For oxygen ( $a = 1.36 L^{2} atm mo l^{- 2}$ , $b = 0.0318 L mo l^{- 1}$ ) the second virial coefficient is $B = b - a / RT$ . At what temperature in K (nearest integer, $R = 0.0821 L atm K^{- 1} mo l^{- 1}$ ) does $B$ equal $- 20.0 mL mo l^{- 1}$ ?

Numerical answer type, answer in K, tolerance 2.

Answer: 320 K

b - a / RT = - 0.0200

, so

a / RT = 0.0318 + 0.0200 = 0.0518

and

T = \frac{a}{0.0518 R} = \frac{1.36}{0.0518 \times 0.0821} = \frac{1.36}{0.004253} = 319.8 K

, i.e.

320 K