DP Chemistry (last assessment 2024)

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Question 19M.2.sl.TZ2.1b(ii)

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Date May 2019 Marks available [Maximum mark: 1] Reference code 19M.2.sl.TZ2.1b(ii)
Level sl Paper 2 Time zone TZ2
Command term Compare Question number b(ii) Adapted from N/A
b(ii).
[Maximum mark: 1]
19M.2.sl.TZ2.1b(ii)

Ethyne, C2H2, reacts with oxygen in welding torches.

(b(ii))

Compare, giving a reason, the length of the bond between the carbon atoms in ethyne with that in ethane, C2H6.

[1]

Markscheme

«ethyne» shorter AND a greater number of shared/bonding electrons
OR
«ethyne» shorter AND stronger bond  [✔]

Examiners report

A very well answered question. The vast majority of candidates understood that triple bonds are stronger than single bonds and result in a shorter bond length. It was disappointing, however, to see a considerable number of candidates stating that ethane has a double bond.

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