How much oxygen is required to react with 67.2 g of iron?

Let’s compose the equation for the reaction of the interaction of iron with oxygen:
3Fe + 2O2 = Fe3O4;

The molecular weight of iron is 56 g / mol. Let’s find the amount of substance in iron:
67.2 / 56 = 1.2 mol;

Oxygen is preceded by a coefficient that is 1.5 times less than that of iron. This means that the amount of substance in oxygen is 0.8 mol. Let’s find the volume of oxygen:
22.4 * 0.8 = 17.92 liters;

Answer: To react with iron, 17.92 liters of oxygen are required.