Question

A sample of calcium chloride weighs 1.64g it is dissolved in water and sliver trioxonitrate(v)solution added. A precipitate of Agcl weighing 4.24g was formed .Determine the % composition and the simplest formula of calcium chloride.

Answer 1

I have rounded to th nearest 0.1 for these calculations. By the way, a correct IUPAC name for AgNO3 is silver nitrate. The name you used is not an accepted name for AgNO3.
mass AgCl = 4.24 g. Convert to mass Cl in the sample.
4.24 g AgCl x (atomic mass Cl/molar mass CaCl2) = 4.24 x (35.45/143.32) = 1.048 g Cl.
% Cl = (mass Cl/mass sample) = (1.049/1.64)*100 = 64.0%
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empirical formula
% Cl = 64
% Ca = 100 - 64 = 36
Take a 100 g sample giving you 36 Ca and 64 g Cl
mols Ca = 36/40 = 0.9
mols Cl = 64/35.5 = 1.8 and ratios are
Ca = 0.9/0.9 = 1.0
Cl = 1.8/0.9 = 2.0
empirical formula is ??