Determine the density of methane (CH4) in g/L at 21.9oC and 0.9 atm

Answer 1

The general formula of PV = nRT can be altered to PVM = gRT and further to
PM = dRT
where P is pressure in atm, M is molar mass, d is density in g/L, R is 0.08206 and T is temperature in kelvin.