A. Fenghour, W.A. Wake ham, V. Vesovic, I.T.R. Watson, I. Millet, and E. Vogel. Phys. Chem. Ref Data 24, 1649 (1995)) have compiled an extensive table of viscosity coefficients for ammonia in the liquid and vapour phases. Deduce the effective molecular diameter of NH3 based on each of the following vapour-phase viscosity coefficients:
(a) η = 9.08 X 10-6 kg m-I S-1 at 270 K and 1.00 bar;
(b) η = 1.749 X 10-5 kg m-1 S-1 at 490 K and 10.0 bar.