Nuclear ChemistryIB MYP Chemistry: Topic test

20 questions, 54 marks

IB MYP Chemistry

Nuclear Chemistry topic test

Total 54 marks

Name

Class

Date

1
A physics technician in Lyon tests three sealed radioactive sources, X, Y and Z, with a Geiger counter. Source X is completely stopped by a sheet of paper. Source Y passes through paper but is completely stopped by 3 mm of aluminium. Radiation from source Z passes through both, and its count rate falls only slightly even behind a thick block of lead.
(a)
Which row correctly identifies the radiation from sources X, Y and Z?
[1 mark]
AX is beta, Y is alpha, Z is gamma
BX is gamma, Y is beta, Z is alpha
CX is alpha, Y is gamma, Z is beta
DX is alpha, Y is beta, Z is gamma
(b)
Which statement about the charge of the three types of radiation is correct?
[1 mark]
AAlpha is negative, beta is positive and gamma has no charge
BAlpha is positive, beta is negative and gamma has no charge
CAll three types of radiation are positively charged
DAlpha is positive, beta has no charge and gamma is negative
(c)
Explain why radioactive sources are kept in lead-lined boxes and handled with long tongs.
[2 marks]
Total for question 1: 4 marks
2
Radium-226 has 88 protons. It was once used in luminous paint at a watch factory. A radium-226 nucleus is unstable and decays by emitting an alpha particle to form radon. Lead-210, which has 82 protons, is another unstable nucleus that decays by emitting a beta particle.
(a)
Which is the correct mass number and atomic number of the radon nucleus formed when radium-226 emits an alpha particle?
[1 mark]
AMass number 222, atomic number 86
BMass number 222, atomic number 88
CMass number 226, atomic number 86
DMass number 230, atomic number 90
(b)
What is the atomic number of the nucleus formed when lead-210 emits a beta particle?
[1 mark]
A81
B82
C83
D84
(c)
Describe what happens inside a lead-210 nucleus when it emits a beta particle.
[2 marks]
Total for question 2: 4 marks
3
A sterilisation plant in Penang, Malaysia, passes boxes of packaged surgical gloves along a conveyor through a chamber that contains a cobalt-60 source. The source had an activity of 800 TBq when it was new. Cobalt-60 has a half-life of about 5 years.
(a)
Calculate the activity of the source after 15 years. Show your working.
[3 marks]
(b)
Explain why cobalt-60 is suitable for sterilising the packaged gloves, and why the plant must eventually replace the source.
[4 marks]
Total for question 3: 7 marks
4
A hospital in Perth, Australia, scans patients' bones using a radioactive isotope with a half-life of 6 hours. A delivery of the isotope arrives at 06:00 with an activity of 960 MBq. A small dose is injected into each patient, and the leftover isotope is stored in a lead-lined cupboard until it is safe to dispose of. Some residents living near the hospital have asked the council to ban the storage of radioactive materials there.
(a)
Explain why an isotope with a half-life of 6 hours is suitable for scanning patients, and how the hospital should deal with the leftover isotope.
[6 marks]
(b)
Evaluate the residents' request to ban the storage of radioactive materials at the hospital. Consider the benefits and risks and give a justified conclusion.
[6 marks]
Total for question 4: 12 marks
5
A geologist in Cornwall, England, uses a Geiger counter. In her laboratory with no source present it reads about 30 counts per minute. In a granite cellar, also with no source present, it reads about 75 counts per minute. Back in the laboratory, she places a sealed alpha source 10 cm from the tube and the reading stays at about 30 counts per minute.
(a)
Which is a source of the 30 counts per minute recorded in the laboratory with no source present?
[1 mark]
ACosmic rays from space
BRadiation from the Geiger counter's battery
CAlpha particles from the sealed source
DHeat radiation from the laboratory lamp
(b)
Why does the reading not rise when the alpha source is placed 10 cm from the tube?
[1 mark]
AAlpha particles are not ionising
BAlpha particles have no charge so the tube cannot detect them
CAlpha particles are too penetrating to be stopped by the tube
DAlpha particles are absorbed by a few centimetres of air
(c)
Suggest why the Geiger counter reads higher in the granite cellar than in the laboratory.
[2 marks]
Total for question 5: 4 marks
6
A nuclear power station in Finland releases energy from uranium. Its spent fuel is sealed in steel containers and stored deep underground. In France, scientists are building an experimental reactor that tries to copy the process that releases energy in the Sun.
(a)
Which process releases energy from the uranium in the Finnish power station?
[1 mark]
ATwo small nuclei join to form a larger nucleus
BA large nucleus splits into two smaller nuclei
CA nucleus emits only gamma rays and does not change
DUranium burns in oxygen
(b)
Which process does the experimental reactor in France try to copy?
[1 mark]
AA large nucleus splits into two smaller nuclei
BA nucleus emits a beta particle
CTwo light nuclei join to form a heavier nucleus
DHydrogen burns in oxygen to form water
(c)
Explain why spent fuel must be stored safely for thousands of years.
[2 marks]
Total for question 6: 4 marks
7
Engineers in Mumbai look for a leak in a buried water main. They add a small amount of sodium-24 to the water and walk along the route with detectors above the ground. Sodium-24 has 11 protons and a half-life of 15 hours. It decays by emitting a beta particle to form an isotope of magnesium. The first batch of sodium-24 has an activity of 320 kBq.
(a)
Write the nuclear equation for the beta decay of sodium-24.
[3 marks]
(b)
The water must not be used by customers until the activity of the sodium-24 has fallen to 40 kBq. Calculate how long this takes. Explain why a tracer with a half-life of 15 hours is better than one with a half-life of 15 days.
[4 marks]
Total for question 7: 7 marks
8
A physics teacher in Auckland wants her class to find out how the thickness of aluminium affects the radiation reaching a Geiger counter. She has a sealed source that emits beta radiation, a Geiger counter, a stopwatch, and aluminium sheets of thickness 1 mm, 2 mm and 3 mm. Some parents have written to the school to say that schools should not be allowed to keep radioactive sources at all.
(a)
Design an investigation to find how the thickness of aluminium affects the count rate. Include a hypothesis with a reason, the variables, a method and a safety precaution.
[6 marks]
(b)
Evaluate the parents' view that schools should not be allowed to keep radioactive sources. Consider the benefits and risks and give a justified conclusion.
[6 marks]
Total for question 8: 12 marks

End of questions

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).