DP Chemistry (first assessment 2025)

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Question 19M.2.SL.TZ2.2a

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Date May 2019 Marks available [Maximum mark: 3] Reference code 19M.2.SL.TZ2.2a
Level SL Paper 2 Time zone TZ2
Command term Determine Question number a Adapted from N/A
a.
[Maximum mark: 3]
19M.2.SL.TZ2.2a
(a)

Determine from the graph the rate of reaction at 20 s, in cm3 s−1, showing your working.

[3]

Markscheme

tangent drawn to curve at t = 20 s  [✔]

slope/gradient calculation  [✔]

0.35 «cm3 s–1»  [✔]

 

Note: Accept values in the range 0.32–0.42 «cm3 s–1».

Examiners report

This question was challenging for many students. Quite a few candidates did draw a tangent line at 20s for 1 mark, show a slope/gradient calculation of the line for 1 mark, and had a reasonable final value for the final mark. Some candidates only found the average rate by finding the ratio of the value at that data point and received one mark (16/20=0.80 cm3 s-1). Candidates also received one mark if they had a correct answer with no work since the question clearly asked students to show their work.

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