A home owner uses 4.00 × 10^3 m^3 of methane ( CH_4) gas, (assume CH_4 is an ideal gas) in a year to heat his home. Under the pressure of 1.0 atm and…

A home owner uses $\displaystyle 4.00 \times 10^3 \mathrm{~m}^3$ of methane $\displaystyle \left(\mathrm{CH}_4\right)$ gas, (assume $\displaystyle \mathrm{CH}_4$ is an ideal gas) in a year to heat his home. Under the pressure of $\displaystyle 1.0$ atm and $\displaystyle 300$ K , mass of gas used is $\displaystyle x \times 10^5 \mathrm{~g}$. The value of $\displaystyle x$ is \_\_\_\_. (Nearest integer) (Given $\displaystyle \mathrm{R}=0.083 \mathrm{~L} \mathrm{~atm} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}$ )