Science Chemistry: Matter and Change

Science Chemistry: Matter and Change Glencoe Online
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 Problem of the Week

Solutions

Teachers Notes:

Problem 1:
a. Anode                        Cathode


b. Anode reaction: CH3OH + H2O → CO2 + 6 H+ + 6 e-
Cathode reaction: O2 + 4 H+ + 4 e- → 2 H2O
c. Since the electrons lost must equal the electrons gained
2(CH3OH + H2O → CO2 + 6 H+ + 6 e--) and
3(O2 + 4 H+ + 4 e- → 2 H2O)
2CH3OH + 2H2O → 2CO2 + 12 H+ + 12 e-
3O2 + 12 H+ + 12 e- → 6 H2O
Overall reaction: 2CH3OH + 3O2→ 2CO2 + 4H2O which can be simplified to:
CH3OH + 3/2O2→ CO22 + 2 H2O

Problem 2:
Overall reaction: NiOOH + MH → Ni(OH)2 + M
E°cell = 0.52 V - (-0.83 V) = 1.35 V.

Problem 3:
Overall reaction: Lix/graphite + Li1-xCoO2 → LixCO2 + Lix-1/graphite
E°cell = 0.5 V - (-3.0 V) = 3.5 V.

 
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Matter and Change