Answers

2016-03-15T22:22:17+05:30
Calcium Chloride is CaCl2 

You need to get the MW (molecular weight) 
Ca = 1 x 40.08 = 40.08 
Cl = 2 x 35.453 = 70.906 
= 110.986 g/mol 

Ca = (40.08 / 110.986) x 100 = 36 % 
Cl = (70.906 / 110.986) x 100 = 64% 

64% is the percent by mass of Cl
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