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5(a)Gas Laws Kinetic TheoryMedium1 mark

State what is represented by the Avogadro constant.

5(b)Gas Laws Kinetic TheoryMedium3 marks

A gas is in a sealed container that has a fixed volume. The thermodynamic temperature

T

of the gas is varied. Figure 5.1 shows how the pressure

p

of the gas varies with

N T

, where

N

is the number of molecules of the gas. Figure 5.2 shows how the mean-square speed

⟨ c^{2} ⟩

of the molecules of the gas varies with

T

. Figure 5.3 shows how the total kinetic energy

E_{K}

of all the molecules of the gas varies with

T

.

Figure 5.1, a graph of pressure $p$ (in $10^{4}\text{ Pa}$) against $NT$ (in $10^{26}\text{ K}$), a straight line through the origin rising to about $(8, 2.4)$

Figure 5.2, a graph of mean-square speed $\langle c^{2}\rangle$ (in $10^{6}\text{ m}^{2}\text{ s}^{-2}$) against thermodynamic temperature $T$ (in K), a straight line through the origin passing through $(200, 1.25)$ and reaching $(400, 2.50)$

Figure 5.3, a graph of total kinetic energy $E_{\text{K}}$ (in $10^{4}\text{ J}$) against thermodynamic temperature $T$ (in K), a straight line through the origin reaching about $(400, 1.3)$

Determine three conclusions about the gas that can be drawn from Figure 5.1, Figure 5.2 and Figure 5.3. The conclusions may be qualitative or quantitative.

Answer

0 words

5(c)(i)Gas Laws Kinetic TheoryEasy1 mark

One assumption of the kinetic theory of gases is that the volume of the molecules is negligible compared with the volume of the gas. State, with a reason, whether this assumption applies to the gas in 5(b).

Answer

0 words

5(c)(ii)Gas Laws Kinetic TheoryEasy2 marks

State two other assumptions of the kinetic theory of gases.

Answer

0 words

February/March 2026 Paper 42

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