Calculate the density, g/cm3, of propane C3H8 at 97.0oC and 838 torr.?

molar m = (density * R*T)/P (can be derived from the ideal gas law). So, propane has a molar m of 44 g/mol, R is the ideal gas constant which is 0.08206 L*atm/K*mol, T is given, convert to Kelvin (273 + 97), and Pressure needs to be converted to atm so that units cancel. (838/760 since 1 atm = 760 torr). Rearranging your equation to isolate your unknown (density) you have d = (MM * P) /(R*T). Plugging all this in, you get 1.60 g/L. You need your answer in g/cm3 so you convert L to mL then mL to cm3 (1000 mL = 1 L, and 1 mL = 1cm3). 1.60 e-3 is the final answer.