If iron pyrite, FeS2, is not removed from coal, oxygen from the air will combine with both the iron and sulfur as coal burns. If a furnace burns in amount of coal containing 11.90g of FeS2, how much SO2 (an air pollutant) is produced?

A. 12.71
B. 3.177
C. 35.47
D. 34.95

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.