Question

A compound is broken down into 34.5 g of element A, 18.2 g of element B, and 2.6 g of element C. What is the percent (by mass) of each element?

Answer 1

`A=62.3%,B=33.0%,C=4.70%`.

Explanation:

`%A` `=` `(34.5*g)/(34.5*g+18.2*g+2.6*g)xx100%=62.3%`

`%B` `=` `(18.2*g)/(34.5*g+18.2*g+2.6*g)xx100%=33.0%`

`%C` `=` `(2.6*g)/(34.5*g+18.2*g+2.6*g)xx100%=4.70%`

That is `%" element"` `=` `"Mass of element"/"Mass of compound"xx100%`

`"Mass of compound"` is clearly the SUM of the constituent elements.