Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
|
|
| 1. | Which
one of the following statements is INCORRECT? a. | The heat required to raise the temperature of 1.00 g
H2O(l) by 1.00
°C is 1.00
J. | b. | 1.000 calories
is equal to 4.184 J. | c. | 1.00 J is equal to 1.00
kg·m2·s-2. | d. | A dietary Calorie is equal to 1000
calories. | e. | 1000 calories is equal to 1 kcal. | | |
|
|
| 2. | How
many joules are equivalent to 235 calories? a. | 0.0178 J | b. | 56.2
J | c. | 983
J | d. | 5.62
´ 103
J | e. | 1.67
´ 104
J | | |
|
|
| 3. | Specific heat capacity is a. | the quantity of heat needed to change 1.00 g of a substance by
1.00 K. | b. | the mass of a substance that 1.00 J of energy will heat by 1.00
K. | c. | the mass of a
substance that 1.00 cal of energy will heat by 1.00 K. | d. | the temperature
change undergone when 1.00 g of a substance absorbs 4.184 J. | e. | the quantity of
heat required to melt 4.184 g of a substance. | | |
|
|
| 4. | If
136 J is required to change the temperature of 8.75 g of nickel by 35.0 K, what is the specific heat
capacity of mercury? a. | 0.0294 J/g·K | b. | 0.311
J/g·K | c. | 0.417 J/g·K | d. | 0.444
J/g·K | e. | 2.25 J/g·K | | |
|
|
| 5. | If
the same amount of heat is added to 5.00 g samples of each of the metals below, which metal will
experience the smallest temperature change?
Metal | Specific Heat
Capacity (J/g·K) | Al | 0.897 | Au | 0.129 | Cu | 0.385 | Fe | 0.449 | K | 0.753 | | |
|
|
| 6. | If
1.00 mole of ethanol, CH3CH2OH, at 22.0 °C absorbs 1.45
kJ of heat, what is the final temperature of the ethanol? The specific heat capacity of ethanol is
2.44 J/g·K. a. | 9.1 °C | b. | 22.0 °C | c. | 34.9 °C | d. | 47.0 °C | e. | 616 °C | | |
|
|
| 7. | Which
of the following statements is CORRECT? a. | If a reaction occurs at constant pressure, w =
DE. | b. | If a reaction occurs at constant pressure, q =
DH. | c. | If a reaction occurs at constant pressure, q =
DE. | d. | If a reaction occurs at constant volume, DE >
DH. | e. | If a reaction occurs at constant volume, w =
DE. | | |
|
|
| 8. | One
statement of the first law of thermodynamics is that a. | the amount of
work done on a system is dependent of pathway. | b. | the total work
done on a system must equal the heat absorbed by the system. | c. | the heat flow in
or out of a system is independent of pathway. | d. | the total energy
flow in or out of a system is equal to the sum of the heat transferred to or from the system and the
work done by or on the system. | e. | in any chemical process the heat flow must equal the change in
enthalpy. | | |
|
|
| 9. | The
thermochemical equation for the combustion of hexane is shown below.
C6H14(g) + 19/2 O2(g) ® 6
CO2(g) + 7 H2O(g) DH° = -4163 kJ
What is the enthalpy change for the combustion of 2.50 g
C6H14? a. | -121 kJ | b. | -1.66
´ 103
kJ | c. | -1.04
´ 104
kJ | d. | -1.43
´ 105
kJ | e. | -3.59
´ 105
kJ | | |
|
|
| 10. | Hydrazine, N2H4, is a liquid used as a rocket fuel. It reacts
with oxygen to yield nitrogen gas and water.
N2H4(l) + O2(g) ® N2(g) + 2 H2O(l)
The reaction of 3.80 g N2H4
evolves 73.7 kJ of heat. Calculate the enthalpy change per mole of hydrazine
combusted. a. | -8.74
kJ/mol | b. | -19.4 kJ/mol | c. | -2.80
´ 102
kJ/mol | d. | -622 kJ/mol | e. | -8.98
´ 103
kJ/mol | | |
|
|
| 11. | If
1.86 g MgO is combined with 100.0 mL of 1.00 M HCl (density 100.0 g/mL) in a coffee cup calorimeter,
the temperature of the resulting solution increases from 21.3 °C to 35.7
°C. Calculate the
enthalpy change for the reaction per mole of MgO. Assume that the specific heat capacity of the
solution is 4.18 J/g·K. a. | -6.13 kJ | b. | -28.3
kJ | c. | -133
kJ | d. | -329
kJ | e. | -613
kJ | | |
|
|
| 12. | A
2.885 g sample of methanol, CH3OH, is combusted in a bomb calorimeter. The temperature of
the calorimeter increases by 11.38 K. If the heat capacity of the bomb is 727.1 J/K and it contains
1.200 kg of water, what is the heat evolved per mole of methanol combusted? The specific heat
capacity of water is 4.184 J/g·K and the molar mass of methanol is 32.04 g/mol. a. | -65.41
kJ/mol | b. | -91.89 kJ/mol | c. | -634.5
kJ/mol | d. | -726.5 kJ/mol | e. | -1.019
´ 106
kJ/mol | | |
|
|
| 13. | Determine the heat of vaporization of titanium(IV) chloride given the enthalpies of
reaction below.
Ti(s) + 2 Cl2(g) ®
TiCl4(l) DH = -804.2 kJ
Ti(s) + 2 Cl2(g) ®
TiCl4(g) DH = -763.2 kJ
a. | -1567.4 kJ | b. | -41.0
kJ | c. | +1.054
kJ | d. | +41.0
kJ | e. | +1567.4
kJ | | |
|
|
| 14. | Determine the heat of reaction for the oxidation of iron,
4 Fe(s) + 3 O2(g) ® 2 Fe2O3(s)
given the thermochemical equations below.
2 Fe(s) + 6 H2O(l) ® 2 Fe(OH)3(s) + 3 H2(g) DH =
+321.8 kJ
2 H2O(l) ® 2 H2(g) + O2(g) DH =
+571.7 kJ
Fe2O3(s) + 3 H2O(l) ® 2
Fe(OH)3(s) DH = +288.6 kJ
a. | -1648.7 kJ | b. | -1182.1
kJ | c. | -505.3
kJ | d. | +360.5
kJ | e. | +1447.1
kJ | | |
|
|
| 15. | Calculate DH for the following reaction,
CaO(s) + CO2(g) ® CaCO3(s)
given the thermochemical equations below.
2 Ca(s) + O2(g) ® 2 CaO(s) DH = -1270.2 kJ
C(s) +
O2(g) ® CO2(g) DH = -393.5 kJ
2 Ca(s) + 2 C(s)
+ 3 O2(g) ® 2 CaCO3(s) DH = -2413.8 kJ
a. | -4077.3
kJ | b. | -750.1
kJ | c. | -178.3
kJ | d. | +350.2
kJ | e. | +2870.6
kJ | | |
|
|
| 16. | Calculate 
for the combustion of gaseous ethanol,
C2H5OH(g) + 3 O2(g) ® 2
CO2(g) + 3 H2O(g)
using standard molar enthalpies of
formation.
molecule |  (kJ/mol) | C2H5OH(g) | -235.3 | CO2(g) | -393.5 | H2O(g) | -241.8 | | |
a. | -1747.7
kJ | b. | -1277.1
kJ | c. | -793.5
kJ | d. | -400.0
kJ | e. | -83.6
kJ | | |
|
|
| 17. | The
standard molar enthalpy of formation of NH3(g) is -45.9 kJ/mol. What is the enthalpy
change if 5.38 g N2(s) and 3.32 g H2(g) react to produce
NH3(g)? a. | -75.6 kJ | b. | -50.4
kJ | c. | -17.6
kJ | d. | -8.81
kJ | e. | -1.20
kJ | | |
|
|
| 18. | Which
one of the following statements is INCORRECT? a. | Energy is neither created nor destroyed in chemical
reactions. | b. | Kinetic energy is the energy associated with
motion. | c. | Exothermic processes transfer heat from the surrounding into
the system. | d. | Increasing the thermal energy of a gas increases the motion of
its atoms. | e. | Energy is the capacity to do work. | | |
|
|
| 19. | Which
one of the following statements is INCORRECT? a. | In an exothermic process heat is transferred from the system to
the surroundings. | b. | The greater the heat capacity of an object, the more thermal
energy it can store. | c. | The SI unit of specific heat capacity is joules per gram per
Kelvin. | d. | The specific heat capacity has a positive value for liquids and
a negative value for gases. | e. | When heat is transferred from the system to the surroundings, q
is negative. | | |
|
|
| 20. | The
thermochemical equation for the combustion of butane is shown below.
C4H10(g) + 13/2 O2(g) ® 4
CO2(g) + 5 H2O(l) DH° = -2877 kJ
What is the enthalpy change for the following
reaction?
16 CO2(g) + 20 H2O(l) ® 4
C4H10(g) + 26 O2(g) a. | -5754
kJ | b. | -719.2
kJ | c. | +719.2
kJ | d. | +5754
kJ | e. | +1.151
´ 104
kJ | | |
|
|
| 21. | A
chemical reaction in a bomb calorimeter evolves 5.17 kJ of heat. If the heat capacity of the
calorimeter is 1.08 kJ/°C, what is the temperature change of the calorimeter? a. | 0.209
°C | b. | 4.09 °C | c. | 4.79 °C | d. | 5.58 °C | e. | 6.25 °C | | |
|
|
| 22. | The
molar enthalpy of combustion for glucose, C6H12O6, is -2803 kJ. A
mass of 1.150 g glucose is combusted in a bomb calorimeter. If the calorimeter contains 925 g
H2O and the bomb has a heat capacity of 622 J/K, what is the temperature increase of the
bomb calorimeter? The specific heat capacity of water is 4.184 J/g·K and the molar mass of
glucose is 180.2 g/mol. a. | 0.72 K | b. | 2.76
K | c. | 3.98
K | d. | 5.12
K | e. | 7.20
K | | |
|
|
| 23. | Which
of the following chemical equations corresponds to the standard molar enthalpy of formation of
N2O? a. | NO(g) + 1/2
N2(g) ® N2O(g) | b. | N2(g)
+ 1/2 O2(g) ® N2O(g) | c. | 2N(g) + O(g)
®
N2O(g) | d. | N2(g) + O(g) ®
N2O(g) | e. | 2 N2(g) + O2(g) ® 2
N2O(g) | | |
|