Question 1

Choose the INCORRECT statement.

Accepted Answer

A) A cell diagram is a symbolic way to show cell components. 
B) An anode is where oxidation occurs. 
C) A cathode is where reduction occurs. 
D) Half cells in a cell diagram are separated by a single vertical line. 
E) The anode is on the left in a cell diagram. 
A) A cell diagram is a symbolic way to show cell components. 
B) An anode is where oxidation occurs. 
C) A cathode is where reduction occurs. 
D) Half cells in a cell diagram are separated by a single vertical line. 
E) The anode is on the left in a cell diagram.

Question 2

What mass of silver can be deposited by the passage of a constant current of 5.00 A through a AgNO3(aq)solution for 2.00 hours?

Accepted Answer

A) 40.3 g 
B) 0.0112 g 
C) 0.671 g 
D) 0.373 g 
E) 10.06 g 
A) 40.3 g 
B) 0.0112 g 
C) 0.671 g 
D) 0.373 g 
E) 10.06 g

Question 3

Determine Keq at 25 °C for the following reaction:
Pb2+(aq)+ Cu(s)⇌ Cu2+(aq)+ Pb(s)
The half-reactions are:
Pb2+(aq)+ 2 e- ⇌ Pb(s)E° = -0.125 V
Cu2+(aq)+ 2 e- ⇌ Cu(s)E° = +0.337 V

Accepted Answer

A) 2 × 1069  
B) 3 × 10-16 
C) 2 × 1016  
D) 2 × 10-8  
E) 6 × 107  
A) 2 × 1069  
B) 3 × 10-16 
C) 2 × 1016  
D) 2 × 10-8  
E) 6 × 107

Question 4

For the cell reaction at 25 °C Cu2+(aq)+ Zn(s)→ Cu(s)+ Zn2+(aq),E°cell = +1.100 V.What is the equilibrium constant for this reaction?

Accepted Answer

A) 3 × 10-19  
B) 2 × 1037  
C) 2 × 10-37  
D) 3 × 1018  
E) 3 × 10-18  
A) 3 × 10-19  
B) 2 × 1037  
C) 2 × 10-37  
D) 3 × 1018  
E) 3 × 10-18

Question 5

For the reaction: Mg(s)+ AgNO3(aq)→ Ag(s)+ Mg(NO3)2(aq)
Ag+(aq)+ e- → Ag(s)E° = 0.800 V
Mg2+(aq)+ 2 e- → Mg(s)E° = -2.356 V
Is the reaction spontaneous and why?

Accepted Answer

A) No,Mg(s)does not react with Ag+. 
B) No,E° is a positive value. 
C) No,E° is a negative value. 
D) Yes,E° is a positive value. 
E) Yes,E° is a negative value. 
A) No,Mg(s)does not react with Ag+. 
B) No,E° is a positive value. 
C) No,E° is a negative value. 
D) Yes,E° is a positive value. 
E) Yes,E° is a negative value.

Question 6

The lithium-ion battery is based on:

Accepted Answer

A) Li+(aq)/Li(s)couple 
B) Co3+(aq)/Co2+(aq)couple 
C) Co(III)/Co(IV)couple 
D) both Li+(aq)/Li(s)and Co3+(aq)/Co2+(aq) 
E) both Li+(aq)/Li(s)and Co(III)/Co(IV) 
A) Li+(aq)/Li(s)couple 
B) Co3+(aq)/Co2+(aq)couple 
C) Co(III)/Co(IV)couple 
D) both Li+(aq)/Li(s)and Co3+(aq)/Co2+(aq) 
E) both Li+(aq)/Li(s)and Co(III)/Co(IV)

Question 7

In the cell Pt(s)∣ Fe2+(aq)∣ Fe3+(aq)   Cu2+(aq)∣ Cu(s)which will increase the cell voltage the most?

Accepted Answer

A) Halve [Cu2+]. 
B) Halve [Fe2+]. 
C) Double [Cu2+]. 
D) Double [Fe2+]. 
E) Cut Cu electrode in half. 
A) Halve [Cu2+]. 
B) Halve [Fe2+]. 
C) Double [Cu2+]. 
D) Double [Fe2+]. 
E) Cut Cu electrode in half.

Question 8

What is the Ecell for the following cell at 25 °C?
Pt(s)∣ Sn2+ (aq,0.233 M),Sn4+ (aq,1.05 M)   Ag+ (aq,2.22 × 10-2 M)∣ Ag(s)
Ag+(aq)+ e- → Ag(s)E° = 0.800 V
Sn4+(aq)+ 2 e- → Sn2+(aq)E° = 0.154 V

Accepted Answer

A) 0.763 V 
B) 0.529 V 
C) 0.412 V 
D) 0.680 V 
E) 0.578 V 
A) 0.763 V 
B) 0.529 V 
C) 0.412 V 
D) 0.680 V 
E) 0.578 V

Question 9

The electrolysis of molten   (aq)for 3.25 hr with an electrical current of 15.0 A produces  
Of aluminum metal.

Accepted Answer

A) 147 
B) 0.606 
C) 4.55 ×   
D) 16.4 
E) 49.1 
A) 147 
B) 0.606 
C) 4.55 ×   
D) 16.4 
E) 49.1

Question 10

The standard cell potential (E°)of a voltaic cell constructed using the cell reaction below is 0.76 V:
Zn(s)+   (aq)→   (aq)+   (g)
With   = 1.0 atm and [   ] = 1.0 mol L-1,the cell potential is 0.66 V.The concentration of   (aq)in the cathode compartment is ________ mol L-1.

Accepted Answer

A) 2.0 × 10-2 
B) 4.2 × 10-4 
C) 1.4 × 10-1 
D) 4.9 × 101 
E) 1.0 × 10-12 
A) 2.0 × 10-2 
B) 4.2 × 10-4 
C) 1.4 × 10-1 
D) 4.9 × 101 
E) 1.0 × 10-12

Question 11

The active metal is called a sacrificial cathode.

Accepted Answer

A) True 
 B)False

Question 12

A solution of AgNO3(aq)is electrolyzed by passing 144 A of current for 102 min.What mass of silver plates out?

Accepted Answer

A) 16.4 g 
B) 5.91 × 104 g 
C) 985 g 
D) 9.13 g 
E) 6.84 g 
A) 16.4 g 
B) 5.91 × 104 g 
C) 985 g 
D) 9.13 g 
E) 6.84 g

Question 13

In a zinc-lead cell the reaction is:
Pb2+(aq)+ Zn(s)→ Pb(s)+ Zn2+(aq)E° = 0.637 V
Which of the following statements about this cell is FALSE?

Accepted Answer

A) The zinc electrode is the cathode. 
B) The reaction will go in the direction indicated. 
C) The shorthand notation is Zn(s)∣ Zn2+(aq)   Pb2+(aq)∣ Pb(s). 
D) The actual cell voltage is less than +0.637 volts because of concentration polarization and possible other factors. 
E) The lead electrode is positively charged. 
A) The zinc electrode is the cathode. 
B) The reaction will go in the direction indicated. 
C) The shorthand notation is Zn(s)∣ Zn2+(aq)   Pb2+(aq)∣ Pb(s). 
D) The actual cell voltage is less than +0.637 volts because of concentration polarization and possible other factors. 
E) The lead electrode is positively charged.

Question 14

Will magnesium metal displace Al3+(aq)ion from an aqueous solution?
Mg2+(aq)+ 2 e- → Mg(s)E° = -2.356 V
Al3+(aq)+ 3 e- → Al(s)E° = -1.676 V

Accepted Answer

A) No,since E°cell is negative. 
B) Yes,since E°cell is negative. 
C) No,the reverse reaction is spontaneous. 
D) Yes,since E°cell is positive. 
E) No,the system is at equilibrium. 
A) No,since E°cell is negative. 
B) Yes,since E°cell is negative. 
C) No,the reverse reaction is spontaneous. 
D) Yes,since E°cell is positive. 
E) No,the system is at equilibrium.

Question 15

What is Ecell at 25 °C of the spontaneous cell made from Ag+(aq)/Ag(s)(0.80 V)and Cl2(g)/Cl-(aq)(1.36 V)half cells if [Ag+] = 1 × 10-2 M and [Cl-] = 1 × 10-4 M with P(Cl2)= 1.1 atm?

Accepted Answer

A) 0.65 V 
B) 0.38 V 
C) 0.74 V 
D) 0.92 V 
E) 0.20 V 
A) 0.65 V 
B) 0.38 V 
C) 0.74 V 
D) 0.92 V 
E) 0.20 V

Question 16

Calculate the mass of I2(s)produced at the anode if a current of 2.85 A is passed through a solution of KI(aq)for 56 minutes.

Accepted Answer

A) 0.42 g 
B) 0.13 g 
C) 13 g 
D) 25 g 
E) 4.3 g 
A) 0.42 g 
B) 0.13 g 
C) 13 g 
D) 25 g 
E) 4.3 g

Question 17

The following half-reactions are used in the zinc-air battery.
   (aq)+ 2 e- → Zn(s)+ 4 OH-(aq)E° = -1.199 V
O2(g)+ 2 H2O(l)+ 4 e- → 4 OH-(aq)E° = +0.401 V
How much charge is transferred per gram Zn(s)in this voltaic cell?

Accepted Answer

A) 5.90 × 103 C 
B) 2.95 × 103 C 
C) 1.47 × 103 C 
D) 3.39 × 10-4 C 
E) 1.69 × 10-4 C 
A) 5.90 × 103 C 
B) 2.95 × 103 C 
C) 1.47 × 103 C 
D) 3.39 × 10-4 C 
E) 1.69 × 10-4 C

Question 18

The gas OF2 can be produced from the electrolysis of an aqueous solution of KF,as shown in the equation below:
OF2(g)+ 2 H+(aq)+ 4 e- → H2O(l)+ 2 F-(aq)E° = +2.15 V
Using the given standard reduction potential,calculate the amount of OF2 that is produced,and the electrode at which the OF2 is produced,upon the passage of 0.480 faradays through an aqueous KF solution.

Accepted Answer

A) 6.48 g of OF2 at the anode 
B) 26.0 g of OF2 at the anode 
C) 6.48 g of OF2 at the cathode 
D) 26.0 g of OF2 at the cathode 
A) 6.48 g of OF2 at the anode 
B) 26.0 g of OF2 at the anode 
C) 6.48 g of OF2 at the cathode 
D) 26.0 g of OF2 at the cathode

Question 19

Choose the INCORRECT statement.

Accepted Answer

A) Electrons are transferred in oxidation-reduction reactions. 
B) A strip of metal in a solution of ions of that metal is an electrode potential. 
C) Reduction is the gain of electrons. 
D) Oxidation is the loss if electrons. 
E) A salt bridge maintains electrical contact between two half cells. 
A) Electrons are transferred in oxidation-reduction reactions. 
B) A strip of metal in a solution of ions of that metal is an electrode potential. 
C) Reduction is the gain of electrons. 
D) Oxidation is the loss if electrons. 
E) A salt bridge maintains electrical contact between two half cells.

Question 20

Write the net redox reaction that occurs in the following galvanic cell.
Ti(s)∣ Ti3+(aq)   Se(s)| Se2-(aq)

Accepted Answer

A) Ti(s)+ Se2-(aq)+ 1 e- → Ti3+(aq)+ Se(s) 
B) 2 Ti(s)+ 3 Se(s)→ 2 Ti3+(aq)+ 3 Se2-(aq) 
C) Ti(s)+ Se(s)→ Ti3+(aq)+ Se2-(aq)+ 1 e-  
D) 2 Ti3+(aq)+ 3 Se(s)→ 2 Ti(s)+ 3 Se2-(aq) 
E) 2 Ti3+(aq)+ 3 Se(s)+ 1 e- → 2 Ti(s)+ 3 Se2-(aq) 
A) Ti(s)+ Se2-(aq)+ 1 e- → Ti3+(aq)+ Se(s) 
B) 2 Ti(s)+ 3 Se(s)→ 2 Ti3+(aq)+ 3 Se2-(aq) 
C) Ti(s)+ Se(s)→ Ti3+(aq)+ Se2-(aq)+ 1 e-  
D) 2 Ti3+(aq)+ 3 Se(s)→ 2 Ti(s)+ 3 Se2-(aq) 
E) 2 Ti3+(aq)+ 3 Se(s)+ 1 e- → 2 Ti(s)+ 3 Se2-(aq)

Exam 19: Electrochemistry

Choose the INCORRECT statement.

What mass of silver can be deposited by the passage of a constant current of 5.00 A through a AgNO3(aq)solution for 2.00 hours?

Determine Keq at 25 °C for the following reaction: Pb2+(aq)+ Cu(s)⇌ Cu2+(aq)+ Pb(s) The half-reactions are: Pb2+(aq)+ 2 e- ⇌ Pb(s)E° = -0.125 V Cu2+(aq)+ 2 e- ⇌ Cu(s)E° = +0.337 V

For the cell reaction at 25 °C Cu2+(aq)+ Zn(s)→ Cu(s)+ Zn2+(aq),E°cell = +1.100 V.What is the equilibrium constant for this reaction?

For the reaction: Mg(s)+ AgNO3(aq)→ Ag(s)+ Mg(NO3)2(aq) Ag+(aq)+ e- → Ag(s)E° = 0.800 V Mg2+(aq)+ 2 e- → Mg(s)E° = -2.356 V Is the reaction spontaneous and why?

The lithium-ion battery is based on:

In the cell Pt(s)∣ Fe2+(aq)∣ Fe3+(aq) Cu2+(aq)∣ Cu(s)which will increase the cell voltage the most?

What is the Ecell for the following cell at 25 °C? Pt(s)∣ Sn2+ (aq,0.233 M),Sn4+ (aq,1.05 M) Ag+ (aq,2.22 × 10-2 M)∣ Ag(s) Ag+(aq)+ e- → Ag(s)E° = 0.800 V Sn4+(aq)+ 2 e- → Sn2+(aq)E° = 0.154 V

The electrolysis of molten (aq)for 3.25 hr with an electrical current of 15.0 A produces Of aluminum metal.

The standard cell potential (E°)of a voltaic cell constructed using the cell reaction below is 0.76 V: Zn(s)+ (aq)→ (aq)+ (g) With = 1.0 atm and [ ] = 1.0 mol L-1,the cell potential is 0.66 V.The concentration of (aq)in the cathode compartment is ________ mol L-1.

The active metal is called a sacrificial cathode.

A solution of AgNO3(aq)is electrolyzed by passing 144 A of current for 102 min.What mass of silver plates out?

In a zinc-lead cell the reaction is: Pb2+(aq)+ Zn(s)→ Pb(s)+ Zn2+(aq)E° = 0.637 V Which of the following statements about this cell is FALSE?

Will magnesium metal displace Al3+(aq)ion from an aqueous solution? Mg2+(aq)+ 2 e- → Mg(s)E° = -2.356 V Al3+(aq)+ 3 e- → Al(s)E° = -1.676 V

What is Ecell at 25 °C of the spontaneous cell made from Ag+(aq)/Ag(s)(0.80 V)and Cl2(g)/Cl-(aq)(1.36 V)half cells if [Ag+] = 1 × 10-2 M and [Cl-] = 1 × 10-4 M with P(Cl2)= 1.1 atm?

Calculate the mass of I2(s)produced at the anode if a current of 2.85 A is passed through a solution of KI(aq)for 56 minutes.

The following half-reactions are used in the zinc-air battery. (aq)+ 2 e- → Zn(s)+ 4 OH-(aq)E° = -1.199 V O2(g)+ 2 H2O(l)+ 4 e- → 4 OH-(aq)E° = +0.401 V How much charge is transferred per gram Zn(s)in this voltaic cell?

Choose the INCORRECT statement.

Write the net redox reaction that occurs in the following galvanic cell. Ti(s)∣ Ti3+(aq) Se(s)| Se2-(aq)

Matter: Its Properties and Measurement

Atoms and the Atomic Theory

Chemical Compounds

Chemical Reactions

Introduction to Reactions in Aqueous Solutions

Gases

Thermochemistry

Electrons in Atoms

The Periodic Table and Some Atomic Properties

Chemical Bonding I: Basic Concepts

Chemical Bonding Ii: Valence Bond and Molecular Orbital Theories

Intermolecular Forces: Liquids and Solids

Spontaneous Change: Entropy and Gibbs Energy

Solutions and Their Physical Properties

Principles of Chemical Equilibrium

Acids and Bases

Additional Aspects of Acidbase Equilibria

Solubility and Complex-Ion Equilibria

Chemical Kinetics

Chemistry of the Main-Group Elements I: Groups 1,2,13,and 14

Chemistry of the Main-Group Elements Ii: Groups 18,17,16,15,and Hydrogen

The Transition Elements

Complex Ions and Coordination Compounds

Nuclear Chemistry

Structures of Organic Compounds

Reactions of Organic Compounds

Chemistry of the Living State

Filters

What mass of silver can be deposited by the passage of a constant current of 5.00 A through a AgNO₃(aq)solution for 2.00 hours?

Determine K_eq at 25 °C for the following reaction: Pb²⁺(aq)+ Cu(s)⇌ Cu²⁺(aq)+ Pb(s) The half-reactions are: Pb²⁺(aq)+ 2 e^- ⇌ Pb(s)E° = -0.125 V Cu²⁺(aq)+ 2 e^- ⇌ Cu(s)E° = +0.337 V

For the cell reaction at 25 °C Cu²⁺(aq)+ Zn(s)→ Cu(s)+ Zn²⁺(aq),E°_cell = +1.100 V.What is the equilibrium constant for this reaction?

For the reaction: Mg(s)+ AgNO₃(aq)→ Ag(s)+ Mg(NO₃)₂(aq) Ag⁺(aq)+ e^- → Ag(s)E° = 0.800 V Mg²⁺(aq)+ 2 e^- → Mg(s)E° = -2.356 V Is the reaction spontaneous and why?

In the cell Pt(s)∣ Fe²⁺(aq)∣ Fe³⁺(aq) Cu²⁺(aq)∣ Cu(s)which will increase the cell voltage the most?

What is the E_cell for the following cell at 25 °C? Pt(s)∣ Sn²⁺ (aq,0.233 M),Sn⁴⁺ (aq,1.05 M) Ag⁺ (aq,2.22 × 10^-2 M)∣ Ag(s) Ag⁺(aq)+ e^- → Ag(s)E° = 0.800 V Sn⁴⁺(aq)+ 2 e^- → Sn²⁺(aq)E° = 0.154 V

The standard cell potential (E°)of a voltaic cell constructed using the cell reaction below is 0.76 V: Zn(s)+ (aq)→ (aq)+ (g) With = 1.0 atm and [ ] = 1.0 mol L^-1,the cell potential is 0.66 V.The concentration of (aq)in the cathode compartment is ________ mol L^-1.

A solution of AgNO₃(aq)is electrolyzed by passing 144 A of current for 102 min.What mass of silver plates out?

In a zinc-lead cell the reaction is: Pb²⁺(aq)+ Zn(s)→ Pb(s)+ Zn²⁺(aq)E° = 0.637 V Which of the following statements about this cell is FALSE?

Will magnesium metal displace Al³⁺(aq)ion from an aqueous solution? Mg²⁺(aq)+ 2 e^- → Mg(s)E° = -2.356 V Al³⁺(aq)+ 3 e^- → Al(s)E° = -1.676 V

What is E_cell at 25 °C of the spontaneous cell made from Ag⁺(aq)/Ag(s)(0.80 V)and Cl₂(g)/Cl^-(aq)(1.36 V)half cells if [Ag⁺] = 1 × 10^-2 M and [Cl^-] = 1 × 10^-4 M with _P(Cl₂)= 1.1 atm?

Calculate the mass of I₂(s)produced at the anode if a current of 2.85 A is passed through a solution of KI(aq)for 56 minutes.

The following half-reactions are used in the zinc-air battery. (aq)+ 2 e^- → Zn(s)+ 4 OH^-(aq)E° = -1.199 V O₂(g)+ 2 H₂O(l)+ 4 e^- → 4 OH^-(aq)E° = +0.401 V How much charge is transferred per gram Zn(s)in this voltaic cell?

Write the net redox reaction that occurs in the following galvanic cell. Ti(s)∣ Ti³⁺(aq) Se(s)| Se^2-(aq)