Multiple-Choice Questions
1. Which of the following equations represents cellular respiration?
a. C6H12O6(s) + 6O2(g)  6CO2(g) + 6H2O(g)
b. C6H12O6(s) + 6O2(g)  6CO2(g) + 6H2O(l)
c. 6CO2(g) + 6H2O(l)  C6H12O6(s) + 6O2(g)
d. 6CO2(g) + 6H2O(g)  C6H12O6(s) + 6O2(g)
2. The heat capacity of a calorimeter is 14.26 kJ/oC. By how much will its temperature change if it gains
526.8 kJ of thermal energy?
a. 36.9 oC
b. 54.1 oC
c. 0.27 oC
d. 14.3 oC
3. Which of the following reactions corresponds to the equation for the standard molar enthalpy of
formation for solid sodium chlorate, NaClO3?
3
a. NaCl(s) + O2(g)  NaClO2(s)
2
1
3
b. Na(s) + Cl2(g) + O2(g)  NaClO3(s)
2
2
c. Na(s) + Cl(g) + 3O(g)  NaClO3(s)
d.
2Na(s) + Cl2(g) + 3O2(g)  2NaClO3(s)
4. Given the reaction, 2NO(g) + O2(g) + 68 kJ  2NO2(g), what is the change in enthalpy, rH, for the
reaction NO(g) +
a.
b.
c.
d.
1
2
O2(g)  NO2(g)?
68 kJ
–68 kJ
34 kJ
–34 kJ
5. Given the reaction, Ca(s) + C(s) +
3
2
O2(g)  CaCO3(s) ΔrH = –1205.8 kJ, how much heat is
released when 3.75 g of calcium is allowed to react with excess oxygen and carbon?
a.
b.
c.
d.
1.29  104 kJ
4.22  103 kJ
1.21  103 kJ
1.13  102 kJ
6. The enthalpy of combustion for octane is 5470.1 kJ/mol. How much octane, C8H18(l), would have to
be burned to produce 397 kJ of energy?
a. 0.0726 g C8H18(l)
b. 8.29 g C8H18(l)
c. 13.8 g C8H18(l)
d. 1.57  103 g C8H18(l)
7. According to Hess’s law of heat summation, which of the following statements is true?
a. The enthalpy change is independent of the number of intermediate steps.
b. The enthalpy change depends on the pathway of the process.
c. The enthalpy change is independent of the pathway of the process.
d. Both A and C.
8. The enthalpy of reaction for the following equation, FeO(s) + CO(g) →Fe(s) + CO2(g), is:
a. 776 kJ
b. –776 kJ
c. 11.0 kJ
d. –11.0 kJ
Use the following information to answer the next question.
9. The amount of methanol that must be burned to raise the temperature of 250.0 g of water from 20.0oC
to 35.0oC is
a. 6.16 X 10-3 mol
b. 1.23 X 10-3 mol
c. 2.46 X 10-2 mol
d. 2.46 X 101 mol
10. An interpretation that applies to the data in the table above is that the greater the number of carbon
atoms in a fossil fuel molecule, the
a. Lower the energy stored in the molecule
b. Greater the strength of each covalent bond
c. Greater the energy released during combustion
d. Lower the moles of oxygen required for complete combustion
11. If 44.7 kJ of energy is transferred when 1.65 g of ethanol, CH3CHO(l), is burned in a calorimeter, then
the molar enthalpy of combustion of ethanol is
a. -1.67 kJ/mol
b. -2.71 X 101 kJ/mol
c. -7.38 X 101 kJ/mol
d. -1.19 X 103 kJ/mol
12. During photosynthesis, energy that originated from the
chemical bonds.
Row
i
A
sun
B
sun
C
plant
D
plant
i is converted to ii
energy and stored in
ii
light
chemical
light
chemical
13. If 1.00 g of sucrose reacts as represented by the equation above, then i
surroundings.
Row
i
ii
A
15.1 kJ
absorbed from
B
15.1 kJ
released to
C
0.0664 kJ
absorbed from
D
0.0664 kJ
released to
of energy is ii the
Use the following information to answer the next question
14. The molar enthalpy change for the combustion of butane gas, as represented by the equation above is
a. -2657.3 kJ/mol
b. -2877.3 kJ/mol
c. -5314.6 kJ/mol
d. -5754.6 kJ/mol
15. One reason that could explain why dynamite releases a large quantity of energy when it explodes is
that the reaction is
a. Endothermic, and the products have more potential energy than the reactants
b. Endothermic, and the reactants have more potential energy than the products
c. Exothermic, and the products have more potential energy than the reactants
d. Exothermic, and the reactants have more potential energy than the products
Use the following information to answer the next question
16. The energy barrier that must be overcome for the forward reaction to
occur is called the i , and in the diagram above, it is the difference
between ii
Row
A
B
C
D
i
enthalpy change
enthalpy change
activation energy
activation energy
ii
I and II
I and III
I and II
I and III
17. In the reaction represented by the equation above, energy is i
the products contain ii energy than the reactants.
Row
A
B
C
D
i
absorbed from
absorbed from
released to
released to
the surroundings because the bonds in
ii
more potential
more kinetic
less potential
less kinetic
Use the following information to answer the next question.
The decomposition of hot potassium chlorate to solid potassium chloride and oxygen gas occurs at a
faster rate in the presence of solid manganese(IV) oxide, as represented by the following equation:
2 KClO3(s) MnO2 (s) 2 KCl(s) + 3 O2(g)
18. When manganese(IV) oxide is used as a catalyst, the enthalpy change for the decomposition of
potassium chlorate
a. Stays the same
b. Becomes more exothermic
c. Becomes more endothermic
d. Changes from exothermic to endothermic
Numerical Response Questions
1. A piece of stainless steel with a mass of 1.60 g absorbs 141 J of energy when its temperature increases
by 178 °C. What is its specific heat capacity?
3. Liquid hydrogen peroxide is an oxidizing agent in many rocket fuel mixtures because it releases
oxygen gas on decomposition: 2H2O2(l)  2H2O(l) + O2(g) + 196.1 kJ. How much heat is released
when 6.50 g H2O2(l) decomposes?
4. The molar enthalpy of combustion of ethanol is –1234.8 kJ/mol. How much water can be heated from
13.5 °C to 24.7 °C by the combustion of 22.0 g of ethanol?
5. The enthalpy of combustion, cH, for heptane, C7H16(l), is 4464.7 kJ/mol. How much heat is
released by the burning of 10.0 g of heptane?
6. Rank the following compounds from most to least thermochemically stable.
a) CO2(g)
b) NaCl(s)
c) C2H2(g)
d) O2(g)
7. Given that the molar enthalpy of combustion for propan-1-ol, C3H7OH(l), is –2021 kJ/mol, what is the
molar enthalpy of formation for propan-1-ol? (Assume that the water in the products condenses into
its liquid state.)
8. How much energy is released in the production of 2.37 g of nitrogen dioxide according to the
following equation?
9.
NO(g) +
1
2
O2(g)  NO2(g)
10. The molar enthalpy of formation for cyclopropane, C3H6(g) is ______ kJ/mol.
11. The molar enthalpy of solution for ammonium nitrate in the calorimetry experiment
is _________ kJ/mol