DP Chemistry (last assessment 2024)

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Question 19M.3.hl.TZ2.d

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Date May 2019 Marks available [Maximum mark: 2] Reference code 19M.3.hl.TZ2.d
Level hl Paper 3 Time zone TZ2
Command term Calculate Question number d Adapted from N/A
d.
[Maximum mark: 2]
19M.3.hl.TZ2.d

This question is about nuclear reactions.

Calculate the half-life of an isotope whose mass falls from 5.0 × 10−5 g to 4.0 × 10−5 g in 31.4 s, using section 1 of the data booklet.

[2]

Markscheme

«N = N0e–λt»

λ«=  − ln ⁡ ( N N 0 ) t = − ln ⁡ ( 4.0 × 10 − 5 5.0 × 10 − 5 ) 31.4  s »

= 7.106 × 10–3 s–1  [✔]

«  t 1 2 = ln ⁡ 2 λ =» 98/97.5 «s» [✔]

 

Note: Award [2] for correct final answer.

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