IB Chemistry HL 1.3.5 Fuel cells Question Bank

Practise IB Chemistry HL 1.3.5 by applying fuel cells to exam-style questions.

[Maximum number: 5]

As well as being burnt, methanol can also be used to provide electricity through a fuel cell. A schematic diagram of such a fuel cell, that depends on the transfer of hydrogen ions between the electrodes, is shown below.

Figure for Question 1.3.5—Fuel cells question 1 — IB Chemistry HL

(a)

Deduce half-equations for the reactions at the two electrodes and hence the equation for the overall reaction.

Anode (negative electrode):

Cathode (positive electrode):

Overall:

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Anode:
$\mathrm{CH}_{3}\mathrm{OH}(aq)+\mathrm{H}_{2}\mathrm{O}(l) \rightarrow \mathrm{CO}_{2}(aq)+6\mathrm{H}^{+}(aq)+6e^{-}$

Cathode:
$\mathrm{O}_{2}(aq)+4\mathrm{H}^{+}(aq)+4e^{-} \rightarrow 2\mathrm{H}_{2}\mathrm{O}(l)$

Overall:
$2\mathrm{CH}_{3}\mathrm{OH}(aq)+3\mathrm{O}_{2}(g) \rightarrow 2\mathrm{CO}_{2}(aq)+4\mathrm{H}_{2}\mathrm{O}(l)$

(b)

Identify one factor that affects the voltage of a cell and a different factor that affects the current it can deliver.

Voltage:

Current:

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1.3.5—Fuel cells question 1

Question (a)

Question (b)