Given,
Initial pressure (Pi)=722 mm Final pressure (Pf)=760 mm
Initial temperature (Ti)=(107+273) K=380 K Final temperature (Tf)=100 K
Initial density (di)=1 g /cm3Final density (df)=?
We know, PM=dRT
Where, M=Molar mass
Since M is same here, thus we can write
diTiRPi=dfTfRPf
⇒df=(pfpi)(TiTf)di
=(760722)(380100)×1 g/cm3
=4 g/cm3