Imagine that you have been assigned 5 substances for which you will observe the rate of diffusion. The only information that you have about your materials is the molecular weight of each substance, listed below: Substance #1: 212 mg Substance #2: 1918 mg Substance #3: 50 mg Substance #4: 4 mg Substance #5: 700 mg If the substances are allowed to diffuse for one hour, what can you predict about the rate of diffusion?

the cold front replaces the warmer air at the ground level changing the wind to be breezy and denser.there is also an immediate drop in the temperature.

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.