Carbon is allowed to diffuse through a steel plate 8.2-mm thick. The concentrations of carbon at the two faces are 0.723 and 0.342 kg of carbon per m3 of iron, which are maintained constant. If the preexponential and activation energy are 6.5 x 10-7 m2/s and 82 kJ/mol, respectively, calculate the temperature (in K) at which the diffusion flux is 3.2 x 10-9 kg/(m2-s).