# How do I find the percentage composition of Chlorine in CoCl_2?

Mar 16, 2016

The percent composition of chlorine in $\text{CoCl"_2}$ is 54.611%.

#### Explanation:

First determine the molar mass of cobalt chloride $\left(\text{CoCl"_2}\right)$ and the mass of chlorine in the compound. Divide the mass of chlorine by the molar mass of cobalt chloride, then multiply by 100.

Molar Mass of Cobalt Chloride

$\text{CoCl"_2} :$overbrace((1xx58.933195 "g/mol"))^color(blue)"cobalt"+overbrace((2xx35.453 "g/mol"))^color(red)"chlorine"=overbrace"129.839 g/mol"^color(purple)"cobalt chloride"

Mass of Chlorine in Cobalt Chloride

$\text{Cl"_2} :$(2xx35.453 "g/mol")="70.906 g/mol"

Percent Composition of Chlorine

%"Composition of Cl"=(70.906 cancel"g/mol")/(129.839 cancel"g/mol")xx100="54.611%