How do I calculate the molar volume and pressure correction terms in the van der Waals equation of state for "CO"_2CO2 if the density of "CO"_2CO2 at a certain temperature is "4.4 g/L"4.4 g/L, while a = "3.6 L"^2cdot"atm/mol"^2a=3.6 L2⋅atm/mol2 and b = "0.04 L/mol"b=0.04 L/mol?
1 Answer
Dec 7, 2017
The van der Waals (vdW) volume correction and pressure correction terms in
P = (RT)/(barV - b) - a/(barV^2)P=RT¯¯¯V−b−a¯¯¯V2
are:
barV_"corr" = barV - b¯¯¯Vcorr=¯¯¯V−b
P_"corr" = a/(barV^2)Pcorr=a¯¯¯V2 where
barV = V/n¯¯¯V=Vn is the molar volume,aa is the vdW term for intermolecular forces, andbb is the vdW term for excluded volume of a non-point-mass particle.
Therefore:
barV_"corr" = "1 L"/(4.4 cancel"g" cdot "1 mol"/(44.01 cancel("g CO"_2))) - "0.04 L"/"mol"
= ul"9.96 L/mol"
P_"corr" = (3.6 cancel("L"^2)cdot"atm"/cancel("mol"^2))/([1 cancel"L"//4.4 cancel"g" cdot cancel"1 mol"/(44.01 cancel("g CO"_2))]^2)
= ul"0.360 atm"