# How can percent composition be calculated?

##### 1 Answer

Jun 30, 2014

Here is an example for the compound C2HO4

You will first need to find the molar mass of the compound.

C = 2 x 12 = 24

O = 1 x 16 = 16

H = 4 x 1 = 4

Total mass = 40 amu

To find the percent composition you divide each part by the whole and multiply by 100 to convert to a %.

C = (24/44) x 100 = 54.5%

O = (16/44) x 100 = 36.4%

H = (4/44) x 100 = 9.1%

Percent composition can also be calculated using experimental data. The video below shows you how to do that type of calculation.