Deck 19: Electrochemistry

Question 1

Choose the INCORRECT statement.

A)An electrode is often a strip of metal.
B)An electrode in a solution of its ions is a half cell.
C)An electrochemical cell is a half cell.
D)The electromotive force (emf)is the cell potential.
E)The cell potential is the potential difference between the half cells.

Answer 1

An electrochemical cell is a half cell.

Question 2

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?

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.

Answer 2

The zinc electrode is the cathode.

Question 3

The active metal is called a sacrificial cathode.

Answer 3

False

Question 4

Choose the INCORRECT statement.

A)SHE stands for Standard Helium Electrodes.
B)E° is the standard electrode potential.
C)The standard electrode potential is the reduction potential of a half cell.
D)The standard cell potential is the potential difference between two half cells.
E)E°_cell is the standard cell potential.

Question 5

Choose the correct statement based on the following oxidation potentials.
Mg/Mg²⁺ +2.37 v Fe/Fe²⁺ +0.44 v Cu/Cu²⁺ -0.34 v
Zn/Zn²⁺ +0.76 v Sn/Sn²⁺ +0.14 v Ag/Ag⁺ -0.80 v

A)Mg will not displace Zn²⁺ from solution
B)Cu will displace Sn²⁺ from solution
C)Fe will displace Zn²⁺ from solution
D)Fe will displace H⁺ from solution
E)Sn will displace Fe²⁺ from solution

Question 6

Choose the INCORRECT statement.

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 7

In a galvanic cell,oxidation occurs at the cathode.

Question 8

In a galvanic cell,oxidation occurs at the:

A)anode
B)cathode
C)salt bridge
D)electrolyte
E)in cathodic space

Question 9

Corrosion of metals is an oxidation-reduction process.

Question 10

Choose the INCORRECT statement.

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 11

Choose the INCORRECT statement.

A)A double vertical line separates half cells in a cell diagram.
B)A single vertical line separates phases in a cell diagram.
C)A voltaic cell is a galvanic cell.
D)Voltaic cells produce an electron flow.
E)Electrolytic cells are cells where electron flow is caused by spontaneous reactions.

Question 12

The E_cell for the following concentration cell at 25 °C is 0.006 V.
Pt ∣ H₂ (g,0.025 atm)∣ H⁺ (0.012 M)
H⁺ (1 M)∣ H₂ (g,1 atm)∣ Pt
2 H⁺(aq)+ 2 e^- → H₂(g)E° = 0.V

Question 13

Cathodic protection is attaching a more active metal to the protected metal.

Question 14

A primary battery is recharged by passing electricity through the battery.

Question 15

E°_cell is the standard cell potential.

Question 16

In the electrolysis of water,oxygen is evolved at the cathode.

Question 17

When E_cell < 0,the reaction is spontaneous.

Question 18

Choose the INCORRECT statement.

A)When a half reaction is reversed,the sign of the potential is changed.
B)Reversing a half reaction makes it a reduction potential.
C)Each electrochemical cell consists of a reduction half cell and an oxidation half cell.
D)A voltaic cell is also called a battery.
E)The potential difference of a cell is the voltage of the cell.

Question 19

The hydrogen standard electrode is the most convenient standard electrode to use.

Question 20

Primary batteries' cell reactions cannot be reversed.

Question 21

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
Estimate K_eq at 25 °C.

A)5.7 × 10¹⁰⁶
B)2.0 × 10⁵³
C)3.7 × 10⁵²
D)1.1 × 10²⁷
E)10^-107

Question 22

Which of the following are commonly used as alternate standard electrodes:
I.Ag(s)| AgCl(s)| Cl^- ((aq,1.0 M)
II.Hg(l)| HgCl₂(s)| Cl^- (aq,1.0 M)
III.Ag(s)| AgCl(s)| Cl^- ((aq,1.0 M)
IV.Hg(l)| Hg₂Cl₂(s)| Cl^- (aq,1.0 M)
V.Hg(s)| Hg₂Cl₂(s)| Cl^- (aq,1.0 M)

A)I and V
B)II and IV
C)I and IV
D)II and III
E)I and III

Question 23

Determine the K_sp at 25 °C of AgCl(s).The half-reactions are:
Ag⁺(aq)+ 1 e^- → Ag(s)E° = +0.771 V
AgCl(s)+ 1 e^- → Ag(s)+ Cl^-(aq) E° = +0.222 V

A)1 × 10^-2
B)0.771
C)4 × 10¹¹
D)5 × 10^-10
E)4 × 10^-11

Question 24

Choose the INCORRECT statement.

A)The work available in a cell = -zFE_cell.
B)ΔG ° = -zFE°_cell
C)When E_cell < 0,the reaction is spontaneous.
D)When E_cell = 0,the reaction is at equilibrium.
E)Reversing a cell reaction changes the sign of E_cell.

Question 25

What is the concentration of Cu²⁺(aq)in the following cell at 25 °C if the cell voltage is 1.253 V?
Zn(s)∣ Zn²⁺ (aq,0.125 M) Cu²⁺(?)∣ Cu(s)
Cu²⁺(aq)+ 2 e^- → Cu(s)E° = 0.340 V
Zn²⁺(aq)+ 2 e^- → Zn(s)E° = -0.763 V

A)0.6 M
B)1 × 10^-2 M
C)1 × 10^-6 M
D)9 × 10^-4 M
E)4 × 10^-4 M

Question 26

If the voltage of an electrochemical cell is negative then the cell reaction is:

A)nonspontaneous
B)slow
C)exothermic
D)spontaneous
E)fast

Question 27

Determine E°_cell for the reaction: 2 Al(aq)+ 3 Zn²⁺(aq)→ 2 Al³⁺(aq)+ 3 Zn(s).The half reactions are:
Al³⁺(aq)+ 3 e^- → Al(s)E° = -1.676 V
Zn²+(aq)+ 2 e^- → Zn(s)E° = -0.763 V

A)0.913 V
B)-2.439 V
C)2.439 V
D)-1.063 V
E)-0.913 V

Question 28

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?

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 29

Glass electrodes are used for direct measurement of:

A)pH
B)pK_a
C)K_sp
D)Q
E)pK_w

Question 30

The lithium-ion battery is based on:

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 31

Choose the INCORRECT statement.

A)One mole of hydrogen ions will have a positive charge of one Faraday.
B)One Faraday of charge will release 35.5 g of Cl₂(g)in the electrolysis of a chloride solution.
C)One Faraday of charge will plate out two moles of Cu(s)from a solution of CuSO₄(aq).
D)One mole of electrons has a charge of l Faraday.
E)One mole of hydrogen gas requires 2 Faradays.

Question 32

Choose the INCORRECT statement.

A)A concentration cell consists of half cells with identical electrodes but different ion concentrations.
B)Primary batteries' cell reactions cannot be reversed.
C)Secondary batteries' cell reaction can be reversed.
D)A primary battery is recharged by passing electricity through the battery.
E)Cells can be joined in series to increase the total voltage.

Question 33

Consider the cell:
Ni(s)∣ Ni²⁺ (aq,?M) Cu²⁺ (aq,0.136 M)∣ Cu(s)
Ni²⁺(aq)/Ni(s) E° = -0.257 V Cu²⁺(aq)/Cu(s) E° = 0.340 V
The measured potential of the cell is 0.621 V.What is [Ni^2+] at 25 °C?

A)2 × 10^-2 M
B)1 M
C)4 × 10^-42 M
D)0.05 M
E)0.4 M

Question 34

Choose the INCORRECT statement.

A)Corrosion of metals is an oxidation reduction process.
B)Rust is a form of corrosion.
C)Metals can be protected by cathodic protection.
D)Cathodic protection is attaching a more active metal to the protected metal.
E)The active metal is called a sacrificial cathode.

Question 35

What is the cell diagram for the spontaneous cell involving the Fe³⁺(aq)∣ Fe²⁺(aq)∣ Pt(s)(0.771V)half cell and the Zn²⁺(aq)∣ Zn(s)(-0.763 V)half cell?

A)Fe²⁺(aq)∣ Fe³⁺(aq) Zn²⁺(aq)∣ Zn(s)
B)Pt(s)∣ Fe²⁺(aq),Fe³⁺(aq) Zn²⁺(aq)∣ Zn(s)
C)Zn(s)∣ Zn²⁺(aq) Fe³⁺(aq)∣ Fe²⁺(aq)∣ Pt(s)
D)Zn(s)∣ Zn²⁺(aq) Fe³⁺(aq)∣ Fe²⁺(aq)
E)Zn(s)∣ Zn²⁺(aq) Fe³⁺(aq)∣ Fe²⁺(aq)∣ Zn(s)

Question 36

Determine E°_cell for the reaction: 2 Ag⁺(aq)+ Mg(s)→ 2 Ag(s)+ Mg²⁺(aq).The half reactions are:
Mg²⁺(aq)+ 2 e^- → Mg(s)E° = -2.356 V
Ag⁺(aq)+ e^- → Ag(s)E° = 0.800 V

A)0.756 V
B)-0.756 V
C)3.156 V
D)-1.556 V
E)1.556 V

Question 37

What is the concentration of Al³⁺(aq)in the following cell at 25 °C if the cell voltage is 1.486 V?
Al(s)∣ Al³⁺(aq,?) Sn²⁺(aq,3.21 × 10^-4 M)∣ Sn(s)
Al³⁺(aq)+ 3 e^- → Al(s)E° = -1.676 V
Sn²⁺(aq)+ 2 e^- → Sn(s)E° = -0.137 V

A)2.8 × 10^-3 M
B)1.6 × 10^-5 M
C)4.5 × 10^-5 M
D)2.4 × 10^-2 M
E)7.8 × 10^-6 M

Question 38

Calculate the K_sp of lead iodide from the following standard electrode potentials,at 25 °C:
2 e^- + PbI₂(S)→ Pb(s)+ 2 I^-(aq)E° = -0.365 V
2 e^- + Pb²⁺(aq)→ Pb(s)E° = -0.126 V

A)8 × 10^-9
B)9 × 10^-5
C)2 × 10^-17
D)5 × 10^-13
E)6 × 10^-5

Question 39

Determine E°_cell for the reaction: Pb²⁺(aq)+ Zn(s)→ Pb(s)+ Zn²⁺(aq).The half reactions are:
Pb²⁺(aq)+ 2 e^- → Pb(s)E° = -0.125 V
Zn²+(aq)+ 2 e^- → Zn(s)E° = -0.763 V

A)0.638 V
B)-0.638 V
C)0.888 V
D)-1.276 V
E)-0.888 V

Question 40

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

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

Question 41

Choose the INCORRECT completion of the following sentence:
"In the electrolysis of water...

A)...a direct current must be used."
B)...oxygen is evolved at the cathode."
C)...electrical energy must be supplied continuously because it is an endothermic reaction."
D)...the volume of hydrogen produced is twice the volume of oxygen produced."
E)....one mole of H₂(g)is produced for each two moles of electrons."

Question 42

An electrolysis is carried out by passing an electric current through a solution of copper sulfate using inert electrodes.This causes:

A)Cu(s)to plate out on the negative electrode
B)Cu(s)to plate out on the anode
C)oxygen to form on the negative electrode
D)H₂(g)to form at the negative electrode
E)sulfur to form on the positive electrode

Question 43

Determine E°_cell 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

A)0.212 V
B)-0.462 V
C)0.462 V
D)-0.212 V
E)0.424 V

Question 44

Determine E°_cell for the reaction: 2 Ag(s)+ Mg²⁺(aq)→ 2 Ag⁺(aq)+ Mg.(s)The half reactions are:
Mg²⁺(aq)+ 2 e^- → Mg(s)E° = -2.356 V
Ag⁺(aq)+ e^- → Ag(s)E° = 0.800 V

A)0.756 V
B)-0.756 V
C)3.156 V
D)-3.156 V
E)1.556 V

Question 45

Determine E°_cell for the reaction: Pb(s)+ Cu²⁺(aq)→ Pb²⁺(aq)+ Cu(s).The half reactions are:
Pb²⁺(aq)+ 2 e^- → Pb(s)E° = -0.125 V
Cu²⁺(aq)+ 2 e^- → Cu(s)E° = 0.340 V

A)0.215 V
B)0.465 V
C)0.930 V
D)-0.215 V
E)-0.465 V

Question 46

Determine E°_cell for the reaction: Cl₂(g)+ 2 F^-(aq)→ 2 Cl^-(aq)+ F₂(g).The half reactions are:
F₂(g)+ 2 e^- → 2 F^-(aq)E° = +2.866 V
Cl₂(g)+ 2 e^- → 2 Cl^-(aq)E° = 1.358 V

A)3.016 V
B)-4.224 V
C)1.508 V
D)4.224 V
E)-1.508 V

Question 47

Determine E°_cell for the reaction:
Pb(s)+ Zn²⁺(aq)→ Pb²⁺(aq)+ Zn(s).
The half reactions are:
Pb²⁺(aq)+ 2 e^- → Pb(s)E° = -0.125 V
Zn²+(aq)+ 2 e^- → Zn(s)E° = -0.763 V

A)0.638 V
B)-0.638 V
C)0.888 V
D)-1.276 V
E)-0.888 V

Question 48

Determine E°_cell for the reaction: I₂(s)+ Cu(s)→ 2 I^-(aq)+ Cu²⁺(aq).The half reactions are:
I₂(s)+ 2 e^- → 2 I^-(aq)E° = +0.535 V
Cu²⁺(aq)+ 2 e^- → Cu(s)E° = 0.340 V

A)0.730 V
B)-0.875 V
C)0.875 V
D)0.195 V
E)-0.195 V

Question 49

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

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

Question 50

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?

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 51

For the reaction: Mg(s)+ 2 AgNO₃(aq)→ 2 Ag(s)+ Mg(NO₃)₂(aq)
Write a voltaic diagram for the reaction.

A)Ag(s)| Ag(aq) Mg²⁺(aq)| Mg(s)
B)Mg(s)∣ Mg²⁺ Ag⁺ (aq)∣ Ag (s)
C)Mg(s)∣ Mg²⁺ Ag(s)∣ Ag⁺ (aq)
D)Ag(aq)∣ Ag(s) Mg(s)∣ Mg2⁺ (aq)
E)Ag(s)∣ Mg²⁺ (aq) Ag⁺ (aq)∣ Mg(s)

Question 52

Write the net redox reaction that occurs in the galvanic cell.
Zn(s)∣ Zn⁺²(aq) Pb⁺²(aq)∣ Pb(s)

A)Pb(s)+ Zn(s)→ Pb⁺²(aq)+ Zn⁺²(aq)+ 4 e^-
B)Pb(s)+ Zn⁺²(aq)→ Pb⁺²(aq)+ Zn(s)
C)Pb⁺²(s)+ Zn⁺²(s)→ Pb(s)+ Zn(s)+ 4 e^-
D)Pb⁺²(aq)+ Zn(s)→ Zn⁺²(aq)+ Pb(s)
E)Pb(s)+ Zn(s)+ 4 e^- → Pb⁺²(aq)+ Zn⁺²(aq)

Question 53

How many coulombs would be needed to deposit all of the Ag⁺(aq)ion from 600 mL of a solution 0.250 M in Ag⁺(aq)?

A)1.45 × 10⁷ C
B)1.56 × 10⁶ C
C)1.45 × 10⁴ C
D)2.41 × 10⁴ C
E)1.56 × 10⁴ C

Question 54

Determine E°_cell for the reaction: 2 Al³⁺(aq)+ 3 Zn(s)→ 2 Al + 3 Zn²⁺(aq).The half reactions are:
Al³⁺(aq)+ 3 e^- → Al(s)E° = -1.676 V
Zn²+(aq)+ 2 e^- → Zn(s)E° = -0.763 V

A)0.913 V
B)-2.439 V
C)2.439 V
D)-1.063 V
E)-0.913 V

Question 55

One mole of electrons has a charge of:

A)96,485 A
B)1.60 × 10^-19
C)6.02 × 10²³ A
D)96,485 C
E)96,485 F

Question 56

Determine E°_cell for the reaction: MnO₄^-(aq)+ 8 H⁺(aq)+ 5 Fe²⁺(aq)→ Mn²⁺(aq)+ 4 H₂O(l)+ 5 Fe³⁺(aq).The half reactions are:
Fe³⁺(aq)+ e^- → Fe²⁺(aq)E° = +0.771 V
MnO₄^-(aq)+ 8 H⁺(aq)+ 5 e^- → Mn²⁺(aq)+ 4 H₂O(l)E° = 1.507 V

A)-2.34 V
B)-2.28 V
C)2.28 V
D)-0.74 V
E)0.74 V

Question 57

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
For the reaction,determine E° for the cell.

A)1.556 V
B)-3.156 V
C)3.156 V
D)0.800 V
E)2.356 V

Question 58

Given the table below predict the numerical value of the standard cell potential for the reaction:
2 Cr(s)+ 3 Cu²⁺(aq)→ 2 Cr³⁺(aq)+ 3 Cu(s)
Half Reaction E° (volts)
(1)Cr³⁺(aq)+ 3 e^- → Cr(s)-0.74
(2)Cr³⁺(aq)+ e^- → Cr²⁺(aq)-0.41
(3)Cr₂O₇^2-(aq)+ 14 H⁺(aq)+ 6 e^- → 2 Cr³⁺(aq)+ 7 H₂O(l)1.33
(4)Cu⁺(aq)+ e^- → Cu(s)0.52
(5)Cu²⁺(aq)+ 2 e^- → Cu(s)0.34
(6)Cu²⁺(aq)+ e^- → Cu⁺(aq)0.16

A)2.50 volts
B)0.417 volts
C)-1.08 volts
D)1.08 volts
E)-0.40 volts

Question 59

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

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 60

Determine E°_cell at 25 °C for the following reaction:
3 Sn²⁺(aq)+ 2 Al(s)→ 2 Al³⁺(aq)+ 3 Sn(s)
Al³⁺(aq)+ 3 e^- → Al(s)E° = -1.676 V
Sn²⁺(aq)+ 2 e^- → Sn(s)E° = -0.137 V

A)2.941 V
B)-1.813 V
C)1.813 V
D)-1.539 V
E)1.539 V

Question 61

What is E° of the spontaneous cell made from the Zn²⁺(aq)^/Zn(s)(-0.76 V)and Br₂(l)_/2 Br^-(aq)(1.07 V)half cells?

A)-1.83 V
B)0.31 V
C)1.83 V
D)-0.31 V
E)-0.76 V

Question 62

What is the cell reaction of the spontaneous cell made from the Zn²⁺(aq)^/Zn(s)(-0.76 V)and Br₂(l)/2 Br^-(aq)(1.07 V)half cells?

A)2Br^-(aq)+ Zn²⁺(aq)→ Zn + Br₂(l)
B)Br₂(l)+ Zn → Zn²⁺(aq)+ 2Br^-(aq)
C)2Br^-(aq)+ Zn → Br₂(l)+ Zn²⁺(aq)
D)Br₂(l)+ Zn → Zn²⁺(aq)+ Br^-(aq)
E)Br₂(l)+ Zn²⁺(aq)→ Zn + 2Br^-(aq)

Question 63

The following galvanic cell has a measured cell potential E°_cell = 0.646 V.
Pt(s)∣ Sn⁴⁺(aq),Sn²⁺(aq) Ag⁺(aq)∣ Ag(s)
Given that the standard reduction potential for the reduction of Ag⁺(aq)to Ag(s)is +0.800 V,what is the standard reduction potential for the Sn⁴⁺/Sn²⁺ half-reaction?

A)+0.154 V
B)-0.154 V
C)+1.45 V
D)-1.45 V
E)+0.308 V

Question 64

The standard Gibbs energy change for the following voltaic cell is ΔG° = -89.3 kJ at 25 °C.What is E°_cell?
Ag(s)

A)+0.463 V
B)-0.926 V
C)-0.463 V
D)+0.926 V
E)+0.231 V

Question 65

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?

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

Question 66

Calculate E_cell at 25 °C for the following voltaic cell.K_sp for NiCO₃(s)is 1.42 × 10^-7.
Ni(s)∣ Ni²⁺(aq)[sat'd NiCO₃(s)] Ni²⁺(aq)(0.010M)∣ Ni(s)
The half-reaction is: Ni²⁺(aq)+ 2 e^- → Ni(s)E° = -0.257 V

A)+0.257 V
B)-0.257 V
C)0.000 V
D)+0.0844 V
E)+0.0422 V

Question 67

Find E_cell at 25 °C for the following voltaic cell:
Cu(s)∣ Cu²⁺(aq)(0.10 M) Cu²⁺(aq)(0.85 M)∣ Cu(s)
The half-reaction is:
Cu²⁺(aq)+ 2 e^- → Cu(s)E° = +0.377 volts

A)+0.0209 V
B)+0.0550 V
C)+0.0275 V
D)-0.0209 V
E)+0.310 V

Question 68

The net reaction in a voltaic cell with E°_cell = +0.726 V is,
2 Fe³⁺(aq)+ 3 Zn(s)→ 2 Fe(s)+ 3 Zn²⁺(aq)
What is ΔG° for this reaction at 25 °C?

A)-210 kJ
B)-140 kJ
C)-700 kJ
D)-463 kJ
E)-420 kJ

Question 69

What is Keq at 25 °C of the spontaneous cell made from the Zn²⁺(aq)/Zn(s)(-0.76 V)and Br₂(l)/2Br^-(aq)(1.07 V)half cells?

A)3 × 10¹⁰
B)3 × 10^-11
C)8 × 10⁶¹
D)2 × 10³⁶
E)5 × 10²⁵

Question 70

Determine E_cell at 25 °C for the following reaction at 25 °C:
Al(s)∣ Al³⁺(0.435 M) Sn²⁺(2.12 × 10^-3 M)∣ Sn(s)
3 Sn²⁺(aq)+ 2 Al(s)→ 2 Al³⁺(aq)+ 3 Sn(s)
Al³⁺(aq)+ 3 e^- → Al(s)E° = -1.676 V
Sn²⁺(aq)+ 2 e^- → Sn(s)E° = -0.137 V

A)1.227 V
B)1.611 V
C)1.562 V
D)1.487 V
E)1.467 V

Question 71

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

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

Question 72

Find E_cell for the following voltaic cell at 25 °C:
Ti(s)∣ Ti²⁺(aq)(0.550M) Sn²⁺(aq)(0.005 M)∣ Sn(s)
The half-reactions are:
Ti²⁺(aq)+ 2 e^- ⇔ Ti(s)E° = -1.630 V
Sn²⁺(aq)+ 2 e^- ⇔ Sn(s)E° = -0.137 V

A)1.372 V
B)1.707 V
C)1.646 V
D)1.433 V
E)-1.646 V

Question 73

What is E° of the spontaneous cell made from Ag⁺(aq)/Ag(s)(0.80 V)and Cl₂(g)/Cl^-(aq)(1.36 V)half cells?

A)2.16 V
B)-2.16 V
C)-0.56 V
D)0.56 V
E)1.36 V

Question 74

Using the following reduction half-reactions and their respective standard reduction potentials at 25 °C,draw a diagram of a galvanic cell.
Cr₂O₇^2-(aq)+ 14 H⁺(aq)+ 6e^- → 2 Cr³⁺(aq)+ 7 H₂O(l)E° = +1.33 V
Zn²+(aq)+ 2 e^- → Zn(s)E° = -0.763 V

A)Zn²⁺(aq)∣ Zn(s),H⁺(aq) Cr₂O₇^2-(aq),Cr(s)∣ Cr³⁺(aq)
B)Zn(s)∣ Zn²⁺(aq) H⁺(aq),Cr³⁺(aq)∣ Cr(s)
C)Cr(s)∣ Cr³⁺(aq),H⁺(aq),Cr₂O₇^2-(aq) Zn(S)∣ Zn²⁺(aq)
D)Zn(s)∣ Zn²⁺(aq) Cr₂O₇^2-(aq),H⁺(aq),Cr³⁺(aq)∣ Pt(s)
E)Pt(s)∣ Cr³⁺(aq),Cr₂O₇^2-(aq),H+(aq) Zn²⁺(aq)∣ Zn(s)

Question 75

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
Determine ΔG°.

A)-300.3 kJ/mol
B)304.5 kJ/mol
C)609.0 kJ/mol
D)-304.5 kJ/mol
E)-609.0 kJ/mol

Question 76

What is ΔG° at 25 °C for the reaction (not balanced): C₃H₈(g)+ O₂(g)→ CO₂(g)+ H₂O(l)if the standard cell potential is 1.092 V?

A)-105 kJ
B)-211 kJ
C)105 kJ
D)-2107 kJ
E)211 kJ

Question 77

What is the cell diagram for the spontaneous cell involving the Cl₂(g)∣ Cl-(aq)(1.358 V)and the Sn²⁺(aq)∣ Sn(s)(-0.137V)half cells?

A)Pt(s)∣ Cl₂(g)∣ Cl^-(aq) Sn²⁺(aq)∣ Sn(s)
B)Sn(s)∣ Sn²⁺(aq) Cl^-(aq)∣ Cl₂(g)∣ Pt(s)
C)Cl₂(g)∣ Cl^-(aq) Sn²⁺(aq)∣ Sn(s)
D)Sn(s) Sn²⁺(aq) Cl^-(aq)∣ Cl₂(g)
E)Sn(s)∣ Cl^-(aq) Sn²⁺(aq)∣ Sn(s)

Question 78

What is K_eq 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?

A)9 × 10^-74
B)1 × 10^-19
C)1 × 10⁷³
D)9 × 10¹⁸
E)1 × 10²⁷

Question 79

What is the standard cell potential if the Gibbs energy is -2108 kJ in the reaction:
C₃H₈(g)+ O₂(g)→ CO₂(g)+ H₂O(l)(not balanced)?

A)-10.92 V
B)10.92 V
C)21.85 V
D)-1.092 V
E)1.092 V

Question 80

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?

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