1

In which reaction is iron reduced?

A. iron(III) oxide reacting with carbon monoxide to form liquid iron and carbon dioxide 

B. iron(II) chloride reacting with potassium nitrate and hydrochloric acid to form nitric oxide (NO), iron(III) chloride, potassium chloride and water   

C. iron(II) nitrate reacting with sodium hydroxide to form iron(II) hydroxide and sodium nitrate

D. iron reacting with nitric acid to form iron(II) nitrate and hydrogen gas               

E. iron reacting with nickel(II) chloride to form iron(II) chloride and nickel             

F. iron(III) acetate reacting with potassium sulfide to form iron(III) sulfide and potassium acetate            

2

In which reaction is nitrogen reduced?

A. iron(II) chloride reacting with potassium nitrate and hydrochloric acid to form nitric oxide (NO), iron(III) chloride, potassium chloride and water   

B. nitrogen reacting with hydrogen to form ammonia    

C. copper(II) nitrate reacting with potassium sulfide to form the precipitate copper(II) sulfide and aqueous potassium nitrate           

D. nitrous acid reacting with potassium hydroxide to form potassium nitrite and water  

E. iron reacting with nitric acid to form iron(II) nitrate and hydrogen gas

F. iron(II) nitrate reacting with sodium hydroxide to form iron(II) hydroxide and sodium nitrate

3

Which reactions are redox reactions?

Choose at least one answer.

A. hydrochloric acid reacting with nickel metal to form hydrogen gas and aqueous nickel(II) chloride       

B. sodium bromide reacting with chlorine to form sodium chloride and bromine               

C. sodium hydroxide reacting with aluminum chloride to form solid aluminum hydroxide and sodium chloride    

D. sodium hydroxide reacting with hydrochloric acid to form water and sodium chloride               

E. sodium hydroxide reacting with potassium to form potassium hydroxide and sodium

F. acetic acid reacting with sodium bicarbonate to form carbon dioxide, water and sodium acetate          

4

Which substance is the strongest oxidizing agent?

A. Ag⁺   

B. Sn²⁺  

C. Ni²⁺  

D. Fe²⁺ 

E. Cr³⁺   

F. Na⁺   

5

Which substance is the strongest reducing agent?

A. Mg   

B. Al      

C. Cd     

D. Fe     

E. Pb     

F. H₂     

6

How many electrons are transferred in the redox reaction taking place in acidic solution:

Sn²⁺(aq) + Cr₂O₇^2-(aq) → Cr³⁺(aq) + Sn⁴⁺(aq)?

7

How many electrons are transferred in the redox reaction taking place in basic solution:

Cr(s) + ClO₄^-(aq) → ClO₃^-(aq) + Cr³⁺(aq)?

8

How many electrons are transferred in the redox reaction:

Pb²⁺(aq) + Ni(s) → Pb(s) + Ni²⁺(aq)?

9

How many electrons are transferred in the redox reaction:

Zn(s) + Fe³⁺(aq) → Zn²⁺(aq) + Fe(s)?

10

What is the stoichiometric coefficient for the hydrogen ion in the balanced redox reaction of:

Cl^-(aq) + NO₃^-(aq) → NO(g) + Cl₂(g) when balanced in acidic solution?

11

What is the stoichiometric coefficient for the hydrogen ion in the balanced redox reaction of:

Zn(s) + NO₃^-(aq) → NO₂(g) + Zn²⁺(aq) when balanced in acidic solution?

12

What is the stoichiometric coefficient for the hydroxide ion in the balanced redox reaction of:

In⁺(aq) + ClO^-(aq) → Cl^-(aq) + In³⁺(aq) when balanced in basic solution?

13

What is the stoichiometric coefficient for the hydroxide ion in the balanced redox reaction of:

Cr(s) + ClO₄^-(aq) → ClO₃^-(aq) + Cr³⁺(aq) when balanced in basic solution?

14

What is the stoichiometric coefficient for the hydroxide ion in the balanced redox reaction of:

Na(s) + H₂O(l) → Na⁺(aq) + H₂(g) when balanced in basic solution?

15

What is the stoichiometric coefficient for the substance oxidized (as a reactant) in the balanced redox reaction of:

Fe(s) + MnO₄^-(aq) → Mn²⁺(aq) + Fe³⁺(aq) when balanced in acidic solution?

16

What is the stoichiometric coefficient for the substance oxidized (as a reactant) in the balanced redox reaction of:

Pb(s) + MnO₄^2-(aq) → MnO₂(s) + Pb²⁺(aq) when balanced in basic solution?

17

What is the stoichiometric coefficient for the substance reduced (as a reactant) in the balanced redox reaction of:

Fe(s) + MnO₄^-(aq) → Mn²⁺(aq) + Fe³⁺(aq) when balanced in acidic solution?

18

What is the stoichiometric coefficient for the substance reduced (as a reactant) in the balanced redox reaction of:

Pb(s) + MnO₄^2-(aq) → MnO₂(s) + Pb²⁺(aq) when balanced in basic solution?

19

What is the stoichiometric coefficient for water in the balanced redox reaction of:

In⁺(aq) + ClO^-(aq) → Cl^-(aq) + In³⁺(aq) when balanced in basic solution?

20

What is the stoichiometric coefficient for water in the balanced redox reaction of:

Cr(s) + ClO₄^-(aq) → ClO₃^-(aq) + Cr³⁺(aq) when balanced in basic solution?

21

Using Appendix 2 in your textbook, what is the standard change in entropy (in J/K) at 25^oC of the reaction:

2NO(g) + N₂(g) → 2N₂O(g)?

22

Using Appendix 2 in your textbook, what is the standard change in entropy (in J/K) at 25^oC of the reaction:

2O₃(g) → 3O₂(g)?

23

What is the sign on the change in entropy for the process: 2N2(g) + O₂(g)→ 2N₂O(g)

a. entropy is increasing 

b. entropy is unchanged              

c. entropy is decreasing               

d. entropy cannot be approximated       

24

What is the sign on the change in entropy for the process: 2N₂O₅(g)→ 4NO₂(g) + O₂(g)

a. entropy is increasing 

b. entropy is unchanged              

c. entropy is decreasing               

d. entropy cannot be approximated       

25

What is the sign on the change in entropy for the process: Cgraphite(s) at 0^oC → Cgraphite(s) at 25^oC

a. entropy is increasing 

b. entropy is unchanged              

c. entropy is decreasing               

d. entropy cannot be approximated       

26

What is the sign on the change in entropy for the process: H₂O(g) → H₂O(l)

a. entropy is increasing 

b. entropy is unchanged              

c. entropy is decreasing               

d. entropy cannot be approximated       

27

What is the sign on the change in entropy for the process: KBr(s) → K⁺(aq) + Br^-(aq)

a. entropy is increasing 

b. entropy is unchanged              

c. entropy is decreasing               

d. entropy cannot be approximated       

28

What is the sign on the change in entropy for the process: PCl₅(g) → PCl₃(g) + Cl₂(g)

a. entropy is increasing 

b. entropy is unchanged              

c. entropy is decreasing               

d. entropy cannot be approximated       

29

What is the order of the lowest entropy (1 = lowest) to highest entropy (3 = highest)?

H₂O(g)  2 = moderate     1 = lowest           3 = highest

H₂O(l)    2 = moderate     1 = lowest           3 = highest

H₂O(s)   2 = moderate     1 = lowest           3 = highest

30

What is the order of the lowest entropy (1 = lowest) to highest entropy (3 = highest)?

Br₂(g)    3 = highest          2 = moderate     1 = lowest

Cl₂(g)     3 = highest          2 = moderate     1 = lowest

F₂(g)      3 = highest          2 = moderate     1 = lowest

31

What is the order of the lowest entropy (1 = lowest) to highest entropy (3 = highest)?

C₂H₄(g)

1 = lowest           3 = highest          2 = moderate

C₃H₆(g) 1 = lowest           3 = highest          2 = moderate

C₄H₈(g) 1 = lowest           3 = highest          2 = moderate

32

What combination will always result in a spontaneous process?

a. The entropy of the system increases and the entropy of the surroundings decreases.              

b. The entropy of the system decreases but the entropy of the surroundings increases.               

c. The entropy of the system increases but the entropy of the surroundings decreases.               

d. The entropy of the system increases and the entropy of the surroundings increases.

33

What is the second law of thermodynamics?

a. The entropy of the universe is constant for a spontaneous process.   

b. The entropy of the universe increases for a spontaneous process.     

c. The entropy of the universe decreases for a spontaneous process.    

d. The entropy of the universe is zero for a spontaneous process.           

34

What will result is a process being spontaneous?

(More than one answer can be correct - each correct answer will result in full credit)

a. Both the change in entropy of the system and the change in entropy of the surroundings are greater than zero.               

b. Both the change in entropy of the system and the change in entropy of the surroundings are less than zero.

c. The change in entropy of the system is greater than zero while the change in entropy of the surroundings is less than zero and the change in entropy of the system is greater in magnitude than the change in entropy of the surroundings.               

d. The change in entropy of the system is greater than zero while the change in entropy of the surroundings is less than zero and the change in entropy of the system is lower in magnitude than the change in entropy of the surroundings.               

35

Which describes an endothermic system in which the entropy of the universe is increasing (spontaneous)?

a. Enthalpy of the surroundings decreases and the entropy of the system decreases     

b. Enthalpy of the surroundings decreases and the entropy of the system increases       

c. Enthalpy of the surroundings increases and the entropy of the system decreases       

d. Enthalpy of the surroundings increases and the entropy of the system increases        

36

For the reaction, 2CO(g) + O₂(g) → 2CO₂(g), which statement is true?

a. This reaction is always spontaneous. 

b. This reaction is never spontaneous.  

c. This reaction is spontaneous at low temperatures and not spontaneous at high temperatures.             

d. This reaction is not spontaneous at low temperatures and spontaneous at high temperatures.            

37

Using Appendix 2 in your textbook, at what temperature (in K) will the reaction, 2CO(g) + O₂(g) → 2CO₂(g), change in spontaneity?

Assume standard change in enthalpy and standard change in entropy do not change with temperature.

38

Using Appendix 2 in your textbook, what is the value for the standard change in Gibbs free energy (in kJ) at 25^oC of the reaction:

2C₆H₆(l) + 15O₂(g) → 12CO₂(g) + 6H₂O(l)?

39

Using Appendix 2 in your textbook, what is the value for the standard change in Gibbs free energy (in kJ) at 25^oC of the reaction:

2NO(g) + N₂(g) → 2N₂O(g)?

40

Using Appendix 2 in your textbook, what is the value for the standard change in Gibbs free energy (in kJ) at 25^oC of the reaction:

2O₃(g) → 3O₂(g)?

41

Using Appendix 2 in your textbook, what is the value for the standard change in Gibbs free energy (in kJ) at 25^oC of the reaction:

C₂H₄(g) + H₂(g) → C₂H₆(g)?

42

What is the value for the standard change in Gibbs free energy (in kJ), when the standard change in enthalpy is (-571.8) kJ and the standard change in entropy is (-149.73) J/K at 25^oC?

43

What is the value for the standard change in Gibbs free energy (in kJ), when the standard change in enthalpy is 559.7 kJ and the standard change in entropy is 130.62 J/K at 25^oC?

44

Which combination will result in a system that is always spontaneous?

a. ΔHsys< 0 and ΔSsys< 0             

b. ΔHsys< 0 and ΔSsys> 0            

c. ΔHsys> 0 and ΔSsys< 0             

d. ΔHsys> 0 and ΔSsys> 0            

45

Which combination will result in a system that is never spontaneous?

a. ΔHsys< 0 and ΔSsys< 0             

b. ΔHsys< 0 and ΔSsys> 0            

c. ΔHsys> 0 and ΔSsys< 0             

d. ΔHsys> 0 and ΔSsys> 0            

46

Which combination will result in a system that is spontaneous at high temperatures only?

a. ΔHsys< 0 and ΔSsys< 0             

b. ΔHsys< 0 and ΔSsys> 0            

c. ΔHsys> 0 and ΔSsys< 0             

d. ΔHsys> 0 and ΔSsys> 0            

47

Which combination will result in a system that is spontaneous at low temperatures only?

a. ΔHsys< 0 and ΔSsys< 0             

b. ΔHsys< 0 and ΔSsys> 0            

c. ΔHsys> 0 and ΔSsys< 0             

d. ΔHsys> 0 and ΔSsys> 0            

48

Given the Ka of benzoic acid from Chapter 16 in your textbook, what is the value of change in Gibbs free energy (in kJ/mol) at 25^oC for this process?

49

Given the Kb of urea from Chapter 16 in your textbook, what is the value of change in Gibbs free energy (in kJ/mol) at 25^oC for this process?

50

Given the Ksp of cobalt(II) sulfide from Chapter 17 in your textbook, what is the value of change in Gibbs free energy (in kJ/mol) at 25^oC for this process?

51

Given the Kw of water from Chapter 16 in your textbook, what is the value of change in Gibbs free energy (in kJ/mol) at 25^oC for this process?

52

What is true for a spontaneous process?

a. ΔGsys< 0 and K < 1    

b. ΔGsys> 0 and K < 1    

c. ΔGsys< 0 and K > 1     

d. ΔGsys> 0 and K > 1    

53

When ΔGo > 0 and Q>K,

a. ΔG > 0 and the reaction will shift to the right.

b. ΔG > 0 and the reaction will shift to the left.  

c. ΔG < 0 and the reaction will shift to the right.

d. ΔG < 0 and the reaction will shift to the left.  

54

When ΔGo < 0 and Q

a. ΔG > 0 and the reaction will shift to the right.

b. ΔG > 0 and the reaction will shift to the left.  

c. ΔG < 0 and the reaction will shift to the right.

d. ΔG < 0 and the reaction will shift to the left.  

55

When ΔGo < 0 and the system is at equilibrium,

a. ΔG = 0 and Q = K.       

b. ΔG = 0 and Q = 0.       

c. ΔG = ΔGo and Q = K. 

d. ΔG = ΔGo and Q = 0. 

56

In the reaction of bromine with potassium iodide to produce potassium bromide and iodine, what is reduced and what is the reducing agent?

A. bromine is reduced and potassium iodide is the reducing agent           

B. bromine is reduced and bromine is the reducing agent            

C. iodine is reduced and potassium iodide is the reducing agent

D. iodine is reduced and bromine is the reducing agent 

E. potassium is reduced and potassium iodide is the reducing agent        

F. potassium is reduced and bromine is the reducing agent         

57

In the reaction of sodium with water to produce sodium hydroxide and hydrogen gas, what is reduced and what is the reducing agent?

A. hydrogen is reduced and sodium is the reducing agent            

B. hydrogen is reduced and water is the reducing agent               

C. sodium is reduced and sodium is the reducing agent 

D. sodium is reduced and water is the reducing agent    

E. oxygen is reduced and sodium is the reducing agent 

F. oxygen is reduced and water is the reducing agent