## anonymous 4 years ago 4. One way to change iron ore, Fe2O3, into metallic iron is to heat it together with hydrogen. Fe2O3 + 3 H2 -----------> 2 Fe + 3 H2O (a) How many moles of iron are made from 25 moles of Fe2O3? (b) How many moles of hydrogen are needed to make 30 moles of Fe?

since the reaction is balanced, 1 mole of Fe2O3 will produce 2 moles of iron. That ratio means:$25mol Fe{_2}O{_3} * (\frac{2mol Fe}{1mol Fe{_2}O{_3}})$ will make 50 moles of metallic iron. This works the same way for part (b). To make 30 moles of H2, you'll need $30mol H{_2} * (\frac{2mol Fe}{3mol H{_2}})$ 20 moles of Fe will be produced