An evacuated glass vessel weighs \( 40.0 \, \text{g} \) when empty, \( 135.0 \, \text{g} \) when filled with a liquid of density \( 0.95 \, \text{mL}^{-1} \) and \( 40.5 \, \text{g} \) when filled with an ideal gas at \( 0.82 \, \text{atm} \) at \( 250 \, \text{K} \). The molar mass of the gas in \( \text{g mol}^{-1} \) is: (Given: \( R = 0.082 \, \text{L atm K}^{-1} \, \text{mol}^{-1} \))
