Percent Composition

Mathematics and science courses use percentages again and again, and chemistry is no exception. Compounds are made up of specific elements in a definite ratio. Water, for example, always has two atoms of hydrogen and one atom of oxygen. Because compounds have a set composition, it is possible to determine the percentage of the mass that each element accounts for in a compound. This is known as the percent composition. In this topic, you will explore how to calculate the percent composition of a substance in a compound.

Essential Question

• How are percentages used to describe compounds?