D) 5, 1, 0, +1/2
E) 5, 2, 0, -1/2

 

 

ANS:   D                     PTS:    1                      DIF:    Easy                REF:    7.8

KEY:   Chemistry | general chemistry | atomic theory | quantum mechanics | quantum numbers       MSC:   Conceptual

 

  1. The ground state electron configuration for Te is:
A) [Kr]5s24d105p4
B) [Kr]5s25p64d8
C) [Kr]5s25d105p4
D) [Kr]5s24f14
E) Kr]5s25d105p6

 

 

ANS:   A                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration | aufbau principle                      MSC:   Conceptual

 

  1. Select the correct electron configuration for Cu.
A) [Ar]4s23d9
B) [Ar]4s13d10
C) [Ar]4s24p63d3
D) [Ar]4s24d9
E) [Ar]3d10

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.11

KEY:   Chemistry | general chemistry | atomic theory | electronic structure of atoms | electron configuration and the periodic table | exceptions to the aufbau principle

MSC:   Conceptual

 

  1. Which of the following equations correctly represents the process involved in the electron affinity of X?
A) X+(g) + e  =>  X(g)
B) X+(g) + Y(g)  =>  XY(g)
C) X(g) + e  =>  X(g)
D) X(g) => X+(g) + e
E) X+(g)  =>  X+(aq)

 

 

ANS:   C                     PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | electron affinity                                    MSC:              Conceptual

 

  1. Which of the following lists of atoms are arranged in order of INCREASING first ionization energy?

 

A) Li < O < N < F
B) Li < N < O < F
C) F < O < N < Li
D) Na < Sr < O < F
E) Ca > Cs > S > Se

 

 

ANS:   A                     PTS:    1                      DIF:    Moderate        REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual

 

  1. Which of the following lists of atoms are arranged in order of DECREASING atomic radius?

 

A) Li > O > N > F
B) Li > N > O > F
C) F > O > N > Li
D) Na > Sr > O > F
E) Ca < Cs < S < Se

 

 

ANS:   B                     PTS:    1                      DIF:    Easy                REF:    7.12

KEY:   Chemistry | general chemistry | atomic theory | periodicity of the elements | periodic properties | ionization energy                         MSC:   Conceptual