DP Chemistry (last assessment 2024)
Question 19N.3.sl.TZ0.11b
| Date | November 2019 | Marks available | [Maximum mark: 2] | Reference code | 19N.3.sl.TZ0.11b |
| Level | sl | Paper | 3 | Time zone | TZ0 |
| Command term | Calculate | Question number | b | Adapted from | N/A |
b.
[Maximum mark: 2]
19N.3.sl.TZ0.11b
Consider the following data for butane and pentane at STP.
(b)
In a natural gas power station, 1.00 tonne of natural gas produces 2.41 × 104 MJ of electricity.
Calculate the percentage efficiency of the power station.
1 tonne = 1000 kg
Specific energy of natural gas used = 55.4 MJ kg−1
[2]
Markscheme
«energy input =» 5.54 ×104 «MJ» ✔
«efficiency = » 43.5 «%» ✔
NOTE: Award [2] for correct final answer.
