A substance contains 36.1 percent calcium and 63.9 percent chlorine by weight. what is the empirical formula of thegiven compound?

Assume 100 g of the compound is present. This converts the percentages into mass. Then, calculate moles of each element:

Ca - - - > 36.1 g / 40.08 g/mol = 0.9007

Cl - - - > 63.9 g / 35.453 g/mol = 1.802

Next, look for the lowest whole-number ratio. We do this by dividing by the smallest value:

Ca - - - > 0.9007 / 0.9007 = 1

Cl - - - > 1.802 / 0.9007 = 2

The empirical formula is CaCl2