58) Given the data in the table below, ΔH°rxn for the reaction
3 Cl2 (g) + PH3 (g) → PCl3 (g) + 3 HCl (g)
is __________ kJ.
A) -385.77
B) -570.37
C) 570.37
D) 385.77
E) The ΔH°f of Cl2 (g) is needed for the calculation.
59) Given the data in the table below, ΔH°rxn for the reaction
PCl3 (g) + 3 HCl (g) → 3 Cl2 (g) + PH3 (g)
is __________ kJ.
A) -570.37
B) -385.77
C) 570.37
D) 385.77
E) The ΔH°f of Cl2 (g) is needed for the calculation.
60) Given the data in the table below and ΔH°rxn for the reaction
SO2Cl2 (g) + 2 H2O (l) → H2SO4 (l) + 2HCl (g) ΔH° = -62 kJ
ΔH°f of HCl (g) is __________ kJ/mol.
A) -184
B) 60
C) -92
D) 30
E) Insufficient data are given.
61) A 25.5-g piece of cheddar cheese contains 37% fat, 28% protein, and 4% carbohydrate. The
respective fuel values for protein, fat, and carbohydrate are 17, 38, and 17 kJ/g, respectively. The fuel
value for this piece of cheese is __________ kJ.
A) 450
B) 330
C) 790
D) 99
E) 260
62) The average fuel value of sugars is 17 kJ/g. A 2.0 L pitcher of sweetened Kool-Aid contains 400 g
of sugar. What is the fuel value (in kJ) of a 500 mL serving of Kool-Aid? (Assume that the sugar is the
only fuel source.)
A) 4.2 × 104
B) 1.7 × 103
C) 1.7 × 106
D) 1.7 × 102
E) 17
63) A meal containing a burger, fries, and a milkshake contains 53.0 grams of fat, 38.0 grams of protein,
and 152 grams of carbohydrate. The respective fuel values for protein, fat, and carbohydrate are 17, 38,
and 17 kJ/g, respectively. If swimming typically burns 1100.0 kJ/hour, __________ minutes of
swimming are required to completely burn off the meal.
A) 4.78
B) 33.5
C) 62.5
D) 10.5
E) 286
64) A slice of apple pie contains 14.0 grams of fat, 2.00 grams of protein, and 52.0 grams of
carbohydrate. The respective fuel values for protein, fat, and carbohydrate are 17, 38, and 17 kJ/g,
respectively. If cycling typically burns 1000.0 kJ/hour, __________ minutes of cycling are required to
completely burn off the slice of pie.
A) 1.45
B) 4.66
C) 8.25
D) 87.0
E) less than one minute
5.3 Algorithmic Questions
1) The kinetic energy of a 12.5-g object moving at a speed of 81.9 m/s is __________ J.
A) 145
B) 0.950
C) 41.9
D) 41900
E) 1450
2) The kinetic energy of a 23.2-g object moving at a speed of 93.6 m/s is __________ J.
A) 145
B) 102
C) 1450
D) 0.950
E) 102000
3) The value of ΔE for a system that performs 168 kJ of work on its surroundings and loses 79 kJ of heat
is __________ kJ.
A) +247
B) -247
C) +55
D) -55
E) -168
4) Calculate the value of ΔE in joules for a system that loses 73 J of heat and has 150 J of work
performed on it by the surroundings.
A) -73
B) -77
C) +77
D) +223
E) -223
5) The value of ΔH° for the reaction below is -72 kJ. __________ kJ of heat are released when 4.0 mol
of HBr is formed in this reaction.
H2 (g) + Br2 (g) → 2HBr (g)
A) 126
B) 72
C) 0.44
D) 144
E) -72
6) The value of ΔH° for the reaction below is -126 kJ. The amount of heat that is released by the
reaction of 20.0 g of Na2O2 with water is __________ kJ.
2 Na2O2 (s) + 2 H2O (l) → 4NaOH (s) + O2 (g)
A) 16.2
B) 32.3
C) 67.5
D) 64.6
E) -126
7) The value of ΔH° for the reaction below is -482 kJ. Calculate the heat (kJ) released to the
surroundings when 6.00 g of CO (g) reacts completely.
2CO (g) + O2 (g) → 2CO2 (g)
A) 1450
B) 103
C) 51.6
D) 482
E) -482
8) 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) + 2H2O (l) △H = -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
B) 0.0306
C) -0.0106
D) 32.7
E) -9.46 × 104
9) Hydrogen peroxide decomposes to water and oxygen at constant pressure by the following reaction:
2H2O2 (l) → 2H2O (l) + O2 (g) △H = -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
B) -11.5
C) -0.0217
D) 1.44
E) -2.31 × 104
10) 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
11) A sample of aluminum metal absorbs 8.32 J of heat, upon which the temperature of the sample
increases from 23.2 °C to 30.5 °C. Since the specific heat capacity of aluminum is 0.90 J/g-K, the mass
of the sample is __________ g.
A) 72
B) 1.3
C) 7.5
D) 65
E) 7.3
12) 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
B) 840
C) 1.89 × 103
D) 2.08 × 10-2
E) 54.4
13) 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
B) 429
C) 1221
D) 0.0113
E) 22.9
14) The specific heat capacity of liquid mercury is 0.14 J/g-K. 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
B) 15
C) 36
D) 0.0013
E) 1.7
15) The specific heat capacity of solid copper metal is 0.385 J/g-K. 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
B) 26.6
C) 2.66 × 104
D) 5.58 × 10-6
E) 0.00558
16) 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/g-K.
A) 95.2
B) 25.2
C) -21.0
D) 29.0
E) 4.02
17) The ΔH for the solution process when solid sodium hydroxide dissolves in water is 44.4 kJ/mol.
When a 10.1-g sample of NaOH dissolves in 250.0 g of water in a coffee-cup calorimeter, the
temperature increases from 23.0 °C to __________°C. Assume that the solution has the same specific
heat as liquid water, i.e., 4.18 J/g-K.
A) 35.2
B) 24.0
C) 33.7
D) 33.3
E) 40.2
18) 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
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/g-K.
A) 29.9
B) 25.0
C) 9.0
D) 59.0
E) 34.0
20) 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
joules/gram-K.)
A) -7.43
B) -12.51
C) 8.20
D) -9.12
E) 6.51
21) A 5-ounce cup of raspberry yogurt contains 6.0 g of protein, 2.0 g of fat, and 20.2 g of carbohydrate.
The fuel values for protein, fat, and carbohydrate are 17, 38, and 17 kJ/g, respectively. The fuel value of
this cup of yogurt is __________ kJ.
A) 520
B) 630
C) 340
D) 720
E) 72
5.4 Short Answer Questions
1) __________ is defined as the energy used to move an object against a force.
2) Given the equation
H2O (l) → H2O (g) ΔHrxn = 40.7 kJ at 100 °C
Calculate the mass of liquid water (in grams) at 100 °C that can converted to vapor by absorbing 2400 J
of heat.
3) Given the equation
H2O (l) → H2O (g) ΔHrxn = 40.7 kJ at 100°C
Calculate the heat required to convert 3.00 grams of liquid water at 100 °C to vapor.
4) When 0.800 grams of NaOH is dissolved in 100.0 grams of water, the temperature of the solution
increases from 25.00 °C to 27.06 °C. The amount of heat absorbed by the water is __________ J. (The
specific heat of water is 4.18 J/g- °C.)
5) Given the equation:
CH4 (g) + 2 O2 (g) → CO2 (g) + H2O (l) ΔH = -890 kJ
The heat liberated when 34.78 grams of methane (CH4) are burned in an excess amount of oxygen is
__________ kJ.
6) The standard enthalpy change of a reaction is the enthalpy change when all reactants and products are
at ________ pressure and a specific temperature.
7) Coal contains hydrocarbons of high molecular weight as well as compounds containing ________,
oxygen, or nitrogen.
5.5 True/False Questions
1) Work equals force times distance.
2) One joule equals 1 kg ∙ m2/s2.
3) Units of energy include newtons, joules, and calories.
4) The primary component of natural gas is propane.
5) Renewable energy sources are essentially inexhaustible.
6) Petroleum is a liquid composed of hundreds of compounds.