On this page
Understanding Percent Composition by Mass
Formula
Percent composition by mass tells you what fraction of a compound's total mass comes from each element. It is calculated by dividing the total mass of each element in one mole of the compound by the molar mass of the compound, then multiplying by 100.
This concept is fundamental in analytical chemistry for identifying unknown compounds, verifying purity, and determining empirical formulas from experimental data.
Common use cases:
- Identifying unknown compounds
- Verifying compound purity
- Nutritional analysis of minerals
Frequently Asked Questions
Was this calculator helpful?
People Also Use
pH Calculator
Calculate pH, pOH, and hydrogen ion concentration from any given value using logarithmic acid-base formulas.
Molarity Calculator
Calculate molarity (molar concentration) from solute mass, molar mass, and solution volume with this free chemistry tool.
Dilution Calculator
Calculate dilution volumes and concentrations using the C1V1 = C2V2 equation for laboratory solution preparation.
Ideal Gas Law
Solve the ideal gas law equation PV = nRT for pressure, volume, temperature, or moles with unit conversions.
Mole Calculator
Convert between moles, grams, and number of particles using molar mass and Avogadro's number.
Molecular Weight
Calculate the molecular weight and elemental composition of any chemical compound from its formula.
Solution Concentration
Calculate solution concentration in mass percent, ppm, and molality from solute and solvent amounts.
Boiling Point Elevation
Calculate the boiling point elevation of a solution using the ebullioscopic constant, molality, and van't Hoff factor.