Two ideal gases, helium and oxygen, are maintained in separate containers at identical temperature and pressure. The ratio of the mass density of helium to that of oxygen is:

Step-by-step solution

The ideal gas equation in terms of mass density is given by P = RT M₀ , where M₀ is the molar mass of the gas. Rearranging for density, we get = P M₀ RT . Since the pressure P and temperature T are identical for both gases, the mass density is directly proportional to the molar mass ( M₀ ). The molar mass of monatomic helium ( He ) is 4 g/mol and the molar mass of diatomic oxygen ( O₂ ) is 32 g/mol. The required ratio is _ He _ O₂ = 4 32 = 1 8 , which is 1 : 8 . Using the atomic mass of oxygen ( 16 g/mol) instead o