Magnesium reacts with hydrochloric acid (HCl) as follows. How many milliliters of hydrogen gas are produced by the reaction 0.020 mol of magnesium with excess of hydrochloric acid at STP? Make sure to use the correct number of significant digits. 0.448 mL 0.45 mL 448 mL 450 mL

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.