To find out how many moles of Fe2O3 can be made from a 1.25-mol sample of iron, we need to use the stoichiometric coefficients from the balanced equation.
According to the balanced equation, the ratio of Fe to Fe2O3 is 4:2, or simplified, 2:1. This means that for every 2 moles of Fe, we can expect to get 1 mole of Fe2O3.
Given that we have a 1.25-mol sample of iron, we can use this ratio to determine the moles of Fe2O3.
Since the ratio is 2:1, we divide the moles of Fe by 2 to get the moles of Fe2O3.
1.25 mol Fe / 2 = 0.625 mol Fe2O3
Therefore, with a 1.25-mol sample of iron, we can produce 0.625 moles of Fe2O3.