# A sample of a compound analyzed in a chemistry laboratory consists of 5.34 g of carbon, 0.42 g of hydrogen, and 47.08 g of chlorine. What is the percent composition of this compound?

Aug 7, 2016

$\text{% element by mass}$ $=$ "Mass of element"/"Mass of compound"xx100%
And thus %C $=$ (5.34*g)/(5.34*g+0.42*g+47.08*g)xx100% $=$ 10.1%
I leave it to you to find %H and %Cl. And of course the percentages must sum to 100%. Why?