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Electrode potentials and electrochemical cells (A-level only)

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Question 15

This question is about fuel cells.

In an ethanol–oxygen fuel cell, the overall reaction is:

C2H5OH(l)+3O2(g)→2CO2(g)+3H2O(l)EMF=+1.15 V \text{C}_2\text{H}_5\text{OH}(l) + 3\text{O}_2(g) \rightarrow 2\text{CO}_2(g) + 3\text{H}_2\text{O}(l) \quad \text{EMF} = +1.15\text{ V} C2​H5​OH(l)+3O2​(g)→2CO2​(g)+3H2​O(l)EMF=+1.15 V
1.

At the positive electrode, oxygen reacts with hydrogen ions to form water. Give a half-equation for this reaction.

[1]
2.

At the negative electrode, ethanol reacts with water to produce carbon dioxide and hydrogen ions. Give a half-equation for this reaction.

[1]
3.

The standard electrode potential for the CO2/C2H5OH\text{CO}_2 / \text{C}_2\text{H}_5\text{OH}CO2​/C2​H5​OH electrode is +0.08 V+0.08\text{ V}+0.08 V. Calculate the standard electrode potential for the O2/H2O\text{O}_2 / \text{H}_2\text{O}O2​/H2​O electrode.

[2]
4.

State why a fuel cell does not need to be electrically recharged.

[1]
5.

Suggest one advantage of using ethanol, rather than hydrogen, in a fuel cell for use in cars.

[1]

Electrode potentials and electrochemical cells (A-level only) Questions

  1. A Level
  2. /Chemistry
  3. /Electrode potentials and electrochemical cells (A-level only)