DP Chemistry (last assessment 2024)

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Question 22M.2.hl.TZ2.b

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Date May 2022 Marks available [Maximum mark: 2] Reference code 22M.2.hl.TZ2.b
Level hl Paper 2 Time zone TZ2
Command term State Question number b Adapted from N/A
b.
[Maximum mark: 2]
22M.2.hl.TZ2.b

Carbon forms many compounds.

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

This easy question was quite well answered; same/similar physical properties and empirical formula were common errors.

Candidates misinterpreted the question and mentioned CH3+, i.e., the lost fragment; the other very common error was -COOH which shows a complete lack of understanding of MS considering the question is about butane so O should never appear.

Syllabus sections