Q1 Agar slab (15 pt] You are working in a biotech lab. And you immerse a long slab of solid agar gel which contains urea, suddenly in pure water. The agar gel is 8 mm thick, has a temperature of 25 C and has an initial uniform concentration of urea of 0.25 kmol/m3. The mass diffusivity of urea in this particular agar is 4.72. 10-10 m2/s. You will neglect the surface resistance. a.) Make a useful and relevant schematic drawing of the above situation. Write down all known relevant parameters in the right place of the schematic and show the direction of the mass transfer with arrows. [4 pt] b.) Explain why in the described situation dynamic mass transfer is taking place. [2 pt] c.) Calculate the concentration of urea in the center line of the slab after 7 hours. Use the Known, Find, Assumptions (minimum of two) and Analysis approach. [9 points]