For $CO X_{2}$ the van der Waals constant $b = 0.0427 L mo l^{- 1}$ . The critical volume predicted by the van der Waals equation, in $mL mo l^{- 1}$ (one decimal), is

Numerical answer type, answer in mL/mol, tolerance 0.2.

Answer: 128.1 mL/mol

V_{c} = 3 b = 3 \times 0.0427 = 0.1281 L mo l^{- 1} = 128.1 mL mo l^{- 1}

. The experimental value is about

94 mL mo l^{- 1}

, so the van der Waals prediction is somewhat high.