Question

both propane and CO2 diffuse at same rate under identical conditions of temperature and pressure. why?

Answer 1

According to Graham's Law, effusion of a gas is inversely proportional to the square root of the molar mass of the gas:$\frac{{\mathrm{Rate}}_{{\mathrm{C}}_3{\mathrm{H}}_8}}{{\mathrm{Rate}}_{{\mathrm{CO}}_2}}=\sqrt{\frac{{\mathrm{M}}_{{\mathrm{CO}}_2}}{{\mathrm{M}}_{{\mathrm{C}}_3{\mathrm{H}}_8}}}$
Since the molar mass of propane and carbon dioxide =44 g/mol their rate of diffusion is also the same.