10. Diffusion (2P+2P+1P] a) b) t2 IN 0 P t1 clay cylinder AP He Figure 1: Gas diffusion through a clay cylinder. (a) Figure 2 a) shows the following experimental setup: A simple manometer is attached to the interior of a hollow cylinder made of porous clay. In the beginning, the cylinder is filled with air such that the pressure p inside equals to the pressure of the surrounding air. At time t a beaker, in which helium is floated, is imposed on the cylinder. At time t, the beaker is removed. Figure 1 b) shows the display of the manometer over time. Explain why it behaves like this. (b) Two nitrogen reservoirs with different concentrations are connected through a 5 m long circular pipe with a radius of 20 cm. The concentrations of nitrogen in the reservoirs are c = 50 kg/m3 and c3 = 30 kg/m3. At 20C nitrogen has a diffusion constant of D=3.10-5 m/s. Calculate the amount of nitrogen molecules that flow though the pipe during 10 minutes. Hint: Assume the reservoirs to be big enough, such that the concentrations are constant in good approximation. (c) Explain qualitatively how the result of b) would change if the temperature would be 100C