page 09 17. Iron can be produced from iron(III) oxide. 2Fe2O3(s) + 3C(s) ↓ 4Fe(s) + 3CO2(g) GFM = 159∙6 g GFM = 12·0 g GFM = 55∙8 g GFM = 44·0 g The atom economy for the production of iron is A 69∙9% B 62∙8% C 58∙2% D 32∙5%. 18. 100 cm3 of propane is mixed with 600 cm3 of oxygen and the mixture is ignited. C3H8(g) + 5O2(g) ↓ 3CO2(g) + 4H2O(ℓ) At the end of the reaction, the total volume of gas would be A 300 cm3 B 400 cm3 C 700 cm3 D 800 cm3. 19. A two-step reaction is shown below. C B step 2 step 1 A The first step gave a yield of 60% and the second step a yield of 90%. The overall yield would be A 30% B 54% C 67% D 150%. [Turn over