(a) State what is meant by an ideal gas.

(b) A storage cylinder for ideal gas has a volume of 3.0 × 10⁻⁴ m³. The gas is at a temperature of 23 °C and a pressure of 5.0 × 10⁷ Pa.

(i) Show that the amount of gas in the cylinder is 6.1 mol.

(ii) The gas leaks slowly from the cylinder so that, after a time of 35 days, the pressure has reduced by 0.40%. Temperature remains constant.

Calculate the average rate, in atoms per second, at which gas atoms escape from the cylinder.