DP Chemistry (first assessment 2025)

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Question 22M.2.SL.TZ1.c(i)

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Date May 2022 Marks available [Maximum mark: 1] Reference code 22M.2.SL.TZ1.c(i)
Level SL Paper 2 Time zone TZ1
Command term Evaluate Question number c(i) Adapted from N/A
c(i).
[Maximum mark: 1]
22M.2.SL.TZ1.c(i)

Evaluate whether this, rather than the loss of product, could explain the yield found in (b)(iii).

[1]

Markscheme

yes
AND
«each Mg combines with 23 N, so» mass increase would be 14x23 which is less than expected increase of 16x
OR
3 mol Mg would form 101g of Mg3N2 but would form 3 x MgO = 121 g of MgO
OR
0.2614 mol forms 10.536 g of MgO, but would form 8.796 g of Mg3N2 ✔

 

Accept Yes AND “the mass of N/N2 that combines with each g/mole of Mg is lower than that of O/O2”

Accept YES AND “molar mass of nitrogen less than of oxygen”.

Examiners report

This proved to be a very difficult question to answer in the quantitative manner required, with hardly any correct responses.

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