# Weight Fraction of Iron in Pyrite

What is the weight fraction of iron Fe in pyrite?

The weight fraction of iron Fe in pyrite is 46.55%.

Pyrite, also known as fools gold, has the chemical formula FeS2. In order to calculate the weight fraction of iron Fe in pyrite, we can use the atomic masses of iron (Fe) and sulfur (S) along with the chemical formula of pyrite.

The atomic mass of Fe is 55.845 g/mol and the atomic mass of S is 32.065 g/mol. The molar mass of FeS2 can be calculated by adding the atomic masses of Fe and 2 times the atomic mass of S, which is 119.975 g/mol.

To find the weight fraction of Fe in FeS2, we can use the following formula:

Weight fraction = (atomic mass of Fe) / (molar mass of FeS2)

Plugging in the values:

Weight fraction = 55.845 / 119.975 = 0.4655

As a percentage, the weight fraction of Fe in pyrite is 46.55%.