Chapter 18 1 Balanced Redox Equation Must Have Which The

Chapter 18 – Electrochemistry

Chapter 18

Electrochemistry

1. A balanced redox equation must have which of the following:

I. The same number of each type of atom on both sides of the equation

II. The total number electrons lost in the oxidation equal to total number of electrons gained in

the reduction

III. The same total charge of all ionic species on both sides of the reaction

IV. H2O present as a product or a reactant

Chapter 18 – Electrochemistry

2.

What is the total number of moles (n) of electrons exchanged between the oxidizing agent and the reducing agent in the

overall redox equation:

5 Ag+(aq) + Mn2+(aq) + 4H2O(l) → 5Ag(s) + MnO4–(aq) + 8H+(aq)

3.

What is the total number of moles (n) of electrons exchanged between the oxidizing agent and the reducing agent in the

overall redox equation:

Cr2O72-(aq) + 6Fe2+(aq) + 14H+(aq) → 2Cr3+(aq) + 6Fe3+(aq) + 7H2O(l)

Chapter 18 – Electrochemistry

4.

Complete and balance the following redox equation. When properly balanced using the smallest whole-number coefficients,

the coefficient of S is

H2S + HNO3 → S + NO (acidic solution)

5.

Complete and balance the following redox equation using the smallest whole-number coefficients. What is the coefficient of

Sn in the balanced equation?

Sn + HNO3 → SnO2 + NO2 + H2O (acidic solution)

Chapter 18 – Electrochemistry

6.

Complete and balance the following redox equation. What is the coefficient of H2O when the equation is balanced using the

set of smallest whole-number coefficients?

MnO4– + SO32– → Mn2+ + SO42– (acidic solution)

7.

Complete and balance the following redox equation. What is the coefficient of H2S when the equation is balanced using the

set of smallest whole-number coefficients?

H2S + MnO4– → Mn2+ + SO42– (acidic solution)

Chapter 18 – Electrochemistry

8.

Complete and balance the following redox equation. What is the coefficient of H2O when the equation is balanced with the

set of smallest whole-number coefficients?

H2O + MnO4– + I– → MnO2 + IO3– (basic solution)

9.

Complete and balance the following redox equation. What is the coefficient of OH– when the equation is balanced using the

set of smallest whole-number coefficients?

MnO4– + I– → MnO2 + IO3– (basic solution)

Chapter 18 – Electrochemistry

10.

Complete and balance the following redox equation using the set of smallest whole-number coefficients. Now sum the

coefficients of all species in the balanced equation. (Remember the coefficients that are equal to one.) The sum of the

coefficients is

BrO3–(aq) + Sb3+(aq) → Br–(aq) + Sb5+(aq) (acidic solution)

11.

Complete and balance the following redox equation that occurs in acidic solution using the set of smallest whole-number

coefficients. What is the sum of all the coefficients in the equation?

PbO2(s) + Cl– → Pb2+ + Cl2(g) (acidic solution)

Chapter 18 – Electrochemistry

12.

Complete and balance the following redox equation using the set of smallest whole-number coefficients. What is the sum of

the coefficients?

HI + HNO3 → I2 + NO (acidic solution)

13.

Complete and balance the following redox equation. The sum of the smallest whole-number coefficients is

MnO4– + H+ + Br– → Mn2+ + Br2 + H2O (acidic solution)

Chapter 18 – Electrochemistry

14.

Complete and balance the following redox equation. The sum of the smallest whole-number coefficients is

Bi(OH)3 + SnO22– → Bi + SnO32– (basic solution)

15.

Complete and balance the following redox equation. The sum of the smallest whole-number coefficients is

Br2 → BrO3– + Br– (basic solution)

Chapter 18 – Electrochemistry

16. Given the following notation for an electrochemical cell

Pt(s) | H2(g) | H+(aq) || Ag+(aq) | Ag(s)

what is the balanced overall (net) cell reaction?

Chapter 18 – Electrochemistry

17. Given the following cell diagram,

Al(s) | Al3+(aq) || Cd2+(aq) | Cd (s)

what is the balanced overall (net) cell reaction?

Chapter 18 – Electrochemistry

18.

Determine the cell diagram for the reaction below. Assume a platinum electrode is used when no other solid is present.

2Fe2+(aq) + Pb2+(aq) → 2Fe3+(aq) + Pb(s)

19.

Determine the cell diagram for the reaction below. Assume platinum electrodes are used when no other solid is present.

Cl2(g) + Sn2+(aq) → Sn4+(aq) + 2Cl–(aq)

Chapter 18 – Electrochemistry

20. Consider a Galvanic cell constructed from the following half cells, linked by an external

circuit and by a KCl salt bridge.

– an Al(s) electrode in 1.0 M Al(NO3)3 solution

– a Pb(s) electrode in 1.0 M Pb(NO3)2 solution

The balanced overall (net) cell reaction is

Chapter 18 – Electrochemistry

21. Which of the following is true concerning a galvanic cell?

22. Which of the following is true concerning a galvanic cell?

Chapter 18 – Electrochemistry

23. Consider an electrochemical cell constructed from the following half cells, linked by a

KCl salt bridge.

– a Fe electrode in 1.0 M FeCl2 solution

– a Sn electrode in 1.0 M Sn(NO3)2 solution

When the cell is running spontaneously, which choice includes only true statements and no

false ones?

24. Consider an electrochemical cell constructed from the following half cells, linked by a

KCl salt bridge.

– a Fe electrode in 1.0 M FeCl2 solution

– a Ni electrode in 1.0 M Ni(NO3)2 solution

When the cell is running spontaneously, which choice includes only true statements and no

false ones?

Chapter 18 – Electrochemistry

25.

A galvanic cell has the overall reaction:

Zn(s) + 2Eu(NO3)3(aq) → Zn(NO3)2(aq) + 2Eu(NO3)2(aq)

Which is the half reaction occurring at the anode?

Chapter 18 – Electrochemistry

26.

A galvanic cell has the overall reaction:

2Fe(NO3)2(aq) + Pb(NO3)2(aq) → 2Fe(NO3)3(aq) + Pb(s)

Which is the half reaction occurring at the cathode?

Chapter 18 – Electrochemistry

27.

Calculate the value of Ecell for the following reaction:

2Au(s) + 3Ca2+(aq) → 2Au3+(aq) + 3Ca(s)

28.

Calculate Ecell for a silver-aluminum cell in which the cell reaction is

Al(s) + 3Ag+(aq) → Al3+(aq) + 3Ag(s).

Chapter 18 – Electrochemistry

29.

Calculate Ecell for the following reaction:

2Fe2+(aq) + Cd2+(aq) → 2Fe3+(aq) + Cd(s)

30.

For the reaction, 2Cr2+ + Cl2(g) → 2Cr3+ + 2Cl–, Ecell is 1.78 V. Calculate Ecell for the related reaction Cr3+ + Cl– → Cr2+ +

1/2Cl2(g).

Chapter 18 – Electrochemistry

31.

For the reaction Ni2+(aq) + 2Fe2+(aq) → Ni(s) + 2Fe3+(aq), the standard cell potential Ecell is

32. Calculate the standard cell emf for the following cell:

Mg | Mg2+ || NO3– (acid soln)| NO(g) | Pt

Chapter 18 – Electrochemistry

33. Consider an electrochemical cell based on the following cell diagram:

Pt | Pu3+(aq), Pu4+(aq) || Cl2(g), Cl– (aq) | Pt

Given that the standard cell emf is 0.35 V and that the standard reduction potential of chlorine

is 1.36 V, what is the standard reduction potential E(Pu4+/Pu3+)?

34. Consider the following electrochemical cell:

U | U3+(aq) || Cl–(aq),Cl2(g) | Pt

If the standard cell emf is 3.16 V, what is the standard reduction potential for uranium?