(a)[1]
State the meaning of the term ideal gas.
(b(i))[2]
An ideal gas is contained in a storage cylinder of volume $3.0 \times 10^{-4}\ \text{m}^3$. Its temperature is $23\ ^\circ\text{C}$ and its pressure is $5.0 \times 10^7\ \text{Pa}$. Show that the amount of gas in the cylinder is $6.1\ \text{mol}$.
(b(ii))[4]
The gas leaks slowly out of the cylinder, and after a time of $35$ days the pressure has fallen by $0.40\%$. The temperature stays constant. Calculate the average rate, in atoms per second, at which gas atoms escape from the cylinder.