HW10 - Electrochemical Stoichiometry

Question 11.5 pts

What is the standard cell potential of a battery made from the half reactions below?

2H+ + 2e- \longrightarrow H2                     E° = 0.00V

O2 + 4H+ + 4e- \longrightarrow 2H2O        E° = +1.23 V

  1. -2.46
  2. -1.23
  3. 2.46
  4. 1.23

Question 21.5 pts

In an electrolytic cell, the negative terminal is the (cathode/anode) and is the site of the (oxidation/reduction) half-reaction.
  1. anode, reduction
  2. cathode, oxidation
  3. cathode, reduction
  4. anode, oxidation

Question 31.5 pts

Consider the galvanic cell:

Ag(s) | AgCl(s) | Cl-(aq) || Cl-(aq) | Hg2Cl2(s) | Hg(l)

What is the smallest possible integer coefficient of Ag(s) in the combined balanced equation?

  1. 3
  2. 4
  3. 1
  4. 2

Question 41.5 pts

Silver is plated on copper by immersing a piece of copper into a solution containing silver (I) ions. In the plating reaction, copper...
  1. is oxidized and is the reducing agent.
  2. is reduced and is the oxidizing agent.
  3. is oxidized and is the oxidizing agent.
  4. is reduced and is the reducing agent.

Question 51.5 pts

What is the E° for the following electrochemical cell where Zn is the cathode?

Fe | Fe2+ (1.0 M) || Zn2+ (1.0 M) | Zn

E°(Zn) = -0.76, E°(Fe) = -0.44

  1. +0.32
  2. -1.20
  3. +1.20
  4. -0.32

Question 61.5 pts

Which of the metals in the list below will react with 1M H2SO4 to produce hydrogen gas?

Na+ + 1e- \longrightarrow Na            E° = -2.714

Cd2+ + 2e- \longrightarrow Cd          E° = -0.403

Pb2+ + 2e- \longrightarrow Pb           E° = -0.126

Cu2+ + 2e- \longrightarrow Cu           E° = +0.337

  1. Na, Cd, Pb, and Cu
  2. Na, Cd, and Pb only
  3. Na and Cd only
  4. Cu only

Question 71.5 pts

Consider the voltaic cell:

Pt | Sn2+ (0.10 M), Sn4+ (0.0010 M) || Ag+ (0.010 M) | Ag

Sn4+ + 2e- \longrightarrow Sn2+           E° = +0.15 V

Ag+ + 1e- \longrightarrow Ag(s)            E° = +0.80 V

The electrons flow in the external circuit from...

  1. Sn to Ag
  2. Ag to Pt
  3. Sn2+ to Ag+
  4. Pt to Ag

Question 81.5 pts

Using the standard potential tables, what is the largest approximate E° value that can be achieved when two half-cell reactions are combined to form a battery?
  1. 3 V
  2. -6 V
  3. 6 V
  4. -3 V

Question 91.5 pts

Consider the cell:

Zn(s) | Zn2+(aq) || Cl-(aq) | AgCl(s) | Ag(s)

Calculate E°.

  1. -1.20 V
  2. +0.98 V
  3. +1.20 V
  4. +0.54 V

Question 102.0 pts

Which species will oxidize Cr2+ (E°red = -0.407) but not Mn2+ (E°red = +1.224)?
  1. Pb4+ (E°red = +1.68)
  2. O3 in acid (E°red = +2.076)
  3. Zn2+ (E°red = -0.762)
  4. Fe2+ (E°red = -0.771)
  5. V3+ (E°red = -0.255)

Question 111.5 pts

If the standard potentials for the couples Cu2+|Cu, Ag+|Ag, and Fe2+|Fe are +0.34, +0.80, and -0.44 V respectively, which is the strongest reducing agent?
  1. Cu2+
  2. Fe2+
  3. Cu
  4. Ag
  5. Fe
  6. Ag+

Question 121.5 pts

For the cell diagram below:

Cd(s) | CdSO4(aq) || Hg2SO4 | Hg(l)

What reaction occurs at the cathode?

  1. 2Cd(l) + SO42-(aq) \longrightarrow CdSO4(s) + 2e-
  2. 2Hg(l) + SO42-(aq) \longrightarrow Hg2SO4(s) + 2e-
  3. Hg2SO4(s) + 2e- \longrightarrow 2Hg(l) + SO42-(aq)
  4. CdSO4(s) + 2e- \longrightarrow 2Cd(l) + SO42-(aq)

Question 132.0 pts

Consider the cell diagram below:

Mg(s) | Mg2+(aq) || Au+(aq) | Au(s)

Mg2+ + 2e- \longrightarrow Mg      E° = -2.36

Au+ + e- \longrightarrow Au           E° = +1.69

What is the cathode and what is the cell type?

  1. Mg(s); a voltaic cell
  2. Au(s); an electrolytic cell
  3. Mg(s); an electrolytic cell
  4. Au(s); a voltaic cell

Question 141.5 pts

Consider the half-reactions:

Mn2+ + 2e- \longrightarrow Mn      E° = -1.029 V

Ga3+ + 3e- \longrightarrow Ga       E° = -0.560 V

Fe2+ + 2e- \longrightarrow Fe        E° = -0.409 V

Sn2+ + 2e- \longrightarrow Sn        E° = -0.136 V

Using the redox couples to establish a voltaic cell, which reaction would be non-spontaneous?

  1. 2Ga + 3Sn2+ \longrightarrow 2Ga3+ + 3Sn
  2. Sn2+ + Mn \longrightarrow Sn + Mn2+
  3. Sn2+ + Fe \longrightarrow Sn + Fe2+
  4. 2Ga3+ + 3Fe \longrightarrow 2Ga + 3Fe2+
  5. Fe2+ + Mn \longrightarrow Mn2+ + Fe

Question 151.5 pts

Find the standard emf of the given cell diagram:

Cu(s) | Cu2+(aq) || Au+(aq) | Au(s)

Cu2+ + 2e- \longrightarrow Cu     E° = +0.34 V

Au+ + e- \longrightarrow Au         E° = +1.69 V

  1. +2.03 V
  2. -1.35 V
  3. -2.03 V
  4. +1.35 V

Question 162.0 pts

Which species will REDUCE Ag+ but not Fe2+?
  1. Cr
  2. K
  3. Co2+
  4. H2

Question 171.5 pts

If the table of standard reduction potentials is ordered with the strongest reducing agents at the top, how are the reduction potentials ordered (from top to bottom)?
  1. from most spontaneous to least spontaneous
  2. from most common to least common
  3. from most negative to most positive
  4. from most positive to most negative

Question 181.5 pts

Which species is the weakest reducing agent in the table of half-reactions?
  1. F-
  2. F2
  3. Li+
  4. Li

Question 191.5 pts

If the two half-reactions below were used to make an electrolytic cell, what species would be consumed at the anode?

Au3+(aq) + 3e- \longrightarrow Au(s)         E° = +1.50

I2(s) + 2e- \longrightarrow 2I-(aq)              E° = +0.53

  1. I-(aq)
  2. Au3+(aq)
  3. I2(s)
  4. Au(s)













CH302 · 50520 Principles of Chemistry II


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