DP Physics (first assessment 2025)

Question EXE.2.SL.TZ0.10

Date	Example questions Example questions	Marks available	[Maximum mark: 7]	Reference code	EXE.2.SL.TZ0.10
Level	SL	Paper	2	Time zone	TZ0
Command term	Calculate, Determine, Explain	Question number	10	Adapted from	N/A

10.

[Maximum mark: 7]

EXE.2.SL.TZ0.10

A sealed container of volume 0.35 m³ holds 1.6 mol of a monoatomic gas that can be treated as ideal. The temperature of the gas is 320 K.

One mole of the gas has a mass of 4.0 × 10⁻² kg.

(a)

Calculate the pressure of the gas in the container.

[1]

Markscheme

$p = \frac{n R T}{V}$ seen $= 12 kPa$ ✓

(b)

Determine the mass of the gas in the container.

[1]

Markscheme

$6.4 \times 10^{- 2} kg$ ✓

(c)

Calculate the average translational speed of the gas particles.

[1]

Markscheme

$v = \sqrt{\frac{3 P V}{M}} = 450 {m s}^{- 1}$ ✓

(d)

The temperature of the gas in the container is increased.

Explain, using the kinetic theory, how this change leads to a change in pressure in the container.

[4]

Markscheme

increased temperature means increased average KE and hence increased average translational speed ✓

This increases the momentum transfer at the walls for each collision / mv is greater per collision ✓

This increases the frequency of collisions at the walls / particles cover the distance between walls more quickly ✓

Ideas that $F_{wall} = \frac{Δ p}{Δ t}$ AND $P = \frac{F}{A}$ (can be in words) so that force increases and pressure increases ✓

Syllabus sections