The density of a gas containing carbon and oxygen at stp is 1.25g/l. what is the molar mass of this gas? what is its identity?

1.       In order to prevent the condition called “bends”. He needs to calculate the Molar Mass of the mixture of 10.0% 02, 10.0 % N2 and 80 % He.So the Answer is letter A. Calculate the molar mass of this mixture.How to calculate:Given Numbers : 10.0 % O2                               10.0% N2                               80 % HeMolar Mass = (.10 x 32g / mol.) + (.10 x 28g / mol.) + (.80 x 4g / mol.)                          => 9.2g / mol

The teacher is mostly talking about the distillation of a mixture