A differential nitrogen pressure exists across a 2-mm-thick steel furnace wall. After some time, steady-state diffusion of the nitrogen is established across the wall. Given that the nitrogen concentration on the high-pressure surface of the wall is 5 kg/m3 and on the low-pressure surface is 0.2 kg/m3, calculate the flow of nitrogen through the wall (in kg/m2 xh) if the diffusion coefficient for nitrogen in this steel is 1.0 x10^-10m2/s at the furnace operating temperature.