How do I find an element's mass contribution in a compound?

Multiply the element's atomic mass by how many atoms of it appear in the compound's formula (e.g., 2 oxygen atoms in CO₂ contribute 2×16=32 g/mol).

Percent Composition Calculator

Calculate what percentage of a compound's total molar mass comes from a specific element, a core stoichiometry calculation.

Inputs

Results

Percent Composition: 27.27%

Try an example

Formula

% Composition = (Element's Mass Contribution / Compound Molar Mass) × 100

Learn How This Works

Solution Concentration: Five Ways to Express the Same Idea

Mass percent, molality, parts per million, percent composition, and dilution factor — five different units for describing how concentrated a solution is.

Frequently Asked Questions

Related Calculators

Mass-to-Moles Calculator

Convert a mass of a substance to moles using its molar mass.

Molarity Calculator

Calculate the molarity of a solution from moles of solute and volume.

Dilution Calculator (C1V1=C2V2)

Calculate the volume needed to dilute a stock solution to a target concentration.

Ideal Gas Law Calculator

Calculate pressure, volume, moles, or temperature using PV = nRT.

Percent Yield Calculator

Calculate the percent yield of a chemical reaction.

Boyle's Law Calculator

Calculate the new pressure or volume of a gas at constant temperature.