Calculation of the density of methane by use of the PENG-ROBINSON equation o state. 2.0kg methane ( MC1=16kgk/mole is hold at temperature of 305.12K an at pressure of 9.26MPa. =nVm=VM The critical data and the acentric factor of methane are known as Tc=190.6K,ac=0.457235pc(RTc)2,b=0.07796pcRTc,=0.0115.p=VbRTV(V+b)+b(Vb)a,Vc3(pRTb)V2+(bap2bRT3b2)V(bpapRTbb2)=0.ac=0.457235pc(RTc)2,a=ac,=Tr0.5b=0.07796pcRTc