Question

`A chemical known as pyrite is sometimes called Fool's Gold because of it's shiny color. However, it has no gold atoms in it at all! In fact, it's just iron and sulfur atoms at a molar ratio of 1 mole of iron to 2 moles of sulfur. So, using this to determine its chemical formula, what, then, is the %Fe (by mass) in Fool's Gold?

Answer 1

46.55%

Step-by-step explanation:

The molar ratio is 1 mole of iron to 2 moles of sulfur, which means that the empirical formula is FeS₂.

The mass of Fe in 1 mole of FeS₂ is 55.85 g.

The mass of S in 1 mole of FeS₂ is 2 × 32.07 g = 64.14 g.

The mass of 1 mole of FeS₂ is 55.85 g + 64.14 g = 119.99 g.

The mass percent of Fe in FeS₂ is:

`(55.85g)/(119.99g) .100\% = 46.55\%`