a sample bulb contained 0.712g of H2(g) at a certain temperature and pressure. At the same temperature and pressure, the bulb can hold 13.0g of an unknown gas. What is the molar mass of the unknown gas?

Answer 1

0.712 g of H2 is 0.353 moles

The bulb will hold 0.353 moles of any gas at the same p and T.

If 13.0 g = 0.353 moles, one mole has a mass of 36.8 g, and so that is the molar mass of the unknown gas