Practice Percent Composition in Chemistry

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

Percent composition is the percentage by mass of each element in a chemical compound.

What fraction of the compound's total weight is made up by each element inside it.

Example 1

easy
Calculate the percent composition by mass of each element in \text{H}_2\text{O}.

Example 2

medium
Calculate the percent by mass of nitrogen in ammonium nitrate (\text{NH}_4\text{NO}_3).

Example 3

easy
What is the percent composition of carbon in \text{CO}_2? (C = 12.01, O = 16.00)

Example 4

easy
What percent by mass of calcium carbonate (\text{CaCO}_3) is oxygen? (Ca = 40.08, C = 12.01, O = 16.00)