58) Which of the following is the major contributor to energy consumption?
A) residential
B) commercial
C) transportation
D) industrial
E) atmospheric
Algorithmic Questions
1) For a process at constant pressure, 49,600 calories of heat are released. This quantity of heat is
equivalent to
A) 4.82 × 10-6 J.
B) 1.19 × 104 J.
C) 1.24 × 104 J.
D) 2.08 × 105 J.
2) Which of the following is TRUE if ΔEsys = – 115 J?
A) The system is gaining 115 J, while the surroundings are losing 115 J.
B) The system is losing 115 J, while the surroundings are gaining 115 J.
C) Both the system and the surroundings are gaining 115 J.
D) Both the system and the surroundings are losing 115 J.
E) None of the above are true.
3) Calculate the change internal energy (ΔE) for a system that is giving off 65.0 kJ of heat and is
performing 855 J of work on the surroundings.
A) 64.1 kJ
B) -64.1 kJ
C) -65.9 kJ
D) 9.00 x 102 kJ
E) -9.00 x 102 kJ
4) Calculate the kinetic energy of a 150 g baseball moving at a speed of 39. m/s (87 mph).
A) 5.8 J
B) 1.1 × 102 J
C) 5.8 × 103 J
D) 1.1 × 105 J
5) Define heat capacity.
A) the quantity of heat required to lower the temperature of 1 mole of a substance by 1°C
B) the quantity of heat required to change a system’s temperature by 1°C
C) the quantity of heat required to lower the temperature of 1 gram of a substance by 1°C
D) the quantity of heat required to raise the temperature of 1 g of a substance by 1°F
E) the quantity of heat required to lower the temperature of 1 liter of a substance by 1°C
6) Define specific heat capacity.
A) the quantity of heat required to lower the temperature of 1 mole of a substance by 1°C
B) the quantity of heat required to change a system’s temperature by 1°C
C) the quantity of heat required to raise the temperature of 1 gram of a substance by 1°C
D) the quantity of heat required to lower the temperature of 1 gram of a substance by 1°F
E) the quantity of heat required to lower the temperature of 1 liter of a substance by 1°C
7) Define molar heat capacity.
A) the quantity of heat required to raise the temperature of 1 mole of a substance by 1°C
B) the quantity of heat required to change a system’s temperature by 1°C
C) the quantity of heat required to raise the temperature of 1 gram of a substance by 1°C
D) the quantity of heat required to lower the temperature of 1 g of a substance by 1°F
E) the quantity of heat required to lower the temperature of 1 liter of a substance by 1°C
8) Give the units of heat capacity.
A) J/°C
B) J/g °C
C) Jmole/°C
D) g/°C
E) mole/°C
9) Give the units of specific heat capacity.
A) J/°C
B) J/g °C
C) Jmole °C
D) g/°C
E) gmole °C
10) Which of the following substances (with specific heat capacity provided) would show the greatest
temperature change upon absorbing 100.0 J of heat?
A) 10.0 g Cu, CCu = 0.385 J/g°C
B) 10.0 g H2O, CH2O = 4.18 J/g°C
C) 10.0 g ethanol, Cethanol = 2.42 J/g°C
D) 10.0 g Al, CAl = 0.903 J/g°C
E) 10.0 g Pb, CPb= 0.128 J/g°C
11) A balloon is inflated from 0.0100 L to 0.400 L against an external pressure of 10.00 atm. How
much work is done in joules? 101.3 J = 1 L x atm
A) -39.5 J
B) 39.5 J
C) 0.395 J
D) -0.395 J
E) -395 J
12) A piece of iron (C=0.449 J/g°C) and a piece of gold (C=0.128 J/g°C) have identical masses. If the
iron has an initial temperature of 488 K and the gold has an initial temperature of 308 K, which of the
following statements is TRUE of the outcome when the two metals are placed in contact with one
another? Assume no heat is lost to the surroundings.
A) Since the two metals have the same mass, the final temperature of the two metals will be 398 K,
exactly halfway between the two initial temperatures.
B) Since the two metals have the same mass, but the specific heat capacity of gold is much smaller than
that of iron, the final temperature of the two metals will be closer to 308 K than to 488 K.
C) Since the two metals have the same mass, the thermal energy contained in the iron and gold after
reaching thermal equilibrium will be the same.
D) Since the two metals have the same mass, the thermal energy contained in each metal after
equilibrium will be the same.
E) None of the above are true.
13) Calculate the amount of heat (in kJ) required to raise the temperature of a 79.0 g sample of ethanol
from 298.0 K to 385.0 K. The specific heat capacity of ethanol is 2.42 J/g°C.
A) 57.0 kJ
B) 16.6 kJ
C) 73.6 kJ
D) 28.4 kJ
E) 12.9 kJ
20
14) Calculate the amount of heat (in kJ) necessary to raise the temperature of 53.8 g benzene by 50.6 K.
The specific heat capacity of benzene is 1.05 J/g°C
A) 1.61 kJ
B) 16.6 kJ
C) 2.59 kJ
D) 2.86 kJ
E) 3.85 kJ
15) Calculate the work, w, gained or lost by the system when a gas expands from 15 L to 40 L against a
constant external pressure of 1.5 atm. 101.3 L ∙ atm = 101 J
A) -6.1 kJ
B) -3.8 kJ
C) +3.8 kJ
D) +6.1 kJ
16) The specific heat capacity of liquid mercury is 0.14 J/gK. How many joules of heat are needed to
raise the temperature of 5.00 g of mercury from 15.0°C to 36.5°C?
A) 7.7 × 102 J
B) 15 J
C) 36 J
D) 0.0013 J
E) 1.7 J
17) The specific heat capacity of solid copper metal is 0.385 J/gK. How many joules of heat are needed
to raise the temperature of a 1.55-kg block of copper from 33.0°C to 77.5°C?
A) 1.79 × 105 J
B) 26.6 J
C) 2.66 × 104 J
D) 5.58 × 10-6 J
E) 0.00558 J
18) A 5.00-g sample of liquid water at 25.0 C is heated by the addition of 84.0 J of energy. The final
temperature of the water is ________°C. The specific heat capacity of liquid water is 4.18 J/gK.
A) 95.2
B) 25.2
C) -21.0
D) 29.0
E) 4.02
19) A 6.50-g sample of copper metal at 25.0°C is heated by the addition of 84.0 J of energy. The final
temperature of the copper is ________°C. The specific heat capacity of copper is 0.38 J/gK.
A) 29.9
B) 25.0
C) 9.0
D) 59.0
E) 34.0
20) The specific heat capacity of liquid water is 4.18 J/g-K. How many joules of heat are needed to raise
the temperature of 5.00 g of water from 25.1°C to 65.3°C?
A) 48.1 J
B) 840 J
C) 1.89 × 103 J
D) 2.08 × 10-2 J
E) 54.4 J
21) The specific heat capacity of methane gas is 2.20 J/g-K. How many joules of heat are needed to raise
the temperature of 5.00 g of methane from 36.0°C to 75.0°C?
A) 88.6 J
B) 429 J
C) 1221 J
D) 0.0113 J
E) 22.9 J
22) The specific heat of copper is 0.385 J/(g ∙ °C). If 34.2 g of copper, initially at 24.0°C, absorbs 4.689
kJ, what will be the final temperature of the copper?
A) 24.4°C
B) 26.8°C
C) 356°C
D) 380°C
23) A sample of copper absorbs 43.6 kJ of heat, resulting in a temperature rise of 30.0°C, determine the
mass (in kg) of the copper sample if the specific heat capacity of copper is 0.385 J/g°C.
A) 3.78 kg
B) 9.93 kg
C) 1.89 kg
D) 11.9 kg
E) 5.46 kg
24) It takes 11.2 kJ of energy to raise the temperature of 145 g of benzene from 23.0°C to 68.0°C. What
is the specific heat of benzene?
A) 1.14 J/(g ∙ °C)
B) 1.72 J/(g ∙ °C)
C) 3.48 J/(g ∙ °C)
D) 5.25 J/(g ∙ °C)
25) A 50.0-g sample of liquid water at 25.0°C is mixed with 29.0 g of water at 45.0°C. The final
temperature of the water is ________°C.
A) 102
B) 27.6
C) 35.0
D) 142
E) 32.3
26) What is the enthalpy change (in kJ) of a chemical reaction that raises the temperature of 250.0 mL of
solution having a density of 1.25 g/ml by 7.80°C? (The specific heat of the solution is 3.74 J/g∙K.)
A) -7.43 kJ
B) -12.51 kJ
C) 8.20 kJ
D) -9.12 kJ
E) 6.51 kJ
27) The combustion of titanium with oxygen produces titanium dioxide:
Ti(s) + O2(g) → TiO2(s)
When 2.060 g of titanium is combusted in a bomb calorimeter, the temperature of the calorimeter
increases from 25.00°C to 91.60°C. In a separate experiment, the heat capacity of the calorimeter is
measured to be 9.84 kJ/K. The heat of reaction for the combustion of a mole of Ti in this calorimeter is
________ kJ/mol.
A) 14.3
B) 19.6
C) -311
D) -0.154
E) -1.52 × 104
28) Identify what a bomb calorimeter measures.
A) measures ΔH for aqueous solutions
B) measures ΔE for combustion reactions
C) measures ΔH for reduction solutions
D) measures ΔT for aqueous solutions
E) measures ΔE for oxidation reactions
29) Calculate the change in internal energy (ΔE) for a system that is absorbing 35.8 kJ of heat and is
expanding from 8.00 to 24.0 L in volume at 1.00 atm. (Remember that 101.3 J = 1 L∙atm)
A) +51.8 kJ
B) -15.8 kJ
C) -16.6 kJ
D) -29.3 kJ
E) +34.2 kJ
30) When 0.455 g of anthracene, C14H10, is combusted in a bomb calorimeter that has a water jacket
containing 500.0 g of water, the temperature of the water increases by 8.63°C. Assuming that the
specific heat of water is 4.18 J/(g ∙ °C), and that the heat absorption by the calorimeter is negligible,
estimate the enthalpy of combustion per mole of anthracene.
A) +39.7 kJ/mol
B) -39.7 kJ/mol
C) -7060 kJ/mol
D) -8120 kJ/mol
31) Which of the following processes is endothermic?
A) the freezing of water
B) the combustion of butane
C) a hot cup of coffee (system) cools on a countertop
D) the chemical reaction in a “hot pack” often used to treat sore muscles
E) the vaporization of rubbing alcohol
32) Which of the following processes is exothermic?
A) a candle flame
B) baking bread
C) the chemical reaction in a “cold pack” often used to treat injuries
D) the vaporization of water
E) None of the above are exothermic.
33) Which of the following processes is endothermic?
A) mixing water and acid
B) rusting iron
C) photosynthesis
D) the electron affinity of a fluorine atom
E) None of the above processes are endothermic.
34) Using the following equation for the combustion of octane, calculate the heat of reaction for 400.0 g
of octane. The molar mass of octane is 114.33 g/mole.
2 C8H18 + 25 O2 → 16 CO2 + 18 H2O ΔH°rxn = -11018 kJ
A) 19280 kJ
B) 19.28 kJ
C) 38560 kJ
D) 50400 kJ
35) How much energy is evolved during the reaction of 51.2 g of Al, according to the reaction below?
Assume that there is excess Fe2O3.
Fe2O3(s) + 2 Al(s) → Al2O3(s) + 2 Fe(s) ΔH°rxn = -852 kJ
A) 51.2 kJ
B) 448 kJ
C) 224 kJ
D) 1617 kJ
E) 808 kJ
36) According to the following reaction, how much energy is required to decompose 59.0 kg of Fe3O4?
The molar mass of Fe3O4 is 231.55 g/mol.
Fe3O4(s) → 3 Fe(s) + 2 O2(g) ΔH°rxn = +1118 kJ
A) 1.42 × 105 kJ
B) 1.13 × 104 kJ
C) 2.85 × 105 kJ
D) 5.70 × 105 kJ
E) 8.55 × 105 kJ
37) Using the following thermochemical equation, determine the amount of heat produced from the
combustion of 24.3 g benzene (C6H6). The molar mass of benzene is 78.11 g/mole.
2 C6H6(l) + 15 O2(g) → 12 CO2(g) + 6 H2O(g) ΔH°rxn = -6278 kJ
A) 3910 kJ
B) 1950 kJ
C) 977 kJ
D) 40.1 kJ
E) 0.302 kJ
38) For a particular process that is carried out at constant pressure, q = 145 kJ and w = -35 kJ. Therefore,
A) ΔE = 110 kJ and ΔH = 145 kJ.
B) ΔE = 145 kJ and ΔH = 110 kJ.
C) ΔE = 145 kJ and ΔH = 180 kJ.
D) ΔE = 180 kJ and ΔH = 145 kJ.
39) When 5.00 mol of benzene is vaporized at a constant pressure of 1.00 atm and at its normal boiling
point of 80.1°C, 169.5 kJ are absorbed and PΔV for the vaporization process is equal to 14.5 kJ then
A) ΔE = 155.0 kJ and ΔH = 169.5 kJ.
B) ΔE = 184.0 kJ and ΔH = 169.5 kJ.
C) ΔE = 169.5 kJ and ΔH = 184.0 kJ.
D) ΔE = 169.5 kJ and ΔH = 155.0 kJ.
40) When 10.00 moles of H2(g) reacts with 5.000 mol of O2(g) to form 10.00 mol of H2O(l) at 25°C
and a constant pressure of 1.00 atm. If 683.0 kJ of heat are released during this reaction, and PΔV is
equal to -37.00 kJ, then
A) ΔH° = +683.0 kJ and ΔE° = +720.0 kJ.
B) ΔH° = +683.0 kJ and ΔE° = +646.0 kJ.
C) ΔH° = –683.0 kJ and ΔE° = -646.0 kJ.
D) ΔH° = –683.0 kJ and ΔE° = -720.0 kJ.
41) At 1 atm pressure, the heat of sublimation of gallium is 277 kJ/mol and the heat of vaporization is
271 kJ/mol. To the correct number of significant figures, how much heat is required to melt 4.50 mol of
gallium at 1 atm pressure?
A) 6 kJ
B) 27 kJ
C) 250 kJ
D) 274 kJ
42) According to the following thermochemical equation, what mass of H2O (in g) must form in order
to produce 488 kJ of energy?
SiO2(s) + 4 HF(g) → SiF4(g) + 2 H2O(l) ΔH°rxn = -184 kJ
A) 34.0 g
B) 51 g
C) 27.1 g
D) 95.4 g
E) 47.8 g
43) How much heat is absorbed/released when 25.00 g of NH3(g) reacts in the presence of excess
O2(g) to produce NO(g) and H2O(l) according to the following chemical equation?
4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(l) ΔH° = 1168 kJ
A) 428.6 kJ of heat are absorbed.
B) 428.6 kJ of heat are released.
C) 1715 kJ of heat are absorbed.
D) 1715 kJ of heat are released.
44) How much heat is absorbed when 45.00 g of C(s) reacts in the presence of excess SO2(g) to produce
CS2(l) and CO(g) according to the following chemical equation?
5 C(s) + 2 SO2(g) → CS2(l) + 4 CO(g) ΔH° = 239.9 kJ
A) 179.8 kJ
B) 239.9 kJ
C) 898.5 kJ
D) 2158 kJ
45) At constant pressure, the combustion of 15.0 g of C2H6(g) releases 777 kJ of heat. What is ΔH for
the reaction given below?
2 C2H6(g) + 7 O2(g) → 4 CO2(g) + 6 H2O(l)
A) -129 kJ
B) -779 kJ
C) -1560 kJ
D) -3120 kJ
46) When 1.50 mol of CH4(g) reacts with excess Cl2(g) at constant pressure according to the chemical
equation shown below, 1062 kJ of heat are released. Calculate the value of ΔH for this reaction, as
written.
2 CH4(g) + 3 Cl2(g) → 2 CHCl3(l) + 3 H2(g) ΔH = ?
A) -1420 kJ
B) -708 kJ
C) +708 kJ
D) +1420 kJ
47) Identify what a coffee cup calorimeter measures.
A) measures ΔH for aqueous solutions
B) measures ΔE for hydrolysis reactions
C) measures ΔH for reduction solutions
D) measures ΔT for combustion solutions
E) measures ΔE for oxidation reactions
48) In the presence of excess oxygen, methane gas burns in a constant-pressure system to yield carbon
dioxide and water:
CH4 (g) + 2O2 (g) → CO2 (g) + 2H2(l) ΔH = -890.0 kJ
Calculate the value of q (kJ) in this exothermic reaction when 1.70 g of methane is combusted at
constant pressure.
A) -94.6 kJ
B) 0.0306 kJ
C) -0.0106 kJ
D) 32.7 kJ
E) -9.46 × 104 kJ
49) Hydrogen peroxide decomposes to water and oxygen at constant pressure by the following reaction:
2H2O2 (l) → 2H2O(l) + O2 (g) ΔH = -196 kJ
Calculate the value of q (kJ) in this exothermic reaction when 4.00 g of hydrogen peroxide decomposes
at constant pressure?
A) -23.1 kJ
B) -11.5 kJ
C) -0.0217 kJ
D) 1.44 kJ
E) -2.31 × 104 kJ
50) When 1.50 g of Ba(s) is added to 100.00 g of water in a container open to the atmosphere, the
reaction shown below occurs and the temperature of the resulting solution rises from 22.00°C to
33.10°C. If the specific heat of the solution is 4.18 J/(g ∙ °C), calculate ΔH for the reaction, as written.
Ba(s) + 2 H2O(l) → Ba(OH)2(aq) + H2(g) ΔH= ?
A) -431 kJ
B) -3.14 kJ
C) +3.14 kJ
D) +431 kJ
51) Sodium metal reacts with water to produce hydrogen gas and sodium hydroxide according to the
chemical equation shown below. When 0.025 mol of Na is added to 100.00 g of water, the temperature
of the resulting solution rises from 25.00°C to 35.75°C. If the specific heat of the solution is 4.18 J/(g ∙
°C), calculate ΔH for the reaction, as written.
2 Na(s) + 2 H2O(l) → 2 NaOH(aq) + H2(g) ΔH = ?
A) -5.41 kJ
B) -90.0 kJ
C) -180 kJ
D) -360 kJ
52) When 50.0 mL of 0.400 M Ca(NO3)2 is added to 50.0 mL of 0.800 M NaF, CaF2 precipitates, as
shown in the net ionic equation below. The initial temperature of both solutions is 23.0°C. Assuming
that the reaction goes to completion, and that the resulting solution has a mass of 100.00 g and a specific
heat of 4.18 J/(g ∙ °C), calculate the final temperature of the solution.
Ca2+(aq) + 2 F–(aq) → CaF2(s) ΔH° = -11.5 kJ
A) 22.45°C
B) 23.55°C
C) 24.10°C
D) 24.65°C
53) Identify a substance that is not in its standard state.
A) CO
B) Ba
C) H2
D) O2
E) Ne
54) Identify a substance that is not in its standard state.
A) O2
B) Zn
C) H
D) O3
E) Xe
55) Which of the following processes is exothermic?
A) the ionization of a potassium atom
B) the breaking of a Br-Br bond
C) the sublimation of dry ice (CO2(s))
D) the reaction associated with DH°f for an ionic compound
E) All of the above processes are exothermic.
56) Choose the reaction that illustrates ΔH°f for Mg(NO3)2.
A) Mg(s) + N2(g) + 3O2(g) → Mg(NO3)2(s)
B) Mg2+(aq) + 2 NO3–(aq) → Mg(NO3)2(aq)
C) Mg(s) + 2 N(g) + 6 O(g) → Mg(NO3)2(s)
D) Mg(NO3)2(aq) → Mg2+(aq) + 2 NO3–(aq)
E) Mg(NO3)2(s) → Mg(s) + N2(g) + 3O2(g)
57) Choose the reaction that illustrates ΔH°f for CsHCO3.
A) Cs(s) + H2(g) + C(s) + O2(g) → CsHCO3(s)
B) Cs+(aq) + HCO3 -1(aq) → CsHCO3(s)
C) Cs+(aq) + H2O(l) + CO2(g) → CsHCO3(s)
D) Cs(s) + 1/2 H2(g) + C(s) + 3/2 O2(g) → CsHCO3(s)
E) Cs(s) + 2 H(g) + C(s) + 3 O(g) → CsHCO3(s)
58) Identify the greatest source of energy in the United States.
A) petroleum
B) natural gas
C) water
D) coal
E) nuclear power
59) Identify a greenhouse gas.
A) CO2
B) H2
C) CO
D) NO
E) NO2
60) Identify an energy source that is not renewable.
A) solar
B) hydroelectric
C) nuclear energy
D) wind
E) water
Matching Questions
Match the following.
A) potential energy
B) thermal energy
C) chemical energy
D) kinetic energy
1) energy associated with the motion of an object
Diff: 1 Page Ref: 6.2
2) energy associated with the temperature of an object
Diff: 1 Page Ref: 6.2
3) energy associated with the position of an object
Diff: 1 Page Ref: 6.2
4) energy associated with the relative positions of electrons and nuclei in atoms and molecules
Diff: 1 Page Ref: 6.2
Match the following.
A) work done by the system on the surroundings
B) work done on the system by the surroundings
C) energy flows out of system into the surroundings
D) system gains thermal energy from the surroundings
E) system loses thermal energy to the surroundings
F) energy flows into the system from the surroundings
5) –ΔE
Diff: 1 Page Ref: 6.3
6) +ΔE
Diff: 1 Page Ref: 6.3
7) -w
Diff: 1 Page Ref: 6.3
8) +w
Diff: 1 Page Ref: 6.3
9) -q
Diff: 1 Page Ref: 6.3
10) + q
Diff: 1 Page Ref: 6.3
Short Answer Questions
1) Describe the energy changes that occur when a book is held 6 ft off the floor and then dropped.
2) Define chemical energy.
3) Where does the energy absorbed during an endothermic reaction go?
4) Explain the difference between ΔH and DE.
5) Give the temperature and pressure for the standard state for a liquid.
6) Why are the standard heats of formation for elements in their most stable form assigned a value of
“0”?
7) Give the equation with the elements in MgSO4 in their standard state as the reactants and MgSO4 as
the product.
8) Write the reaction illustrating ΔH°f of CaCO3 and draw the enthalpy diagram showing the relative
positions of the reactants and products if it is an exothermic reaction.