DP Chemistry (last assessment 2024)

Test builder »

Question 19M.3.hl.TZ1.c

Select a Test
Date May 2019 Marks available [Maximum mark: 2] Reference code 19M.3.hl.TZ1.c
Level hl Paper 3 Time zone TZ1
Command term Calculate Question number c Adapted from N/A
c.
[Maximum mark: 2]
19M.3.hl.TZ1.c

Uranium-235, 235U, is bombarded with a neutron causing a fission reaction.

The daughter product, 89Kr, has a half-life of 3.15 min.

Calculate the time required, in minutes, for its radioactivity to fall to 10% of its initial value, using section 1 of the data booklet.

[2]

Markscheme

λ ( = ln ⁡ 2 t 1 2 = ln ⁡ 2 3.15 ) = 0.220 «min–1»    [✔]

t ( = − 1 λ ln ⁡ N N 0 = − ln ⁡ 0.1 0.220 ) = 10.5 «min»    [✔]

 

Note: Award [2] for correct final answer.

Examiners report

The calculation of time taken for radioactivity to fall to 10% of its initial value was answered very well.

Syllabus sections