DP Chemistry (first assessment 2025)
Question 19N.2.SL.TZ0.11a
| Date | November 2019 | Marks available | [Maximum mark: 3] | Reference code | 19N.2.SL.TZ0.11a |
| Level | SL | Paper | 2 | Time zone | TZ0 |
| Command term | Discuss | Question number | a | Adapted from | N/A |
a.
[Maximum mark: 3]
19N.2.SL.TZ0.11a
(a)
Discuss the data.
[3]
Markscheme
«similar specific energy and» pentane has «much» larger energy density ✔
Any two for [2 max]:
similar number of bonds/«C and H» atoms in 1 kg «leading to similar specific energy»
OR
only one carbon difference in structure «leading to similar specific energy» ✔
NOTE: Accept “both are alkanes” for M2.
pentane is a liquid AND butane is a gas «at STP» ✔
NOTE: Accept “pentane would be easier to transport”.
1 m3 of pentane contains greater amount/mass than 1 m3 of butane ✔
NOTE: Accept “same volume” for “1 m3” and “more moles” for “greater amount” for M4.
Syllabus sections
Reactivity 1. What drives chemical reactions? » Reactivity 1.3—Energy from fuels » Reactivity 1.3.3—Fossil fuels include coal, crude oil and natural gas, which have different advantages and disadvantages. Evaluate the amount of carbon dioxide added to the atmosphere when different fuels burn. Understand the link between carbon dioxide levels and the greenhouse effect.