Calculate the molar volume of ammonia at \(350 \mathrm{~K}\) and 100 bar using van der Waals equation of state, given that \(a=0.4233 \mathrm{Nm}^{4} / \mathrm{mol}^{2}\) and \(b=3.73 \times 10^{-5} \mathrm{~m}^{3} / \mathrm{mol}\).