DP Chemistry (last assessment 2024)

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Question 19M.2.sl.TZ2.1a

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

Ethyne, C2H2, reacts with oxygen in welding torches.

(a)

Write an equation for the complete combustion of ethyne.

[1]

Markscheme

C2H2 (g) + 2.5O2 (g) → 2CO2 (g) + H2O (l)
OR
2C2H2 (g) + 5O2 (g) → 4CO2 (g) + 2H2O (l)  [✔]

Examiners report

Almost all candidates recognized the products of the complete combustion of ethyne, and over two thirds managed to balance the equation. It was good to see candidates using integers for the balancing.

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