19.1-21. effect of a slow reaction rate on diffusion. gas a diffuses from point 1 to a catalyst surface at point 2, where it reacts as follows: 2a → b. gas b diffuses back a distance δ to point 1. derive the equation for na for a very fast reaction using mole fraction units xa1, and so on. for dab = 0.2 × 10–4m2/s, xa1 = 0.97, p = 101.32 kpa, δ = 1.30 mm, and t = 298 k, solve for na. do the same as in part (a) but for a slow first-order reaction where k1′ is the reaction velocity constant. calculate na and xa2 for part (c) where k1′=0.53×10−2m/s.

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

hurricanes form when warm, moist air from the ocean surface quickly rises into the atmosphere and forms storm clouds and rain. when the clouds are formed, heat is released which warms the cool air in the upper regions of the atmosphere so that the cycle can continue. which two phases of the water cycle are repeated in this process?

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.