Physics 9702 · AS & A Level · Kinetic theory of gases

Kinetic theory of gases — practice question

(a)[2]

The kinetic theory of gases rests on several assumptions about gas molecules. State the assumption linked to the molecules' volume.

(b)

An ideal gas has a volume of $2.40 \times 10^{-2}\text{ m}^3$ at a pressure of $4.60 \times 10^{5}\text{ Pa}$ and a temperature of $23^{\circ}\text{C}$.

(b(i))[3]

Calculate how many molecules are in the gas.

(b(ii))[3]

Each molecule has a diameter of about $3 \times 10^{-10}\text{ m}$. Estimate the overall volume of the gas molecules.

(c)[1]

Using your answer in (b)(ii), explain why the assumption in (a) is reasonable.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: The combined volume of the molecules is negligible

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