DP Chemistry (last assessment 2024)

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Question 18M.3.hl.TZ1.b.ii

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Date May 2018 Marks available [Maximum mark: 3] Reference code 18M.3.hl.TZ1.b.ii
Level hl Paper 3 Time zone TZ1
Command term Explain Question number b.ii Adapted from N/A
b.ii.
[Maximum mark: 3]
18M.3.hl.TZ1.b.ii

Modern electric cars store their energy in lithium ion batteries.

The carbon footprint of electric cars depends on how the electricity is produced. Nuclear fission of 235U is one source of electrical energy that has a minimal carbon footprint.

Explain how the proportion of 235U in natural uranium is increased.

[3]

Markscheme

uranium converted to uranium hexafluoride/UF6 gas

 

ALTERNATIVE 1:

gas «allowed to» diffuse

lower mass isotope/235U passes through more rapidly

 

ALTERNATIVE 2:

use of centrifuge

 

higher mass isotope/238U moves/closer to outside of centrifuge

OR

lower mass isotope/235U stays in/removed from middle of centrifuge

 

[3 marks]

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