Calculating Percent Composition & Percent Hydrate
The percent composition can tell you what percent of an element is present in a compound. Similarly, the percent hydrate can tell you what percent of water is present in a compound containing water. In order to calculate the percent composition and the percent hydrate, you will need to use the following formulas.
When calculating the percent hydrate, keep in mind that the molar mass of the compound that goes in the denominator includes the molar mass of the water.