diffusion constant

In air at 295 K, the molecules have five degrees of freedom each and an average mass of 4.8 × 10-26 kg, and there are 2.5 × 1025 molecules/m3. Each molecule has radius 1.9 × 10-10 m. Assume that n = 1. With this information, estimate the value of the following for diffusive processes in air:
(a) the diffusion constant,
(b) the coefficient of thermal conductivity,
(c) the coefficient of viscosity.