DP Physics (first assessment 2025)

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Question 22M.2.SL.TZ1.2c

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Date May 2022 Marks available [Maximum mark: 2] Reference code 22M.2.SL.TZ1.2c
Level SL Paper 2 Time zone TZ1
Command term Discuss Question number c Adapted from N/A
c.
[Maximum mark: 2]
22M.2.SL.TZ1.2c
(c)

Discuss, with reference to the molecules in the liquid, the difference between milk at 11 °C and milk at 84 °C.

[2]

Markscheme

the temperature has increased so the internal energy / « average » KE «of the molecules» has increased OR temperature is proportional to average KE «of the molecules». ✓

«therefore» the «average» speed of the molecules or particles is higher OR more frequent collisions « between molecules » OR spacing between molecules has increased OR average force of collisions is higher OR intermolecular forces are less OR intermolecular bonds break and reform at a higher rate OR molecules are vibrating faster. ✓

Examiners report

This was generally well answered. Most HL candidates linked the increase in temperature to the increase in the kinetic energy of the molecules and were able to come up with a consequence of this change (such as the molecules moving faster). SL candidates tended to focus more on consequences, often neglecting to mention the change in KE.