Respuesta :
The molar mass of the mixture is the summation of the molar mass of a compound in a mixture to its respective molar mass. In this case, 0.10*32 g/mol added to 0.10*28 g/mol and 0.80 *4 g/mol is equal to 9.2 g/mol. The density ratio of the gas to pure oxygen is the ratio of the molar mass between the two, hence 9.2/32 is 0.2875.
molar mass = 0.1 * MO2 + 0.1 * MN2 + 0.8 * MHe
molar mass = 9.2 g / mo
molar mass = 9.2 g / mo
For the second part, use PV=nRT, arranged for density. The density ratio of the gas to pure oxygen is the ratio of the molar mass between the two
ratio = PM / RT
ratio = 9.2 / 32
ratio = 0.2875