How much hydrogen must be added to iron (III) oxide weighing 16 grams for it to react completely?

First, we write the equation for this reaction:

Fe2O3 + 3H2 (t) = 2Fe + 3H2O

Let’s find the amount of iron (III) oxide substance:

v (Fe2O3) = m (Fe2O3) / M (Fe2O3) = 16/160 = 0.1 (mol).

According to the reaction equation, 1 mol of Fe2O3 reacts with 3 mol of H2, therefore:

v (H2) = v (Fe2O3) * 3 = 0.1 * 3 = 0.3 (mol).

Thus, the mass of hydrogen required for the reaction is:

m (H2) = v (H2) * M (H2) = 0.3 * 2 = 0.6 (g).

Answer: 0.6 g.