Chemistry: According to the following reaction, how many moles of aluminum oxide will be formed upon the complete reaction of 0.694 moles iron(III) oxide with excess aluminum?

Question

iron (III) oxide (s) + aluminum (s) ———> aluminum oxide (s) + iron (s)

= moles aluminum oxide

Answer 1

This is a displacement reaction because aluminum displaces iron in iron (III) oxide to form aluminum oxide. The iron III means iron has a +3 oxidation state. The equation can be written:

2 Al(s) + Fe2O3(s) > Al2O3(s) + 2 Fe

The key to solving these problems is to look at the BALANCED chemical reaction and just look at the stoichiometric ratios.

The question is asking how many moles of aluminum oxide is formed. If we look at the chemical reaction, we see that 2 moles of aluminum and 1 mole of iron oxide are consumed to FORM 1 mole of aluminum oxide. Also the question states that aluminum is in excess which means that iron oxide is the limiting reactant. Since there is a 1:1 ratio of iron oxide to aluminum oxide, we know that .694 moles of aluminum oxide will form.