So, you know the volume your gas occupies, and the temperature and pressure at which it is kept. Because you were given its molar mass, you can solve for its mass by using the ideal gas law equation,
SInce you know the weight of 1 mole, determining the number of moles will help figure out the weight of the gas.
SIDE NOTE Do not forget to convert mmHg and degrees Celsius to atm and pressure, respectively, if you want to use the value R = 0.082, since it's expressed in atm L/mol K.
This means that its mass in kilograms will be
Rounded to three sig figs, the answer will be