DP Chemistry (last assessment 2024)
Question 22M.2.sl.TZ2.4b
| Date | May 2022 | Marks available | [Maximum mark: 2] | Reference code | 22M.2.sl.TZ2.4b |
| Level | sl | Paper | 2 | Time zone | TZ2 |
| Command term | State | Question number | b | Adapted from | N/A |
b.
[Maximum mark: 2]
22M.2.sl.TZ2.4b
Carbon forms many compounds.
(b)
State two features showing that propane and butane are members of the same homologous series.
[2]
Markscheme
same general formula / CnH2n+2 ✔
differ by CH2/common structural unit ✔
Accept "similar chemical properties".
Accept “gradation/gradual change in physical properties”.
Examiners report
About two-thirds of the candidates scored one of the two marks and stronger candidates scored both. The most common answers were the same general formula/CnH2n+2, the difference between the compounds was CH2 and similar chemical properties. The same functional group was not accepted since alkanes do not have a functional group. Some candidates only stated that they are saturated hydrocarbons not gaining any marks.
