A78.0-g sample of an unknown compound contains 12.4 g of hydrogen. What is the percent by mass of hydrogen in the compound?

1 Answer
Sep 14, 2016

#"%hydrogen"# #=# #(12.4*g)/(78.0*g)xx100%# #~=15%#

Explanation:

So all we have done is take the quotient:

#"Mass of hydrogen"/"Mass of stuff"xx100%#