Question

Fluorite, a mineral of calcium, is a compound of the metal with fluorine. Analysis shows that a 2.76g sample of Fluorite contains 1.42g calcium. Calculate the mass fraction of calcium and fluorine in Fluorite.

Answer 1

Answer:

Mass fraction for Ca is 0.52

Mass fraction for F is 0.48

Explanation:

Molecular formula for fluorite is CaF₂

Molar mass: 78.08 g/mol

1 mol of CaF₂ has 1 mol of Ca and 2 moles of F

1 mol of Ca = 40.08 g

2 mol of F = 38 g

We verify the relation by rules of three:

78.08 g of CaF₂ have 40.08 g of Ca

2.76 g of CaF₂ must have (2.76 g . 40.08g ) / 78.08 g = 1.42 g

So, 78.08 g of CaF₂  have 38 g of F

2.76 g of CaF₂  must have (2.76 . 38 ) / 78.08 g = 1.34 g

Mass fraction = Grams of Ca / Total grams or Grams of F / Total grams

1.42 g / 2.76 g = 0.52

1.34 g / 2.76 g = 0.48