10. A gas sample that has a mass of 6g occupies 400 mL at 504°C and a pressure of 600 mm Hg. Calculate the gas’s density at STP.

51 g/mol

Explanation:

Whenever you see molar masses in gas law questions, more often than not density will be involved. This question is no different. To solve this, however, we will first need to play with the combined ideal gas equation PV=nRT to make it work for density and molar mass. The derivation is simple but for the sake of time and space, I will skip it. Hence, just take my word for it that you will end up with the equation:

the answer is d. 74.02