Percent Composition Calculator
Calculate percent composition by mass of elements in a chemical compound. Free online calculator with step-by-step results and visual charts.
About This Calculator
The Percent Composition Calculator determines the mass percentage of each element in a binary compound. Enter the mass of each element to instantly get the percent composition by mass.
Percent composition is a fundamental concept in chemistry used to determine the elemental makeup of compounds, verify purity, and derive empirical formulas. The calculation divides each element's mass by the total mass and multiplies by 100%.
Frequently Asked Questions
What is percent composition in chemistry?
Percent composition is the percentage by mass of each element in a compound. It is calculated as (mass of element / total mass of compound) x 100%.
How do you calculate percent composition?
Divide the mass of each element by the total mass of the compound and multiply by 100. For example, in water H2O, hydrogen is 11.19% and oxygen 88.81% by mass.
What is the percent composition of water?
Water (H2O): hydrogen = 11.19% by mass, oxygen = 88.81% by mass. Calculated from H (2 x 1.008 = 2.016 g/mol) and O (16.00 g/mol) out of total 18.016 g/mol.
How is percent composition used to find empirical formulas?
Convert each element's mass percentage to grams (assuming 100 g sample). Divide each mass by the element's atomic mass to get moles. Divide all mole values by the smallest to get the simplest whole-number ratio.
Can percent composition confirm compound purity?
Yes, comparing experimental percent composition to theoretical values helps assess purity. Analytical chemistry uses this for quality control in pharmaceutical and industrial manufacturing.