The mass of an evacuated 255-mL flask is 143.187g. The mass of the flask filled with 267 torr of an unknown gas at 25 degrees Celsius is 143.289g. Calculate the molar mass of the unknown gas.

Answer 1

Use PV=nRT

This will give you the number of moles. 143.289-143.187 = 0.102 is the mass of n moles so 0.102/n is the molar mass or mass of one mole.

Answer 2

27.8

Answer 3

53562

Answer 4

27.8 is right!