Question 1

All of the statements concerning free energy and spontaneity are true except

Accepted Answer

A) if the value of ΔG for a reaction is 55.2 kcal,the value of ΔG for the reverse reaction will be -55.2 kcal. 
B) if the value of ΔG for a reaction is negative,the reaction is said to be spontaneous. 
C) a reaction which is nonspontaneous at low temperature cannot be spontaneous at higher temperatures. 
D) enthalpy and entropy are of equal importance in determining the spontaneity of a reaction. 
E) the speed of a reaction is not influenced by its spontaneity. 
A) if the value of ΔG for a reaction is 55.2 kcal,the value of ΔG for the reverse reaction will be -55.2 kcal. 
B) if the value of ΔG for a reaction is negative,the reaction is said to be spontaneous. 
C) a reaction which is nonspontaneous at low temperature cannot be spontaneous at higher temperatures. 
D) enthalpy and entropy are of equal importance in determining the spontaneity of a reaction. 
E) the speed of a reaction is not influenced by its spontaneity.

Question 2

Consider the endothermic reaction:
N2(g)+ 2 H2(g)→ N2H4(l)
The entropy change of this reaction is ________ and the enthalpy change is ________,so at a very high temperature,this reaction is probably ________.

Accepted Answer

A) favorable;unfavorable;nonspontaneous 
B) favorable;unfavorable;spontaneous 
C) unfavorable;unfavorable;spontaneous 
D) unfavorable;unfavorable;nonspontaneous 
E) unfavorable;favorable;spontaneous 
A) favorable;unfavorable;nonspontaneous 
B) favorable;unfavorable;spontaneous 
C) unfavorable;unfavorable;spontaneous 
D) unfavorable;unfavorable;nonspontaneous 
E) unfavorable;favorable;spontaneous

Question 3

Match the following.
-A process or reaction which releases heat

Accepted Answer

A) exothermic 
B) activation energy 
C) chemical equilibrium 
D) endergonic 
E) exergonic
F)endothermic 
A) exothermic 
B) activation energy 
C) chemical equilibrium 
D) endergonic 
E) exergonic
F)endothermic

Question 4

Based on the bond energies given for each of the following which is the most stable?

Accepted Answer

A) O=O 498 kJ/mol 
B) C=O 745 kJ/mol 
C) C=C 614 kJ/mol 
D) C≡C 839 kJ/mol 
E) N≡N 946 kJ/mol 
A) O=O 498 kJ/mol 
B) C=O 745 kJ/mol 
C) C=C 614 kJ/mol 
D) C≡C 839 kJ/mol 
E) N≡N 946 kJ/mol

Question 5

A process or reaction which releases heat to the surroundings is said to be

Accepted Answer

A) conservative. 
B) endothermic. 
C) exothermic. 
D) isothermal. 
E) exergonic. 
A) conservative. 
B) endothermic. 
C) exothermic. 
D) isothermal. 
E) exergonic.

Question 6

To simplify comparisons,the energy value of fuels is expressed in units of

Accepted Answer

A) kcal. 
B) kcal/mol. 
C) kcal/g. 
D) kcal/L. 
E) some other unit. 
A) kcal. 
B) kcal/mol. 
C) kcal/g. 
D) kcal/L. 
E) some other unit.

Question 7

2 SO2(g)+ O2(g)  2 SO3(g)+ heat K = 4.8 ×  
Which statement about this system is not true?

Accepted Answer

A) At equilibrium  
Is the predominant substance. 
B) Heating the system will cause breakdown of  
. 
C) Adding  
Will cause an increase in the amount of
  
. 
D) Removing  
Will cause an increase in the amount of
  
. 
E) The large value of K means that the reaction essentially goes to completion. 
A) At equilibrium  
Is the predominant substance. 
B) Heating the system will cause breakdown of  
. 
C) Adding  
Will cause an increase in the amount of
  
. 
D) Removing  
Will cause an increase in the amount of
  
. 
E) The large value of K means that the reaction essentially goes to completion.

Question 8

Reaction rates are determined by all of the following factors except the

Accepted Answer

A) number of collisions between molecules. 
B) force of collisions between molecules. 
C) orientation of collisions between molecules. 
D) spontaneity of the reaction. 
E) activation energy of the reaction. 
A) number of collisions between molecules. 
B) force of collisions between molecules. 
C) orientation of collisions between molecules. 
D) spontaneity of the reaction. 
E) activation energy of the reaction.

Question 9

All of the statements are true for spontaneous reactions except

Accepted Answer

A) the value of ΔG is less than zero. 
B) the value of ΔG is unaffected by a catalyst. 
C) they are said to be exergonic. 
D) if the enthalpy change is unfavorable,they occur at a high temperature. 
E) the reaction rate is determined by the value of ΔG. 
A) the value of ΔG is less than zero. 
B) the value of ΔG is unaffected by a catalyst. 
C) they are said to be exergonic. 
D) if the enthalpy change is unfavorable,they occur at a high temperature. 
E) the reaction rate is determined by the value of ΔG.

Question 10

Consider the reaction:
2 CO(g)+ O2(g)  2 CO2(g)
The equilibrium expression for this reaction is:

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 11

Based on the reaction shown,which statement is true?
S + O2 → SO2 + 70.8 kcal

Accepted Answer

A) 70.8 kcal are produced when 1 g of sulfur reacts. 
B) 70.8 kcal are consumed when 1 g of sulfur reacts. 
C) 70.8 kcal are produced when 32.1 g of sulfur reacts. 
D) 70.8 kcal are consumed when 32.1 g of sulfur reacts. 
E) 70.8 kcal are produced when 1 g of sulfur dioxide is produced. 
A) 70.8 kcal are produced when 1 g of sulfur reacts. 
B) 70.8 kcal are consumed when 1 g of sulfur reacts. 
C) 70.8 kcal are produced when 32.1 g of sulfur reacts. 
D) 70.8 kcal are consumed when 32.1 g of sulfur reacts. 
E) 70.8 kcal are produced when 1 g of sulfur dioxide is produced.

Question 12

Which process is not likely to be considered reversible?

Accepted Answer

A) a round trip to Las Vegas 
B) melting wax to make candles 
C) a reaction using the symbol "↔" 
D) cutting down a tree 
E) dissolving salt in water 
A) a round trip to Las Vegas 
B) melting wax to make candles 
C) a reaction using the symbol "↔" 
D) cutting down a tree 
E) dissolving salt in water

Question 13

If we add a catalyst to the following equation,CO + H2O + heat  CO2 + H2,which way will the equilibrium shift?

Accepted Answer

A) to the left 
B) no effect 
C) to the right 
D) not enough information 
A) to the left 
B) no effect 
C) to the right 
D) not enough information

Question 14

Which factors would increase the rate of a chemical reaction?
I.Increasing the temperature
II.Removing products as they are formed
III.Adding a catalyst

Accepted Answer

A) I and II 
B) II and III 
C) I,II,and III 
D) I only 
E) II only 
A) I and II 
B) II and III 
C) I,II,and III 
D) I only 
E) II only

Question 15

The label on a package of cookies states that there are 100 calories per serving.Explain the different meanings of this statement to a chemist and to a nutritionist.Be sure your answer explains the difference between kilocalories and Calorie.

Accepted Answer

This statement means that the food energ

Question 16

If heat is consumed during a reaction,the reaction is said to be

Accepted Answer

A) endothermic. 
B) exothermic. 
C) endergonic. 
D) energetic. 
E) can't tell. 
A) endothermic. 
B) exothermic. 
C) endergonic. 
D) energetic. 
E) can't tell.

Question 17

For the reaction given below,what quantity of heat will be produced if 90.0 g of C3H8 are consumed in the reaction?
C3H8 + 5 O2 → 3 CO2 + 4 H2O + 488 kcal

Accepted Answer

A) 996 kcal 
B) 488 kcal 
C) 332 kcal 
D) 239 kcal 
E) 976 kcal 
A) 996 kcal 
B) 488 kcal 
C) 332 kcal 
D) 239 kcal 
E) 976 kcal

Question 18

Consider the reaction:
A + 2 B  2 C + D
The equilibrium expression for this reaction is:

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 19

The concept of free energy allows prediction of spontaneity of a process by considering the changes in ________ and ________ during the process.

Accepted Answer

A) enthalpy;entropy 
B) enthalpy;mass 
C) entropy;mass 
D) enthalpy;temperature 
E) entropy;temperature 
A) enthalpy;entropy 
B) enthalpy;mass 
C) entropy;mass 
D) enthalpy;temperature 
E) entropy;temperature

Question 20

Calculate the enthalpy for the combustion of propane shown using the given bond dissociation energies:
C3H8 + 5 O2 → 3 CO2 + 4H2O
Number and types of bonds in each molecule:
C3H8 (2 C-C,8 C-H bonds);O2 (1 O=O); (2 C=O bonds); (2 O-H bonds).
Bond dissociation energies:
C-C (347 kJ/mol);C-H (413 kJ/mol);O=O (498 kJ/mol;C=O (799 kJ/mol);O-H (467 kJ/mol)

Accepted Answer

A) -1962 kJ 
B) 1962 kJ 
C) -2042 kJ 
D) -50 kJ 
E) -1242 kJ 
A) -1962 kJ 
B) 1962 kJ 
C) -2042 kJ 
D) -50 kJ 
E) -1242 kJ

Exam 7: Chemical Reactions: Energy, rates, and Equilibrium

All of the statements concerning free energy and spontaneity are true except

Consider the endothermic reaction: N2(g)+ 2 H2(g)→ N2H4(l) The entropy change of this reaction is ________ and the enthalpy change is ________,so at a very high temperature,this reaction is probably ________.

Match the following. -A process or reaction which releases heat

Based on the bond energies given for each of the following which is the most stable?

A process or reaction which releases heat to the surroundings is said to be

To simplify comparisons,the energy value of fuels is expressed in units of

2 SO2(g)+ O2(g) 2 SO3(g)+ heat K = 4.8 × Which statement about this system is not true?

Reaction rates are determined by all of the following factors except the

All of the statements are true for spontaneous reactions except

Consider the reaction: 2 CO(g)+ O2(g) 2 CO2(g) The equilibrium expression for this reaction is:

Based on the reaction shown,which statement is true? S + O2 → SO2 + 70.8 kcal

Which process is not likely to be considered reversible?

If we add a catalyst to the following equation,CO + H2O + heat CO2 + H2,which way will the equilibrium shift?

Which factors would increase the rate of a chemical reaction? I.Increasing the temperature II.Removing products as they are formed III.Adding a catalyst

The label on a package of cookies states that there are 100 calories per serving.Explain the different meanings of this statement to a chemist and to a nutritionist.Be sure your answer explains the difference between kilocalories and Calorie.

If heat is consumed during a reaction,the reaction is said to be

For the reaction given below,what quantity of heat will be produced if 90.0 g of C3H8 are consumed in the reaction? C3H8 + 5 O2 → 3 CO2 + 4 H2O + 488 kcal

Consider the reaction: A + 2 B 2 C + D The equilibrium expression for this reaction is:

The concept of free energy allows prediction of spontaneity of a process by considering the changes in ________ and ________ during the process.

Matter and Measurements

Atoms and the Periodic Table

Ionic Compounds

Molecular Compounds

Classification and Balancing of Chemical Reactions

Chemical Reactions: Mole and Mass Relationships

Gases, liquids, and Solids

Solutions

Acids and Bases

Nuclear Chemistry

Introduction to Organic Chemistry: Alkanes

Alkenes, alkynes, and Aromatic Compounds

Some Compounds With Oxygen, sulfur, or a Halogen

Aldehydes and Ketones

Amines

Carboxylic Acids and Their Derivatives

Amino Acids and Proteins

Enzymes and Vitamins

Carbohydrates

The Generation of Biochemical Energy

Carbohydrate Metabolism

Lipids

Lipid Metabolism

Protein and Amino Acid Metabolism

Nucleic Acids and Protein Synthesis

Genomics

Chemical Messengers: Hormones, neurotransmitters, and Drugs

Body Fluids

Filters

Consider the endothermic reaction: N₂(g)+ 2 H₂(g)→ N₂H₄(l) The entropy change of this reaction is and the enthalpy change is ,so at a very high temperature,this reaction is probably .

2 SO₂(g)+ O₂(g) 2 SO₃(g)+ heat K = 4.8 × Which statement about this system is not true?

Consider the reaction: 2 CO(g)+ O₂(g) 2 CO₂(g) The equilibrium expression for this reaction is:

Based on the reaction shown,which statement is true? S + O₂ → SO₂ + 70.8 kcal

If we add a catalyst to the following equation,CO + H₂O + heat CO₂ + H₂,which way will the equilibrium shift?

For the reaction given below,what quantity of heat will be produced if 90.0 g of C₃H₈ are consumed in the reaction? C₃H₈ + 5 O₂ → 3 CO₂ + 4 H₂O + 488 kcal

The concept of free energy allows prediction of spontaneity of a process by considering the changes in and during the process.