Question

In the lab you find four bags; each contains 5.00 g of a different gas at STP. The gases are O2, CH4, CO2, and He. Which bag has the largest volume?

Answer 1

lesser the molar mass of the gas higher the no. of moles included in a certain mass sample. ie at STP more volume is required for the gas having less molar mass.

He has the smallest molar mass.

Therefore bag of He is the biggest.