DP Chemistry (last assessment 2024)

Test builder »

Question 21M.2.hl.TZ2.b(iii)

Select a Test
Date May 2021 Marks available [Maximum mark: 2] Reference code 21M.2.hl.TZ2.b(iii)
Level hl Paper 2 Time zone TZ2
Command term Determine Question number b(iii) Adapted from N/A
b(iii).
[Maximum mark: 2]
21M.2.hl.TZ2.b(iii)

Limestone can be converted into a variety of useful commercial products through the lime cycle. Limestone contains high percentages of calcium carbonate, CaCO3.

Thermodynamic data for the decomposition of calcium carbonate is given.

Determine the temperature, in K, at which the decomposition of calcium carbonate becomes spontaneous, using b(i), b(ii) and section 1 of the data booklet.

(If you do not have answers for b(i) and b(ii), use ΔH = 190 kJ and ΔS = 180 J K−1, but these are not the correct answers.)

[2]

Markscheme

«spontaneous» if ΔG = ΔH − TΔS < 0
OR
ΔH < TΔS ✓

«T >179 kJ0.16 kJ K-1=» 1112 «K» ✓


Award [2] for correct final answer.

Accept “1056 K” if both of the incorrect values are used to solve the problem.

Do not award M2 for any negative T value.

Syllabus sections