A 10   g mixture of hydrogen and helium is contained in a vessel of capacity 0 . 0125   m 3 at 6 bar and 27   ° C . The mass of helium in the mixture is ..... g . (Given : R = 8 . 3 JK - 1   mol - 1 (Atomic masses of H and He are 1 u and 4 u , respectively)

Step-by-step solution

PV = n mix RT n mix = 6 × 12 . 5 0 . 083 × 300 ≈ 3 Out of total 3 moles Let mole of He = x Mole of H 2 = 3 - x Then total mass of the mixture will be = 4 x + 2 3 - x = 10 Number of moles of He gas x = 2   mol Mass of He =   number   of   moles   ×   molar   mass   =   8   g