Explain qualitatively how molecular movement causes the pressure exerted by a gas.
The density of neon gas at a temperature of 
and a pressure of 
is 
. Neon may be assumed to be an ideal gas. Calculate the root-mean-square (r.m.s.) speed of neon atoms at
,
.
The calculations in (b) are based on the density for neon being . Suggest the effect, if any, on the root-mean-square speed of changing the density at constant temperature.
