| Date | May 2018 | Marks available | 3 | Reference code | 18M.3.hl.TZ2.13 |
| Level | HL | Paper | 3 | Time zone | TZ2 |
| Command term | Determine | Question number | 13 | Adapted from | N/A |
Question
Crude oil is a useful energy resource.
Fuel cells have a higher thermodynamic efficiency than octane. The following table gives some information on a direct methanol fuel cell.
Determine the thermodynamic efficiency of a methanol fuel cell operating at 0.576 V.
Use sections 1 and 2 of the data booklet.
Markscheme
n = 6
«ΔGΘ = –nFEΘ = 6 mol × 96 500 C mol–1 × 0.576 V =» –333 504 J/–334 kJ
«Efficiency = \(\frac{{\Delta G}}{{\Delta H}} = \frac{{ - 334}}{{ - 726}}\) =» 0.459/45.9%
Award [3] for correct final answer.
[3 marks]
Examiners report
[N/A]
