Question 1

Define heat capacity.

Accepted Answer

A)  the quantity of heat required to raise the temperature of 1 mol 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 g 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 raise the temperature of 1 L of a substance by 1 °C

Question 2

Match the following.

-energy associated with the position of an object

Accepted Answer

A)  kinetic energy
B)  potential energy
C)  chemical energy
D)  thermal energy

Question 3

According to the following thermochemical equation, what mass of H2O (in g) must form to produce 975 kJ of energy? SiO2(s) + 4HF(g) → SiF4(g) + 2H2O(l) ΔrH° = -184 kJ

Accepted Answer

A)  68.0 g
B)  102 g
C)  54.1 g
D)  191 g
E)  95.5 g

Question 4

10.618 g of an unknown salt is dissolved in a coffee cup calorimeter that contains 50.0 mL of water. The measured temperature decreased from 23.8 °C to 22.7 °C. Identify the unknown salt. The specific heat of water is 4.184 J g-1 °C-1, and assume the density of the solution is 1.00 g mL-1.

Accepted Answer

A)  NaF, ΔrH = 0.91 kJ mol-1
B)  NaBr, ΔrH = -0.60 kJ mol-1
C)  NaNO3, ΔrH = 20.50 kJ mol-1
D)  LiNO3, ΔrH = -2.51 kJ mol-1
E)  LiBr∙2H2O, ΔrH = -23.26 kJ mol-1

Question 5

Write the reaction illustrating ΔfH° of CaCO3 and draw the enthalpy diagram showing the relative positions of the reactants and products if it is an exothermic reaction.

Accepted Answer

Ca(s)+ C(s, graphite)+ 3/2 O₂(g...

Question 6

Calculate the final temperature of 82.1 g of molecular hydrogen (specific heat capacity = 14.304 J g-1 °C-1) initially at 5.48 °C that absorbs 57 kJ of energy from the surroundings.

Accepted Answer

A)  14 °C
B)  24 °C
C)  34 °C
D)  44 °C
E)  54 °C

Question 7

Identify a substance that is NOT in its standard state.

Accepted Answer

A)  CO
B)  Ca
C)  H2
D)  O2
E)  Ne

Question 8

Two aqueous solutions are both at room temperature and are then mixed in a coffee cup calorimeter. The reaction causes the temperature of the resulting solution to fall below room temperature. Which of the following statements is TRUE?

Accepted Answer

A)  The products have a lower potential energy than the reactants.
B)  This type of experiment will provide data to calculate ΔrU.
C)  The reaction is exothermic.
D)  Energy is leaving the system during the reaction.
E)  None of the above statements is true.

Question 9

A bomb calorimeter with a heat capacity of 13.9 kJ °C-1 has an initial temperature of 21.9 °C. If 5.00 g of propanal (C3H6O, molar mass = 58.0791 g mol-1,  Δ\DeltaΔ rU = -1822.7 kJ mol-1 for combustion) is combusted, calculate the final temperature of the calorimeter.

Accepted Answer

A)  26.1 °C
B)  16.7 °C
C)  33.2 °C
D)  43.1 °C
E)  34.0 °C

Question 10

At constant pressure, the combustion of 20.0 g of C2H6(g) releases 1036 kJ of heat. What is ΔH for the reaction given below? 2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(l)

Accepted Answer

A)  -173 kJ mol-1
B)  -779 kJ mol-1
C)  -1560 kJ mol-1
D)  -3120 kJ mol-1

Question 11

Identify the units of specific heat capacity.

Accepted Answer

A)  °C-1
B)  J g-1 °C-1
C)  J mol-1 °C-1
D)  g °C-1
E)  mol °C-1

Question 12

At 1.0133 bar, the heat of sublimation of gallium is 277 kJ mol-1 and the heat of vaporization is 271 kJ mol-1. To the correct number of significant figures, how much heat is required to melt 5.50 mol of gallium at 1.0133 bar?

Accepted Answer

A)  6 kJ
B)  33 kJ
C)  244 kJ
D)  274 kJ

Question 13

A 5.00 g sample of copper metal at 25.0 °C is heated by the addition of 96.0 J of energy. The final temperature of the copper is ________°C. The specific heat capacity of copper is 0.38 J g-1 K-1.

Accepted Answer

A)  32.3
B)  25.0
C)  25.5
D)  75.5
E)  50.5

Question 14

Use the ΔfH° and ΔrH° information provided to calculate ΔfH° for IF: ΔfH° (kJ mol-1)  IF7(g) + I2(g) → IF5(g) + 2IF(g) ΔrH° = -89 kJ
IF7(g)  -941
IF5(g)  -840

Accepted Answer

A)  101 kJ mol-1
B)  -146 kJ mol-1
C)  -190. kJ mol-1
D)  -95 kJ mol-1
E)  24 kJ mol-1

Question 15

Identify the greatest source of energy worldwide.

Accepted Answer

A)  petroleum
B)  natural gas
C)  wood
D)  coal
E)  nuclear power

Question 16

Identify the units of heat capacity.

Accepted Answer

A)  J °C-1
B)  J g-1 °C-1
C)  J mol-1 °C-1
D)  g °C-1
E)  mol °C-1

Question 17

Which of the following is NOT a standard state?

Accepted Answer

A)  for a solid, it is 25 °F
B)  for a liquid, it is 25 °C
C)  for a solution, it is 1 bar
D)  for a solution, it is 1 mol L-1
E)  for a liquid, it is 1 bar

Question 18

A piece of gold with a mass of 21.0 g was heated to 100.0 °C and placed inside a coffee cup calorimeter. The temperature of the water inside the calorimeter increased from 23.8 °C to 25.5 °C. The specific heat capacity of water is 4.184 J g-1 °C-1 and the specific heat capacity of gold is 0.129 J g-1 °C-1. Calculate the mass of water contained inside the calorimeter.

Accepted Answer

A)  28.4 g
B)  16.0 g
C)  21.0 g
D)  39.5 g
E)  32.9 g

Question 19

Use the ΔfH° information provided to calculate ΔrH° for the following: ΔfH° (kJ mol-1)   SO2Cl2 (g) + 2H2O(l) → 2HCl(g) + H2SO4(l) ΔrH° = ?
SO2Cl2(g) -364
H2O(l)  -286
HCl(g)  92
H2SO4(l) -814

Accepted Answer

A)  -256 kJ mol-1
B)  +161 kJ mol-1
C)  -62 kJ mol-1
D)  +800. kJ mol-1
E)  -422 kJ mol-1

Question 20

Calculate the change in internal energy (ΔU) for a system that is giving off 25.0 kJ of heat and is changing from 12.00 L to 6.00 L in volume at 1.50 bar. (Remember that 100 J = 1 L bar)

Accepted Answer

A)  +25.9 kJ
B)  -16.0 kJ
C)  -25.9 kJ
D)  -24.1 kJ
E)  937 kJ

Exam 6: Thermochemistry

Identify the greatest source of energy worldwide.

Correct Answer
verified

Correct Answer
verified

Identify a substance that is NOT in its standard state.

Correct Answer
verified

Identify the units of specific heat capacity.

Correct Answer
verified

Use the Δ_fH° information provided to calculate Δ_rH° for the following: Δ_fH°(kJ mol^-1) SO₂Cl₂ (g) + 2H₂O(l) → 2HCl(g) + H₂SO4(l) Δ_rH°= ? SO₂Cl₂(g) -364 H₂O(l) -286 HCl(g) 92 H₂SO₄(l) -814

Correct Answer
verified

Calculate the final temperature of 82.1 g of molecular hydrogen (specific heat capacity = 14.304 J g^-1 °C^-1) initially at 5.48 °C that absorbs 57 kJ of energy from the surroundings.

Correct Answer
verified

A 5.00 g sample of copper metal at 25.0 °C is heated by the addition of 96.0 J of energy. The final temperature of the copper is ________°C. The specific heat capacity of copper is 0.38 J g^-1 K^-1.

Correct Answer
verified

Define heat capacity.

Correct Answer
verified

At 1.0133 bar, the heat of sublimation of gallium is 277 kJ mol^-1 and the heat of vaporization is 271 kJ mol^-1. To the correct number of significant figures, how much heat is required to melt 5.50 mol of gallium at 1.0133 bar?

Correct Answer
verified

Use the Δ_fH° and Δ_rH° information provided to calculate Δ_fH° for IF: Δ_fH°(kJ mol^-1₎ IF₇(g) + I₂(g) → IF₅(g) + 2IF(g) Δ_rH°= -89 kJ IF₇(g) -941 IF₅(g) -840

Correct Answer
verified

According to the following thermochemical equation, what mass of H₂O (in g) must form to produce 975 kJ of energy? SiO₂(s) + 4HF(g) → SiF₄(g) + 2H₂O(l) Δ_rH°= -184 kJ

Correct Answer
verified

Two aqueous solutions are both at room temperature and are then mixed in a coffee cup calorimeter. The reaction causes the temperature of the resulting solution to fall below room temperature. Which of the following statements is TRUE?

Correct Answer
verified

Calculate the change in internal energy (ΔU) for a system that is giving off 25.0 kJ of heat and is changing from 12.00 L to 6.00 L in volume at 1.50 bar. (Remember that 100 J = 1 L bar)

Correct Answer
verified

Which of the following is NOT a standard state?

Correct Answer
verified

At constant pressure, the combustion of 20.0 g of C₂H₆(g) releases 1036 kJ of heat. What is ΔH for the reaction given below? 2C₂H₆(g) + 7O₂(g) → 4CO₂(g) + 6H₂O(l)

Correct Answer
verified

Match the following. -energy associated with the position of an object

Correct Answer
verified

Write the reaction illustrating Δ_fH° of CaCO₃ and draw the enthalpy diagram showing the relative positions of the reactants and products if it is an exothermic reaction.

Correct Answer
verified
Ca(s)+ C(s, graphite)+ 3/2 O₂(g...
View Answer

Identify the units of heat capacity.

Correct Answer
verified

10.618 g of an unknown salt is dissolved in a coffee cup calorimeter that contains 50.0 mL of water. The measured temperature decreased from 23.8 °C to 22.7 °C. Identify the unknown salt. The specific heat of water is 4.184 J g^-1 °C^-1, and assume the density of the solution is 1.00 g mL^-1.

Correct Answer
verified

A bomb calorimeter with a heat capacity of 13.9 kJ °C^-1 has an initial temperature of 21.9 °C. If 5.00 g of propanal (C₃H₆O, molar mass = 58.0791 g mol^-1, $\Delta$ _rU = -1822.7 kJ mol^-1 for combustion) is combusted, calculate the final temperature of the calorimeter.

Correct Answer
verified

Exam 6: Thermochemistry

Identify the greatest source of energy worldwide.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Identify a substance that is NOT in its standard state.

Correct AnswerverifiedShow Answer

Identify the units of specific heat capacity.

Correct AnswerverifiedShow Answer

Use the ΔfH° information provided to calculate ΔrH° for the following: ΔfH° (kJ mol-1) SO2Cl2 (g) + 2H2O(l) → 2HCl(g) + H2SO4(l) ΔrH° = ? SO2Cl2(g) -364 H2O(l) -286 HCl(g) 92 H2SO4(l) -814

Correct AnswerverifiedShow Answer

Calculate the final temperature of 82.1 g of molecular hydrogen (specific heat capacity = 14.304 J g-1 °C-1) initially at 5.48 °C that absorbs 57 kJ of energy from the surroundings.

Correct AnswerverifiedShow Answer

A 5.00 g sample of copper metal at 25.0 °C is heated by the addition of 96.0 J of energy. The final temperature of the copper is ________°C. The specific heat capacity of copper is 0.38 J g-1 K-1.

Correct AnswerverifiedShow Answer

Define heat capacity.

Correct AnswerverifiedShow Answer

At 1.0133 bar, the heat of sublimation of gallium is 277 kJ mol-1 and the heat of vaporization is 271 kJ mol-1. To the correct number of significant figures, how much heat is required to melt 5.50 mol of gallium at 1.0133 bar?

Correct AnswerverifiedShow Answer

Use the ΔfH° and ΔrH° information provided to calculate ΔfH° for IF: ΔfH° (kJ mol-1) IF7(g) + I2(g) → IF5(g) + 2IF(g) ΔrH° = -89 kJ IF7(g) -941 IF5(g) -840

Correct AnswerverifiedShow Answer

According to the following thermochemical equation, what mass of H2O (in g) must form to produce 975 kJ of energy? SiO2(s) + 4HF(g) → SiF4(g) + 2H2O(l) ΔrH° = -184 kJ

Correct AnswerverifiedShow Answer

Two aqueous solutions are both at room temperature and are then mixed in a coffee cup calorimeter. The reaction causes the temperature of the resulting solution to fall below room temperature. Which of the following statements is TRUE?

Correct AnswerverifiedShow Answer

Calculate the change in internal energy (ΔU) for a system that is giving off 25.0 kJ of heat and is changing from 12.00 L to 6.00 L in volume at 1.50 bar. (Remember that 100 J = 1 L bar)

Correct AnswerverifiedShow Answer

Which of the following is NOT a standard state?

Correct AnswerverifiedShow Answer

At constant pressure, the combustion of 20.0 g of C2H6(g) releases 1036 kJ of heat. What is ΔH for the reaction given below? 2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(l)

Correct AnswerverifiedShow Answer

Match the following. -energy associated with the position of an object

Correct AnswerverifiedShow Answer

Write the reaction illustrating ΔfH° of CaCO3 and draw the enthalpy diagram showing the relative positions of the reactants and products if it is an exothermic reaction.

Correct AnswerverifiedCa(s)+ C(s, graphite)+ 3/2 O2(g...View AnswerShow Answer

Identify the units of heat capacity.

Correct AnswerverifiedShow Answer

10.618 g of an unknown salt is dissolved in a coffee cup calorimeter that contains 50.0 mL of water. The measured temperature decreased from 23.8 °C to 22.7 °C. Identify the unknown salt. The specific heat of water is 4.184 J g-1 °C-1, and assume the density of the solution is 1.00 g mL-1.

Correct AnswerverifiedShow Answer

A bomb calorimeter with a heat capacity of 13.9 kJ °C-1 has an initial temperature of 21.9 °C. If 5.00 g of propanal (C3H6O, molar mass = 58.0791 g mol-1, Δ\DeltaΔ rU = -1822.7 kJ mol-1 for combustion) is combusted, calculate the final temperature of the calorimeter.

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Use the Δ_fH° information provided to calculate Δ_rH° for the following: Δ_fH°(kJ mol^-1) SO₂Cl₂ (g) + 2H₂O(l) → 2HCl(g) + H₂SO4(l) Δ_rH°= ? SO₂Cl₂(g) -364 H₂O(l) -286 HCl(g) 92 H₂SO₄(l) -814

Correct Answer
verified

Calculate the final temperature of 82.1 g of molecular hydrogen (specific heat capacity = 14.304 J g^-1 °C^-1) initially at 5.48 °C that absorbs 57 kJ of energy from the surroundings.

Correct Answer
verified

A 5.00 g sample of copper metal at 25.0 °C is heated by the addition of 96.0 J of energy. The final temperature of the copper is ________°C. The specific heat capacity of copper is 0.38 J g^-1 K^-1.

Correct Answer
verified

Correct Answer
verified

At 1.0133 bar, the heat of sublimation of gallium is 277 kJ mol^-1 and the heat of vaporization is 271 kJ mol^-1. To the correct number of significant figures, how much heat is required to melt 5.50 mol of gallium at 1.0133 bar?

Correct Answer
verified

Use the Δ_fH° and Δ_rH° information provided to calculate Δ_fH° for IF: Δ_fH°(kJ mol^-1₎ IF₇(g) + I₂(g) → IF₅(g) + 2IF(g) Δ_rH°= -89 kJ IF₇(g) -941 IF₅(g) -840

Correct Answer
verified

According to the following thermochemical equation, what mass of H₂O (in g) must form to produce 975 kJ of energy? SiO₂(s) + 4HF(g) → SiF₄(g) + 2H₂O(l) Δ_rH°= -184 kJ

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

At constant pressure, the combustion of 20.0 g of C₂H₆(g) releases 1036 kJ of heat. What is ΔH for the reaction given below? 2C₂H₆(g) + 7O₂(g) → 4CO₂(g) + 6H₂O(l)

Correct Answer
verified

Correct Answer
verified

Write the reaction illustrating Δ_fH° of CaCO₃ and draw the enthalpy diagram showing the relative positions of the reactants and products if it is an exothermic reaction.

Correct Answer
verified
Ca(s)+ C(s, graphite)+ 3/2 O₂(g...
View Answer

Correct Answer
verified

10.618 g of an unknown salt is dissolved in a coffee cup calorimeter that contains 50.0 mL of water. The measured temperature decreased from 23.8 °C to 22.7 °C. Identify the unknown salt. The specific heat of water is 4.184 J g^-1 °C^-1, and assume the density of the solution is 1.00 g mL^-1.

Correct Answer
verified

A bomb calorimeter with a heat capacity of 13.9 kJ °C^-1 has an initial temperature of 21.9 °C. If 5.00 g of propanal (C₃H₆O, molar mass = 58.0791 g mol^-1, $\Delta$ _rU = -1822.7 kJ mol^-1 for combustion) is combusted, calculate the final temperature of the calorimeter.

Correct Answer
verified