Question 1

Fuel values of hydrocarbons increase as the H/C atomic ratio increases. Which of the following compounds has the highest fuel value?

Accepted Answer

A) C2H6 
B) C2H4 
C) C2H2 
D) CH4 
E) C6H6 
A) C2H6 
B) C2H4 
C) C2H2 
D) CH4 
E) C6H6

Question 2

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 3.33 °C? (The specific heat of the solution is 3.74 J/g-K.)

Accepted Answer

A) -7.43 kJ 
B) -12.51 kJ 
C) 8.20 kJ 
D) -3.89 kJ 
E) 6.51 kJ 
A) -7.43 kJ 
B) -12.51 kJ 
C) 8.20 kJ 
D) -3.89 kJ 
E) 6.51 kJ

Question 3

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.

Accepted Answer

A) 4.78 
B) 33.5 
C) 62.5 
D) 10.5 
E) 286 
A) 4.78 
B) 33.5 
C) 62.5 
D) 10.5 
E) 286

Question 4

The value of ΔH° for the reaction below is +128.1 kJ: CH3OH (l) → CO (g) + 2H2 (g)
How many kJ of heat are consumed when 5.10 g of CO (g)is formed as shown in the equation?

Accepted Answer

A) 0.182 kJ 
B) 162 kJ 
C) 8.31 kJ 
D) 23.3 kJ 
E) 62.0 kJ 
A) 0.182 kJ 
B) 162 kJ 
C) 8.31 kJ 
D) 23.3 kJ 
E) 62.0 kJ

Question 5

Which of the following statements is false?

Accepted Answer

A) Internal energy is a state function. 
B) Enthalpy is an intensive property. 
C) The enthalpy change for a reaction is equal in magnitude, but opposite in sign, to the enthalpy change for the reverse reaction. 
D) The enthalpy change for a reaction depends on the state of the reactants and products. 
E) The enthalpy of a reaction is equal to the heat of the reaction. 
A) Internal energy is a state function. 
B) Enthalpy is an intensive property. 
C) The enthalpy change for a reaction is equal in magnitude, but opposite in sign, to the enthalpy change for the reverse reaction. 
D) The enthalpy change for a reaction depends on the state of the reactants and products. 
E) The enthalpy of a reaction is equal to the heat of the reaction.

Question 6

The value of ΔE for a system that performs 19 kJ of work on its surroundings and loses 9kJ of heat is ________ kJ.

Accepted Answer

A) -28 
B) 28 
C) 171 
D) 10 
E) -10 
A) -28 
B) 28 
C) 171 
D) 10 
E) -10

Question 7

Given the following reactions N2 (g) + O2 (g) → 2NO (g)ΔH = +180.7 kJ
2N2O (g) → O2 (g) + 2N2 (g)ΔH = -163.2 kJ
The enthalpy of reaction for
2N2O (g) → 2NO (g) + N2 (g)
Is ________ kJ.

Accepted Answer

A) 145.7 
B) 343.9 
C) -343.9 
D) 17.5 
E) -145.7 
A) 145.7 
B) 343.9 
C) -343.9 
D) 17.5 
E) -145.7

Question 8

Calculate the work (kJ)done during a reaction in which the internal volume contracts from 83 L to 13 L against an outside pressure of 4.4 atm.

Accepted Answer

A) 31 kJ 
B) 43 kJ 
C) -31 kJ 
D) -43 kJ 
E) 0 kJ; No work is done. 
A) 31 kJ 
B) 43 kJ 
C) -31 kJ 
D) -43 kJ 
E) 0 kJ; No work is done.

Question 9

Given the data in the table below, ΔH°rxn for the reaction Ag2O (s) + H2S (g) → Ag2S (s) + H2O (l)
Is ________ kJ.

Accepted Answer

A) -267 
B) -370 
C) -202 
D) -308 
E) More data are needed to complete the calculation. 
A) -267 
B) -370 
C) -202 
D) -308 
E) More data are needed to complete the calculation.

Question 10

The British thermal unit (Btu)is commonly used in engineering applications. A Btu is defined as the amount of heat required to raise the temperature of 1 lb of water by 1 °F. There are ________ Btu in one Joule. 1 lb = 453.59 g; °C = (5/9)(°F - 32°); specific heat of H2O (l)= 4.184 J/g-K.

Accepted Answer

A) 1056 Btu 
B) 1.896 × 10-3 Btu 
C) 9.278 × 10-4 Btu 
D) 5.120 × 10-3 Btu 
E) Additional information is needed to complete the calculation. 
A) 1056 Btu 
B) 1.896 × 10-3 Btu 
C) 9.278 × 10-4 Btu 
D) 5.120 × 10-3 Btu 
E) Additional information is needed to complete the calculation.

Question 11

Coal contains hydrocarbons of high molecular weight as well as compounds containing ________, oxygen, or nitrogen.

Accepted Answer

The answer of Coal contains hydrocarbons of high molecular weight...

Question 12

With reference to enthalpy changes, the term standard conditions means ________. (a)P = 1 atm
(b)some common temperature, usually 298 K
(c)V = 1 L

Accepted Answer

A) a only 
B) b only 
C) c only 
D) a and c 
E) a and b 
A) a only 
B) b only 
C) c only 
D) a and c 
E) a and b

Question 13

The internal energy can be increased by ________. (a)transferring heat from the surroundings to the system
(b)transferring heat from the system to the surroundings
(c)doing work on the system

Accepted Answer

A) a only 
B) b only 
C) c only 
D) a and c 
E) b and c 
A) a only 
B) b only 
C) c only 
D) a and c 
E) b and c

Question 14

Consider the following two reactions: A → 2B ΔH°rxn  = 456.7 kJ/mol
A → C ΔH°rxn  = -22.1 kJ/mol
Determine the enthalpy change for the process:
2B → C

Accepted Answer

A) -478.8 kJ/mol 
B) -434.6 kJ/mol 
C) 434.6 kJ/mol 
D) 478.8 kJ/mol 
E) More information is needed to solve the problem. 
A) -478.8 kJ/mol 
B) -434.6 kJ/mol 
C) 434.6 kJ/mol 
D) 478.8 kJ/mol 
E) More information is needed to solve the problem.

Question 15

For which one of the following reactions is ΔH°rxn equal to the heat of formation of the product?

Accepted Answer

A) N2 (g) + 3H2 (g) → 2NH3 (g) 
B) (1/2)N2 (g) + O2 (g) → NO2 (g) 
C) 6C (s) + 6H (g) → C6H6 (l) 
D) P (g) + 4H (g) + Br (g) → PH4Br (l) 
E) 12C (g) + 11H2 (g) + 11O (g) → C6H22O11 (g) 
A) N2 (g) + 3H2 (g) → 2NH3 (g) 
B) (1/2)N2 (g) + O2 (g) → NO2 (g) 
C) 6C (s) + 6H (g) → C6H6 (l) 
D) P (g) + 4H (g) + Br (g) → PH4Br (l) 
E) 12C (g) + 11H2 (g) + 11O (g) → C6H22O11 (g)

Question 16

Which one of the following statements is true?

Accepted Answer

A) Enthalpy is an intensive property. 
B) The enthalpy change for a reaction is independent of the state of the reactants and products. 
C) Enthalpy is a state function. 
D) H is the value of q measured under conditions of constant volume. 
E) The enthalpy change of a reaction is the reciprocal of the ΔH of the reverse reaction. 
A) Enthalpy is an intensive property. 
B) The enthalpy change for a reaction is independent of the state of the reactants and products. 
C) Enthalpy is a state function. 
D) H is the value of q measured under conditions of constant volume. 
E) The enthalpy change of a reaction is the reciprocal of the ΔH of the reverse reaction.

Question 17

Under what condition(s)is the enthalpy change of a process equal to the amount of heat transferred into or out of the system? (a)temperature is constant
(b)pressure is constant
(c)volume is constant

Accepted Answer

A) a only 
B) b only 
C) c only 
D) a and b 
E) b and c 
A) a only 
B) b only 
C) c only 
D) a and b 
E) b and c

Question 18

Given the data in the table below, ΔH°rxn for the reaction 2Ag2S (s) + O2 (g) → 2Ag2O (s) + 2S (s)
Is ________ kJ.

Accepted Answer

A) -1.6 
B) +1.6 
C) -3.2 
D) +3.2 
E) The ΔH°f of S (s)and of O2 (g)are needed for the calculation. 
A) -1.6 
B) +1.6 
C) -3.2 
D) +3.2 
E) The ΔH°f of S (s)and of O2 (g)are needed for the calculation.

Question 19

At what velocity (m/s)must a 19.9 g object be moving in order to possess a kinetic energy of 1.0 J?

Accepted Answer

A) 0.35 m/s 
B) 2.8 m/s 
C) 0.13 m/s 
D) 0.031 m/s 
E) 0.016 m/s 
A) 0.35 m/s 
B) 2.8 m/s 
C) 0.13 m/s 
D) 0.031 m/s 
E) 0.016 m/s

Question 20

The specific heat of liquid bromine is 0.226 J/g-K. How much heat (J)is required to raise the temperature of 10.0 mL of bromine from 25.00 °C to 27.30 °C? The density of liquid bromine: 3.12 g/mL.

Accepted Answer

A) 5.20 J 
B) 16.2 J 
C) 300 J 
D) 32.4 J 
E) 10.4 J 
A) 5.20 J 
B) 16.2 J 
C) 300 J 
D) 32.4 J 
E) 10.4 J

Exam 5: Thermochemistry

Fuel values of hydrocarbons increase as the H/C atomic ratio increases. Which of the following compounds has the highest fuel value?

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 3.33 °C? (The specific heat of the solution is 3.74 J/g-K.)

The value of ΔH° for the reaction below is +128.1 kJ: CH3OH (l) → CO (g) + 2H2 (g) How many kJ of heat are consumed when 5.10 g of CO (g)is formed as shown in the equation?

Which of the following statements is false?

The value of ΔE for a system that performs 19 kJ of work on its surroundings and loses 9kJ of heat is ________ kJ.

Given the following reactions N2 (g) + O2 (g) → 2NO (g)ΔH = +180.7 kJ 2N2O (g) → O2 (g) + 2N2 (g)ΔH = -163.2 kJ The enthalpy of reaction for 2N2O (g) → 2NO (g) + N2 (g) Is ________ kJ.

Calculate the work (kJ)done during a reaction in which the internal volume contracts from 83 L to 13 L against an outside pressure of 4.4 atm.

Given the data in the table below, ΔH°rxn for the reaction Ag2O (s) + H2S (g) → Ag2S (s) + H2O (l) Is ________ kJ.

The British thermal unit (Btu)is commonly used in engineering applications. A Btu is defined as the amount of heat required to raise the temperature of 1 lb of water by 1 °F. There are ________ Btu in one Joule. 1 lb = 453.59 g; °C = (5/9)(°F - 32°); specific heat of H2O (l)= 4.184 J/g-K.

Coal contains hydrocarbons of high molecular weight as well as compounds containing ________, oxygen, or nitrogen.

With reference to enthalpy changes, the term standard conditions means ________. (a)P = 1 atm (b)some common temperature, usually 298 K (c)V = 1 L

The internal energy can be increased by ________. (a)transferring heat from the surroundings to the system (b)transferring heat from the system to the surroundings (c)doing work on the system

Consider the following two reactions: A → 2B ΔH°rxn = 456.7 kJ/mol A → C ΔH°rxn = -22.1 kJ/mol Determine the enthalpy change for the process: 2B → C

For which one of the following reactions is ΔH°rxn equal to the heat of formation of the product?

Which one of the following statements is true?

Under what condition(s)is the enthalpy change of a process equal to the amount of heat transferred into or out of the system? (a)temperature is constant (b)pressure is constant (c)volume is constant

Given the data in the table below, ΔH°rxn for the reaction 2Ag2S (s) + O2 (g) → 2Ag2O (s) + 2S (s) Is ________ kJ.

At what velocity (m/s)must a 19.9 g object be moving in order to possess a kinetic energy of 1.0 J?

The specific heat of liquid bromine is 0.226 J/g-K. How much heat (J)is required to raise the temperature of 10.0 mL of bromine from 25.00 °C to 27.30 °C? The density of liquid bromine: 3.12 g/mL.

Introduction: Matter and Measurement

Atoms, Molecules, and Ions

Stoichiometry: Calculations With Chemical Formulas and Equations

Aqueous Reactions and Solution Stoichiometry

Electronic Structure of Atoms

Periodic Properties of the Elements

Basic Concepts of Chemical Bonding

Molecular Geometry and Bonding Theories

Gases

Liquids and Intermolecular Forces

Solids and Modern Materials

Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acid-Base Equilibria

Additional Aspects of Aqueous Equilibria

Chemistry of the Environment

Chemical Thermodynamics

Electrochemistry

Nuclear Chemistry

Chemistry of the Nonmetals

Transition Metals and Coordination Chemistry

The Chemistry of Life: Organic and Biological Chemistry

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The value of ΔH° for the reaction below is +128.1 kJ: CH₃OH (l) → CO (g) + 2H₂ (g) How many kJ of heat are consumed when 5.10 g of CO (g)is formed as shown in the equation?

Given the following reactions N₂ (g) + O₂ (g) → 2NO (g)ΔH = +180.7 kJ 2N₂O (g) → O₂ (g) + 2N₂ (g)ΔH = -163.2 kJ The enthalpy of reaction for 2N₂O (g) → 2NO (g) + N₂ (g) Is ________ kJ.

Given the data in the table below, ΔH°_rxn for the reaction Ag₂O (s) + H₂S (g) → Ag₂S (s) + H₂O (l) Is ________ kJ.

The British thermal unit (Btu)is commonly used in engineering applications. A Btu is defined as the amount of heat required to raise the temperature of 1 lb of water by 1 °F. There are ________ Btu in one Joule. 1 lb = 453.59 g; °C = (5/9)(°F - 32°); specific heat of H₂O (l)= 4.184 J/g-K.

Consider the following two reactions: A → 2B ΔH°_rxn = 456.7 kJ/mol A → C ΔH°_rxn = -22.1 kJ/mol Determine the enthalpy change for the process: 2B → C

For which one of the following reactions is ΔH°_rxn equal to the heat of formation of the product?

Given the data in the table below, ΔH°_rxn for the reaction 2Ag₂S (s) + O₂ (g) → 2Ag₂O (s) + 2S (s) Is ________ kJ.