(a)[2]
An ideal gas is taken to be made of atoms or molecules that act as hard, identical spheres, move continuously, and experience elastic collisions. State two more assumptions of the kinetic theory of gases.
(b(i))[1]
Assuming helium-4 ($^{4}_{2}\text{He}$) is an ideal gas, show that the mass of a single helium-4 atom is $6.6 \times 10^{-24}\,\text{g}$.
(b(ii))[3]
The mean kinetic energy $E_{K}$ of an atom of an ideal gas is given by $E_{K} = \frac{3}{2}kT$. Calculate the root-mean-square (r.m.s.) speed of a helium-4 atom at a temperature of $27^{\circ}\text{C}$.