A hydrated compound has analysis of 18.29% Ca, 32.37%CI, and49.34%H2O. What's its formula?

CaCl₂.6H₂O

Explanation:

If we suppose that the compound has a mass of 100.0 g, it will contain 18.29 grams of Ca, 32.37 grams of Cl, and 49.34 grams of water. We can convert the grams of each element to moles by dividing the number of grams by the atomic mass of each element.

No. of moles of Ca = (18.29 g) / (40.0 g/mol) = 0.457 mol.

No. of moles of Cl = (32.37 g) / (35.4 g/mol) = 0.914 mol.

No. of moles of H₂O = (49.34 g) / (18.0 g/mol) = 2.74 mol.

The no. of moles of (Ca: Cl: H₂O) is (0.457 mol: 0.914 mol: 2.74 mol). To obtain the ratio of the elements in the compound, we divide over the lowest no. of moles (0.475).

So the mole ratio of (Ca: Cl: H₂O) is (1: 2: 6).

So, the formula of the compound is CaCl₂.6H₂O.