2C(s)+O2(g)2CO(g) In the second step, iron(III) oxide and carbon monoxide react to form iron and carbon dioxide: Fe2O3(s)+3CO(g)2Fe(s)+3CO2(g) Suppose the yield of the first step is 94.% and the yield of the second step is 61.%. Calculate the mass of carbon required to make 7.0kg of iron. Be sure your answer has a unit symbol, if needed, and is rounded to the correct number of significant digits