Question 1

When Au is obtained by electrolysis from NaAu(CN)2,what is the minimum number of coulombs required to produce 1.26 mol of gold?

Accepted Answer

A) 6.08 × 104 C 
B) 1.22 × 105 C 
C) 2.43 × 105 C 
D) 3.65 × 105 C 
E) 4.86 × 105 C 
A) 6.08 × 104 C 
B) 1.22 × 105 C 
C) 2.43 × 105 C 
D) 3.65 × 105 C 
E) 4.86 × 105 C

Question 2

The following reactions take place in a lead storage battery.
Discharging: Pb(s)+ PbO2(s)+ 4H+(aq)+ 2SO42-(aq)→ 2PbSO4(s)+ 2H2O(l)
Charging: 2PbSO4(s)+ 2H2O(l)→ Pb(s)+ PbO2(s)+ 4H+(aq)+ 2SO42-(aq)
Which of the following statements is true?

Accepted Answer

A) The concentration of H2SO4 increases as the battery discharges. 
B) Pb is formed at the anode during discharge. 
C) Pb is formed at the cathode during charging. 
D) The mass of Pb decreases during charging. 
E) The mass of PbSO4 remains constant during charging and discharging. 
A) The concentration of H2SO4 increases as the battery discharges. 
B) Pb is formed at the anode during discharge. 
C) Pb is formed at the cathode during charging. 
D) The mass of Pb decreases during charging. 
E) The mass of PbSO4 remains constant during charging and discharging.

Question 3

Given:
Pb2+(aq)+ 2e-  Pb(s); E° = -0.13 V
Mg2+(aq)+ 2e-  Mg(s); E° = -2.38 V
Ag+(aq)+ e-  Ag(s); E° = 0.80 V
2H+(aq)+ 2e-  H2(g); E° = 0.00 V
Under standard-state conditions,which of the following species is the best reducing agent?

Accepted Answer

A) H2 
B) Mg2+ 
C) Ag+ 
D) Pb 
E) Ag 
A) H2 
B) Mg2+ 
C) Ag+ 
D) Pb 
E) Ag

Question 4

What mass of chromium could be deposited by electrolysis of an aqueous solution of Cr2(SO4)3 for 155 min using a constant current of 10.0 A? (F = 96485 C/mol)

Accepted Answer

A) 0.278 g 
B) 16.7 g 
C) 150.4 g 
D) 0.187 g 
E) 25.1 g 
A) 0.278 g 
B) 16.7 g 
C) 150.4 g 
D) 0.187 g 
E) 25.1 g

Question 5

When the following oxidation-reduction reaction in acidic solution is balanced,what is the lowest whole-number coefficient for Rb+(aq)?
Rb(s)+ Sr2+(aq)→ Rb+(aq)+ Sr(s)

Accepted Answer

A) 5 
B) 4 
C) 1 
D) 3 
E) 2 
A) 5 
B) 4 
C) 1 
D) 3 
E) 2

Question 6

Which of the following statements is true concerning the electrochemical cell described below at 25oC?
Ni | Ni2+(0.381M​)|| Ni2+(0.317M​)| Ni
​Ni2+ (aq​)+ 2e¯  ​Ni (s); ​E​º = -0.23 V

Accepted Answer

A) The cell reaction is spontaneous with a cell potential of 27.1 mV. 
B) The cell reaction is nonspontaneous with a cell potential of -0.23 V. 
C) The cell reaction is spontaneous with a cell potential of 2.36 mV. 
D) The cell reaction is nonspontaneous with a cell potential of 2.36 mV. 
E) The cell reaction is nonspontaneous with a cell potential of 27.1 mV. 
A) The cell reaction is spontaneous with a cell potential of 27.1 mV. 
B) The cell reaction is nonspontaneous with a cell potential of -0.23 V. 
C) The cell reaction is spontaneous with a cell potential of 2.36 mV. 
D) The cell reaction is nonspontaneous with a cell potential of 2.36 mV. 
E) The cell reaction is nonspontaneous with a cell potential of 27.1 mV.

Question 7

For a certain reaction,ΔHº = -75.4kJ and ΔSº = -225J/K.If ​n = ​3,calculate E°cell for the reaction at 25°C.

Accepted Answer

A) 0.0288 V 
B) 0.0961 V 
C) 0.241 V 
D) 0.492 V 
E) 0.0654 V 
A) 0.0288 V 
B) 0.0961 V 
C) 0.241 V 
D) 0.492 V 
E) 0.0654 V

Question 8

What is the cell reaction for the following electrochemical cell?
Cu | Cu2+(aq)|| Mn2+(aq)| Mn

Accepted Answer

A) 2Cu(s)+ Mn2+(aq)→ Mn(s)+ 2Cu2+(aq) 
B) Cu(s)+ Cu2+(aq)→ Mn(s)+ Mn2+(aq) 
C) Cu(s)+ Mn2+(aq)→ Mn(s)+ Cu2+(aq) 
D) 2Mn(s)+ Cu2+(aq)→ Cu(s)+ 2Mn2+(aq) 
E) Mn(s)+ Cu2+(aq)→ Cu(s)+ Mn2+(aq) 
A) 2Cu(s)+ Mn2+(aq)→ Mn(s)+ 2Cu2+(aq) 
B) Cu(s)+ Cu2+(aq)→ Mn(s)+ Mn2+(aq) 
C) Cu(s)+ Mn2+(aq)→ Mn(s)+ Cu2+(aq) 
D) 2Mn(s)+ Cu2+(aq)→ Cu(s)+ 2Mn2+(aq) 
E) Mn(s)+ Cu2+(aq)→ Cu(s)+ Mn2+(aq)

Question 9

For the cell Cu(s)|Cu2+||Ag+|Ag(s),the standard cell potential is 0.46 V.A cell using these reagents was made,and the observed potential was 0.29 V at 25oC.What is a possible explanation for the observed voltage?

Accepted Answer

A) The volume of the Cu2+ solution was larger than the volume of the Ag+ solution. 
B) The volume of the Ag+ solution was larger than the volume of the Cu2+ solution.​ 
C) The Cu2+ concentration was larger than the Ag+ concentration. 
D) The Ag electrode was twice as large as the Cu electrode. 
E) The Ag+ concentration was larger than the Cu2+ concentration. 
A) The volume of the Cu2+ solution was larger than the volume of the Ag+ solution. 
B) The volume of the Ag+ solution was larger than the volume of the Cu2+ solution.​ 
C) The Cu2+ concentration was larger than the Ag+ concentration. 
D) The Ag electrode was twice as large as the Cu electrode. 
E) The Ag+ concentration was larger than the Cu2+ concentration.

Question 10

For a certain oxidation-reduction reaction,E°cell is negative.This means that

Accepted Answer

A) ΔG° is positive and K is less than 1. 
B) ΔG° is negative and K is greater than 1. 
C) ΔG° is positive and K is greater than 1. 
D) ΔG° is negative and K is less than 1. 
E) ΔG° is zero and K is greater than 1. 
A) ΔG° is positive and K is less than 1. 
B) ΔG° is negative and K is greater than 1. 
C) ΔG° is positive and K is greater than 1. 
D) ΔG° is negative and K is less than 1. 
E) ΔG° is zero and K is greater than 1.

Question 11

When an aqueous solution of AgNO3 is electrolyzed,a gas is formed at the anode.What is the identity of the gas?
Reduction Half-Reaction
E° (V)
2H2O(l)+ 2e-  H2(g)+ 2OH-(aq) -0.83
2H+(aq)+ 2e-  H2(g) 0.00
Ag+(aq)+ e-  Ag(s) 0.80
NO3-(aq)+ 4H+(aq)+ 3e-  NO(g)+ 2H2O(l) 0.96
O2(g)+ 4H+(aq)+ 4e-  2H2O(l) 1.23

Accepted Answer

A) H2O 
B) NO 
C) Ag 
D) O2 
E) H2 
A) H2O 
B) NO 
C) Ag 
D) O2 
E) H2

Question 12

What reaction occurs at the anode during the electrolysis of aqueous CuSO4?
Reduction Half-Reaction
E° (V)
2H2O(l)+ 2e-  H2(g)+ 2OH-(aq) -0.83
2H+(aq)+ 2e-  H2(g) 0.00
Cu2+(aq)+ 2e-  Cu(s) 0.34
O2(g)+ 4H+(aq)+ 4e-  2H2O(l) 1.23

Accepted Answer

A) 2H2O(l)→ O2(g)+ 4H+(aq)+ 4e- 
B) Cu(s)→ Cu2+(aq)+ 2e- 
C) 2H2O(l)+ 2e- → H2(g)+ 2OH-(aq) 
D) Cu2+(aq)+ 2e- → Cu(s) 
E) 2H+(aq)+ 2e- → H2(g) 
A) 2H2O(l)→ O2(g)+ 4H+(aq)+ 4e- 
B) Cu(s)→ Cu2+(aq)+ 2e- 
C) 2H2O(l)+ 2e- → H2(g)+ 2OH-(aq) 
D) Cu2+(aq)+ 2e- → Cu(s) 
E) 2H+(aq)+ 2e- → H2(g)

Question 13

Cathodic protection results when

Accepted Answer

A) iron is amalgamated with mercury. 
B) iron is made amphoteric. 
C) iron is painted to protect it from corrosion. 
D) iron is tin-plated for use as a tin can. 
E) iron is attached to a more active metal. 
A) iron is amalgamated with mercury. 
B) iron is made amphoteric. 
C) iron is painted to protect it from corrosion. 
D) iron is tin-plated for use as a tin can. 
E) iron is attached to a more active metal.

Question 14

How many moles of electrons are produced from a current of 17.6 A in 3.20 h?

Accepted Answer

A) 3.35 mol 
B) 9.33 × 103 mol 
C) 5.84 × 10-4 mol 
D) 2.10 mol 
E) 56.3 mol 
A) 3.35 mol 
B) 9.33 × 103 mol 
C) 5.84 × 10-4 mol 
D) 2.10 mol 
E) 56.3 mol

Question 15

What is the correct cell notation for a cell in which the hydrogen electrode is the anode and the cathode half-reaction is Ce4+(aq)+ e− → Ce3+(aq).

Accepted Answer

A) Pt(s)| H2(g)| H+(aq)|| Ce4+(aq),Ce3+(aq)| Pt(s) 
B) Pt(s)| H2(g)| H+(aq)|| Ce4+(aq),Ce3+(aq) 
C) Ce3+(aq),Ce4+(aq)|| H+(aq)| H2(g)| Pt(s) 
D) Pt(s)| Ce3+(aq),Ce4+(aq)|| H+(aq)| H2(g)| Pt(s) 
E) H2(g)| H+(aq)|| Ce3+(aq),Ce4+(aq) 
A) Pt(s)| H2(g)| H+(aq)|| Ce4+(aq),Ce3+(aq)| Pt(s) 
B) Pt(s)| H2(g)| H+(aq)|| Ce4+(aq),Ce3+(aq) 
C) Ce3+(aq),Ce4+(aq)|| H+(aq)| H2(g)| Pt(s) 
D) Pt(s)| Ce3+(aq),Ce4+(aq)|| H+(aq)| H2(g)| Pt(s) 
E) H2(g)| H+(aq)|| Ce3+(aq),Ce4+(aq)

Question 16

A voltaic cell is made by placing an iron electrode in a compartment in which the Fe2+ concentration is 2.0 × 10-5 M and by placing a Pt electrode in the other compartment,in which the H+ concentration is 3.4 M and   = 1.00 atm.The Fe2+/Fe half-cell reduction potential is -0.41 V,and the H+/H2 half-cell reduction potential is 0.00 V.What is E for the cell at equilibrium?

Accepted Answer

A) -0.41 V 
B) 0.41 V 
C) 0.69 V 
D) 0.00 V 
E) 0.28 V 
A) -0.41 V 
B) 0.41 V 
C) 0.69 V 
D) 0.00 V 
E) 0.28 V

Question 17

Given:      
Cl2 (g)+ 2e¯  2Cl¯ (aq); E​º = 1.36V
What is  
For the following cell reaction?
2AlCl3(aq)  2Al(s)+ 3Cl2(g)

Accepted Answer

A) -5.8 × 105 J 
B) 5.8 × 105 J 
C)    
D) -1.7 × 106 J 
E) 1.7 × 106 J 
A) -5.8 × 105 J 
B) 5.8 × 105 J 
C)    
D) -1.7 × 106 J 
E) 1.7 × 106 J

Question 18

Calculate the solubility product of silver iodide at 25°C given the following data:
E°(V)
AgI(s)+ e- → Ag(s)+ I-
-0)15
I2(s)+ 2e- → 2I-
+0)54
Ag+ + e- → Ag(s)
+0)80

Accepted Answer

A) 2 × 10-12 
B) 3 × 10-3 
C) 2 × 10-24 
D) 9 × 10-17 
E) 2 × 10-4 
A) 2 × 10-12 
B) 3 × 10-3 
C) 2 × 10-24 
D) 9 × 10-17 
E) 2 × 10-4

Question 19

What is the logarithm of the equilibrium constant,log K,at 25°C of the voltaic cell constructed from the following two half-reactions?
Fe2+ (aq)+ 2e¯  Fe(s); ​E​° = - 0.41V
Ag+(aq)+ e-
   Ag(s); E° = 0.80 V

Accepted Answer

A) 6.7 
B) 40.9 
C) 20.3 
D) 13.2 
E) 67.6 
A) 6.7 
B) 40.9 
C) 20.3 
D) 13.2 
E) 67.6

Question 20

What is the reduction potential for the half-reaction Al3+(aq)+ 3e-   Al(s)at 25°C if [Al3+] = 0.18 M and E° = -1.66 V?

Accepted Answer

A) -1.66 V 
B) -1.65 V 
C) -1.84 V 
D) -1.72 V 
E) -1.67 V 
A) -1.66 V 
B) -1.65 V 
C) -1.84 V 
D) -1.72 V 
E) -1.67 V

Exam 19: Electrochemistry

When Au is obtained by electrolysis from NaAu(CN)2,what is the minimum number of coulombs required to produce 1.26 mol of gold?

The following reactions take place in a lead storage battery. Discharging: Pb(s)+ PbO2(s)+ 4H+(aq)+ 2SO42-(aq)→ 2PbSO4(s)+ 2H2O(l) Charging: 2PbSO4(s)+ 2H2O(l)→ Pb(s)+ PbO2(s)+ 4H+(aq)+ 2SO42-(aq) Which of the following statements is true?

Given: Pb2+(aq)+ 2e- Pb(s); E° = -0.13 V Mg2+(aq)+ 2e- Mg(s); E° = -2.38 V Ag+(aq)+ e- Ag(s); E° = 0.80 V 2H+(aq)+ 2e- H2(g); E° = 0.00 V Under standard-state conditions,which of the following species is the best reducing agent?

What mass of chromium could be deposited by electrolysis of an aqueous solution of Cr2(SO4)3 for 155 min using a constant current of 10.0 A? (F = 96485 C/mol)

When the following oxidation-reduction reaction in acidic solution is balanced,what is the lowest whole-number coefficient for Rb+(aq)? Rb(s)+ Sr2+(aq)→ Rb+(aq)+ Sr(s)

Which of the following statements is true concerning the electrochemical cell described below at 25oC? Ni | Ni2+(0.381M​)|| Ni2+(0.317M​)| Ni ​Ni2+ (aq​)+ 2e¯ ​Ni (s); ​E​º = -0.23 V

For a certain reaction,ΔHº = -75.4kJ and ΔSº = -225J/K.If ​n = ​3,calculate E°cell for the reaction at 25°C.

What is the cell reaction for the following electrochemical cell? Cu | Cu2+(aq)|| Mn2+(aq)| Mn

For the cell Cu(s)|Cu2+||Ag+|Ag(s),the standard cell potential is 0.46 V.A cell using these reagents was made,and the observed potential was 0.29 V at 25oC.What is a possible explanation for the observed voltage?

For a certain oxidation-reduction reaction,E°cell is negative.This means that

What reaction occurs at the anode during the electrolysis of aqueous CuSO4? Reduction Half-Reaction E° (V) 2H2O(l)+ 2e- H2(g)+ 2OH-(aq) -0.83 2H+(aq)+ 2e- H2(g) 0.00 Cu2+(aq)+ 2e- Cu(s) 0.34 O2(g)+ 4H+(aq)+ 4e- 2H2O(l) 1.23

Cathodic protection results when

How many moles of electrons are produced from a current of 17.6 A in 3.20 h?

What is the correct cell notation for a cell in which the hydrogen electrode is the anode and the cathode half-reaction is Ce4+(aq)+ e− → Ce3+(aq).

Given: Cl2 (g)+ 2e¯ 2Cl¯ (aq); E​º = 1.36V What is For the following cell reaction? 2AlCl3(aq) 2Al(s)+ 3Cl2(g)

Calculate the solubility product of silver iodide at 25°C given the following data: E°(V) AgI(s)+ e- → Ag(s)+ I- -0)15 I2(s)+ 2e- → 2I- +0)54 Ag+ + e- → Ag(s) +0)80

What is the logarithm of the equilibrium constant,log K,at 25°C of the voltaic cell constructed from the following two half-reactions? Fe2+ (aq)+ 2e¯ Fe(s); ​E​° = - 0.41V Ag+(aq)+ e- Ag(s); E° = 0.80 V

What is the reduction potential for the half-reaction Al3+(aq)+ 3e- Al(s)at 25°C if [Al3+] = 0.18 M and E° = -1.66 V?

Chemistry and Measurement

Atoms, molecules, and Ions

Calculations With Chemical Formulas and Equations

Chemical Reactions

The Gaseous State

Thermochemistry

Quantum Theory of the Atom

Electron Configurations and Periodicity

Ionic and Covalent Bonding

Molecular Geometry and Chemical Bonding Theory

States of Matter; Liquids and Solids

Solutions

Rates of Reaction

Chemical Equilibrium

Acids and Bases

Acid-Base Equilibria

Solubility and Complex-Ion Equilibria

Thermodynamics and Equilibrium

Nuclear Chemistry

Chemistry of the Main-Group Metals

The Transition Elements and Coordination Compounds

Organic Chemistry

Polymer Materials: Synthetic and Biological

Filters

When Au is obtained by electrolysis from NaAu(CN)₂,what is the minimum number of coulombs required to produce 1.26 mol of gold?

The following reactions take place in a lead storage battery. Discharging: Pb(s)+ PbO₂(s)+ 4H⁺(aq)+ 2SO₄^2-(aq)→ 2PbSO₄(s)+ 2H₂O(l) Charging: 2PbSO₄(s)+ 2H₂O(l)→ Pb(s)+ PbO₂(s)+ 4H⁺(aq)+ 2SO₄^2-(aq) Which of the following statements is true?

Given: Pb²⁺(aq)+ 2e^- Pb(s); E° = -0.13 V Mg²⁺(aq)+ 2e^- Mg(s); E° = -2.38 V Ag⁺(aq)+ e^- Ag(s); E° = 0.80 V 2H⁺(aq)+ 2e^- H₂(g); E° = 0.00 V Under standard-state conditions,which of the following species is the best reducing agent?

What mass of chromium could be deposited by electrolysis of an aqueous solution of Cr₂(SO₄)₃ for 155 min using a constant current of 10.0 A? (F = 96485 C/mol)

When the following oxidation-reduction reaction in acidic solution is balanced,what is the lowest whole-number coefficient for Rb⁺(aq)? Rb(s)+ Sr²⁺(aq)→ Rb⁺(aq)+ Sr(s)

Which of the following statements is true concerning the electrochemical cell described below at 25^oC? Ni | Ni²⁺(0.381M)|| Ni²⁺(0.317M)| Ni Ni²⁺ (aq)+ 2e¯ Ni (s); Eº = -0.23 V

For a certain reaction,ΔHº = -75.4kJ and ΔSº = -225J/K.If n = 3,calculate E°_cell for the reaction at 25°C.

What is the cell reaction for the following electrochemical cell? Cu | Cu²⁺(aq)|| Mn²⁺(aq)| Mn

For the cell Cu(s)|Cu²⁺||Ag⁺|Ag(s),the standard cell potential is 0.46 V.A cell using these reagents was made,and the observed potential was 0.29 V at 25^oC.What is a possible explanation for the observed voltage?

For a certain oxidation-reduction reaction,E°_cell is negative.This means that

What reaction occurs at the anode during the electrolysis of aqueous CuSO₄? Reduction Half-Reaction E° (V) 2H₂O(l)+ 2e^- H₂(g)+ 2OH^-(aq) -0.83 2H⁺(aq)+ 2e^- H₂(g) 0.00 Cu²⁺(aq)+ 2e^- Cu(s) 0.34 O₂(g)+ 4H⁺(aq)+ 4e^- 2H₂O(l) 1.23

What is the correct cell notation for a cell in which the hydrogen electrode is the anode and the cathode half-reaction is Ce⁴⁺(aq)+ e− → Ce³⁺(aq).

Given: Cl₂ (g)+ 2e¯ 2Cl¯ (aq); Eº = 1.36V What is For the following cell reaction? 2AlCl₃(aq) 2Al(s)+ 3Cl₂(g)

Calculate the solubility product of silver iodide at 25°C given the following data: E°(V) AgI(s)+ e^- → Ag(s)+ I^- -0)15 I₂(s)+ 2e^- → 2I^- +0)54 Ag⁺ + e^- → Ag(s) +0)80

What is the logarithm of the equilibrium constant,log K,at 25°C of the voltaic cell constructed from the following two half-reactions? Fe²⁺ (aq)+ 2e¯ Fe(s); E° = - 0.41V Ag⁺(aq)+ e^- Ag(s); E° = 0.80 V

What is the reduction potential for the half-reaction Al³⁺(aq)+ 3e^- Al(s)at 25°C if [Al³⁺] = 0.18 M and E° = -1.66 V?