The reduction of iron(iii) oxide (fe2o3) to pure iron during the first step of steelmaking, 2fe2o3(s)→ 4fe(s)+ 3o2(g) is driven by the high-temperature combustion of coke, a purified form of coal: c(s)+ o2(g)→ co2(g) suppose at the temperature of a blast furnace the gibbs free energies of formation δgf of co2 and fe2o3 are −429./kjmol and −835./kjmol, respectively. calculate the minimum mass of coke needed to produce 6400.kg of pure iron. round your answer to 2 significant digits.