(1) Consider a low-pressure chemical vapor deposition diffusion reactor to lay a thin film of the semiconductor gallium, Ga, onto a silicon wafer surface. Gallium metal is not volatile, but trimethyl gallium (TMG, Ga(CH3)3, 114.72 g/g mol) is volatile. In the presence of H2 gas at high temperature, TMG will decompose to solid Ga on a surface by the following reaction: Ga(CH3)3 (g) +3/2 H (g) Ga (s) +3 CH4 (g). At 700 C, this surface reaction is diffusion limited. (a) Develop an integral model to predict the flux of TMG to the wafer surface. (b) What would be the simplified model of (a) if the reactants are dilute. (2) A porous cylinder of 2.4 cm in diameter and 80 cm long is saturated with an alcohol. The void space in the solid contains sufficient pores so that molecular diffusion can take place through the liquid in the passage. The cylinder is dropped into a large, well agitated reservoir of pure water. The agitation maintains the concentration of 1wt% alcohol at the surface of the cylinder. If the concentration at the center of the cylinder drops from 25wt% to 15wt% in 10 h, determine the concentration in weight percent at the center after 15 h.