Question 1

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.

Accepted Answer

A) 102 
B) 27.6 
C) 35.0 
D) 142 
E) 32.3 
A) 102 
B) 27.6 
C) 35.0 
D) 142 
E) 32.3 E

Question 2

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.

Accepted Answer

A) 450 
B) 330 
C) 790 
D) 99 
E) 260 
A) 450 
B) 330 
C) 790 
D) 99 
E) 260 A

Question 3

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?

Accepted Answer

A) -23.1 
B) -11.5 
C) -0.0217 
D) 1.44 
E) -2.31 × 104 
A) -23.1 
B) -11.5 
C) -0.0217 
D) 1.44 
E) -2.31 × 104 B

Question 4

Given the following reactions N2 (g)+ O2 (g)→ 2NO (g)ΔH = +180.7 kJ
2NO( g)+ O2 (g)→ 2NO2 (g)ΔH = -113.1 kJ
The enthalpy for the decomposition of nitrogen dioxide into molecular nitrogen and oxygen
2NO2 (g)→ N2 (g)+ 2 O2 (g)
Is __________ kJ.

Accepted Answer

A) 67.6 
B) -67.6 
C) 293.8 
D) -293.8 
E) 45.5 
A) 67.6 
B) -67.6 
C) 293.8 
D) -293.8 
E) 45.5

Question 5

Which one of the following is an exothermic process?

Accepted Answer

A) ice melting 
B) water evaporating 
C) boiling soup 
D) condensation of water vapor 
E) Ammonium thiocyanate and barium hydroxide are mixed at 25 °C: the temperature drops. 
A) ice melting 
B) water evaporating 
C) boiling soup 
D) condensation of water vapor 
E) Ammonium thiocyanate and barium hydroxide are mixed at 25 °C: the temperature drops.

Question 6

A chemical reaction that absorbs heat from the surroundings is said to be __________ and has a __________ ΔH at constant pressure.

Accepted Answer

A) endothermic, positive 
B) endothermic, negative 
C) exothermic, negative 
D) exothermic, positive 
E) exothermic, neutral 
A) endothermic, positive 
B) endothermic, negative 
C) exothermic, negative 
D) exothermic, positive 
E) exothermic, neutral

Question 7

For which one of the following reactions is the value of ΔH°rxn equal to ΔHf° for the product?

Accepted Answer

A) 2 C (s, graphite)+ 2 H2 (g)→ C2H4 (g) 
B) N2 (g)+ O2 (g)→ 2 NO (g) 
C) 2 H2 (g)+ O2 (g)→ 2 H2O (l) 
D) 2 H2 (g)+ O2 (g)→ 2 H2O (g) 
E) H2O (l)+ 1/2 O2 (g)→ H2O2 (l) 
A) 2 C (s, graphite)+ 2 H2 (g)→ C2H4 (g) 
B) N2 (g)+ O2 (g)→ 2 NO (g) 
C) 2 H2 (g)+ O2 (g)→ 2 H2O (l) 
D) 2 H2 (g)+ O2 (g)→ 2 H2O (g) 
E) H2O (l)+ 1/2 O2 (g)→ H2O2 (l)

Question 8

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 9

The most abundant fossil fuel is __________.

Accepted Answer

A) natural gas 
B) petroleum 
C) coal 
D) uranium 
E) hydrogen 
A) natural gas 
B) petroleum 
C) coal 
D) uranium 
E) hydrogen

Question 10

The value of ΔH° for the reaction below is -126 kJ. __________ kj are released when 2.00 mol of NaOH is formed in the reaction? 2 Na2O2 (s)+ 2 H2O (l)→ 4NaOH (s)+ O2 (g)

Accepted Answer

A) 252 
B) 63 
C) 3.9 
D) 7.8 
E) -126 
A) 252 
B) 63 
C) 3.9 
D) 7.8 
E) -126

Question 11

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 12

A chemical reaction that releases heat to the surroundings is said to be __________ and has a __________ ΔH at constant pressure.

Accepted Answer

A) endothermic, positive 
B) endothermic, negative 
C) exothermic, negative 
D) exothermic, positive 
E) exothermic, neutral 
A) endothermic, positive 
B) endothermic, negative 
C) exothermic, negative 
D) exothermic, positive 
E) exothermic, neutral

Question 13

Given the following reactions (1)2NO → N2 + O2 ΔH = -180 kJ
(2)2NO + O2 → 2NO2 ΔH = -112 kJ
The enthalpy of the reaction of nitrogen with oxygen to produce nitrogen dioxide
N2 + 2O2 → 2NO2
Is __________ kJ.

Accepted Answer

A) 68 
B) -68 
C) -292 
D) 292 
E) -146 
A) 68 
B) -68 
C) -292 
D) 292 
E) -146

Question 14

An 8.29 g sample of calcium carbonate [CaCO3 (s)] absorbs 50.3 J of heat, upon which the temperature of the sample increases from 21.1 °C to 28.5 °C. What is the specific heat of calcium carbonate?

Accepted Answer

A) .63 
B) .82 
C) 1.1 
D) 2.2 
E) 4.2 
A) .63 
B) .82 
C) 1.1 
D) 2.2 
E) 4.2

Question 15

Given the data in the table below, ΔH°rxn for the reaction SO3 (g)+ H2O (l)→ H2SO4 (l)
Is __________ kJ.

Accepted Answer

A) -132 
B) 1496 
C) 704 
D) -704 
E) -2.16 ×   
A) -132 
B) 1496 
C) 704 
D) -704 
E) -2.16 ×

Question 16

The value of ΔH° for the reaction below is -1107 kJ: 2Ba (s)+ O2 (g)→ 2BaO (s)
How many kJ of heat are released when 5.75 g of Ba (s)reacts completely with oxygen to form
BaO (s)?

Accepted Answer

A) 96.3 
B) 26.3 
C) 46.4 
D) 23.2 
E) 193 
A) 96.3 
B) 26.3 
C) 46.4 
D) 23.2 
E) 193

Question 17

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 18

The kinetic energy of a 12.5-g object moving at a speed of 81.9 m/s is __________ J.

Accepted Answer

A) 145 
B) 0.950 
C) 41.9 
D) 41900 
E) 1450 
A) 145 
B) 0.950 
C) 41.9 
D) 41900 
E) 1450

Question 19

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 20

Work equals force times distance.

Accepted Answer

A) True 
 B)False

Exam 5: Thermochemistry

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 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.

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?

Given the following reactions N2 (g)+ O2 (g)→ 2NO (g)ΔH = +180.7 kJ 2NO( g)+ O2 (g)→ 2NO2 (g)ΔH = -113.1 kJ The enthalpy for the decomposition of nitrogen dioxide into molecular nitrogen and oxygen 2NO2 (g)→ N2 (g)+ 2 O2 (g) Is __________ kJ.

Which one of the following is an exothermic process?

A chemical reaction that absorbs heat from the surroundings is said to be __________ and has a __________ ΔH at constant pressure.

For which one of the following reactions is the value of ΔH°rxn equal to ΔHf° for the product?

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

The most abundant fossil fuel is __________.

The value of ΔH° for the reaction below is -126 kJ. __________ kj are released when 2.00 mol of NaOH is formed in the reaction? 2 Na2O2 (s)+ 2 H2O (l)→ 4NaOH (s)+ O2 (g)

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

A chemical reaction that releases heat to the surroundings is said to be __________ and has a __________ ΔH at constant pressure.

Given the following reactions (1)2NO → N2 + O2 ΔH = -180 kJ (2)2NO + O2 → 2NO2 ΔH = -112 kJ The enthalpy of the reaction of nitrogen with oxygen to produce nitrogen dioxide N2 + 2O2 → 2NO2 Is __________ kJ.

An 8.29 g sample of calcium carbonate [CaCO3 (s)] absorbs 50.3 J of heat, upon which the temperature of the sample increases from 21.1 °C to 28.5 °C. What is the specific heat of calcium carbonate?

Given the data in the table below, ΔH°rxn for the reaction SO3 (g)+ H2O (l)→ H2SO4 (l) Is __________ kJ.

The value of ΔH° for the reaction below is -1107 kJ: 2Ba (s)+ O2 (g)→ 2BaO (s) How many kJ of heat are released when 5.75 g of Ba (s)reacts completely with oxygen to form BaO (s)?

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

The kinetic energy of a 12.5-g object moving at a speed of 81.9 m/s is __________ J.

Which of the following statements is false?

Work equals force times distance.

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

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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?

Given the following reactions N₂ (g)+ O₂ (g)→ 2NO (g)ΔH = +180.7 kJ 2NO( g)+ O₂ (g)→ 2NO₂ (g)ΔH = -113.1 kJ The enthalpy for the decomposition of nitrogen dioxide into molecular nitrogen and oxygen 2NO₂ (g)→ N₂ (g)+ 2 O₂ (g) Is __________ kJ.

A chemical reaction that absorbs heat from the surroundings is said to be and has a ΔH at constant pressure.

For which one of the following reactions is the value of ΔH°_rxn equal to ΔH_f° for the product?

The value of ΔH° for the reaction below is -126 kJ. __________ kj are released when 2.00 mol of NaOH is formed in the reaction? 2 Na₂O₂ (s)+ 2 H₂O (l)→ 4NaOH (s)+ O₂ (g)

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

A chemical reaction that releases heat to the surroundings is said to be and has a ΔH at constant pressure.

Given the following reactions (1)2NO → N₂ + O₂ ΔH = -180 kJ (2)2NO + O₂ → 2NO₂ ΔH = -112 kJ The enthalpy of the reaction of nitrogen with oxygen to produce nitrogen dioxide N₂ + 2O₂ → 2NO₂ Is __________ kJ.

An 8.29 g sample of calcium carbonate [CaCO₃ (s)] absorbs 50.3 J of heat, upon which the temperature of the sample increases from 21.1 °C to 28.5 °C. What is the specific heat of calcium carbonate?

Given the data in the table below, ΔH°_rxn for the reaction SO₃ (g)+ H₂O (l)→ H₂SO₄ (l) Is __________ kJ.

The value of ΔH° for the reaction below is -1107 kJ: 2Ba (s)+ O₂ (g)→ 2BaO (s) How many kJ of heat are released when 5.75 g of Ba (s)reacts completely with oxygen to form BaO (s)?