DP Physics (last assessment 2024)
Question 18M.2.HL.TZ2.2b.ii
| Date | May 2018 | Marks available | [Maximum mark: 2] | Reference code | 18M.2.HL.TZ2.2b.ii |
| Level | HL | Paper | 2 | Time zone | TZ2 |
| Command term | Explain | Question number | b.ii | Adapted from | N/A |
b.ii.
[Maximum mark: 2]
18M.2.HL.TZ2.2b.ii
The volume of the gas in (a) is increased to 6.8 × 10–4 m3 at constant temperature.
(b.ii)
Explain, in terms of molecular motion, this change in pressure.
[2]
Markscheme
«volume has increased and» average velocity/KE remains unchanged
«so» molecules collide with the walls less frequently/longer time between collisions with the walls
«hence» rate of change of momentum at wall has decreased
«and so pressure has decreased»
The idea of average must be included
Decrease in number of collisions is not sufficient for MP2. Time must be included.
Accept atoms/particles.
[2 marks]
