5. If 1 g of a gas occupies a volume of 300 mL at STP, what is the molecular weight of the gas?

74,67 gr/mol

Explanation:

At STP 1 mole of an ideal gas has volume of 22,4 L. Since we know the volume of the gas we can find the number of moles of the gas. (300 mL=0,3 L)

n=0,3L/22,4 L=0,01339 mol

Since we know weight of the gas as 1 g, we can find the molecular weight as;

MW=1 g/0,01339 mol = 74,67 gr/mol