Calculate the volume of oxygen that was consumed as a result of the combustion of iron powder weighing 3, 36 g?

Let’s find the amount of the substance of the iron powder by the formula:

n = m: M.

M (Fe) = 56g / mol.

n = 3.36 g: 56 g / mol = 0.06 mol.

3Fe + 2O2 = Fe3O4.

For 3 moles of iron, there are 2 moles of oxygen. The substances are in quantitative ratios of 3: 2, or 1: 1.5.

3 mol Fe – 2 mol O2,

0.06 mol – x mol O2.

X = (0.06 × 2 mol): 3 = 0.04 mol.

V = Vn n, where Vn is the molar volume of the gas, equal to 22.4 l / mol, and n is the amount of substance.

V = 22.4 L / mol × 0.04 mol = 0.896 L.

Answer: V = 0.896 l.