Calculate the percentage by mass of each element in a compound.
Percent composition converts a formula into the mass fractions you would measure by analysis. The defaults give glucose, which is 40.0% carbon, 6.7% hydrogen and 53.3% oxygen. Comparing calculated percent composition with elemental analysis is the standard way to confirm a proposed formula.
Percent Composition
Element % = (atoms × atomic mass) ÷ molar mass × 100
Element % = (atoms × atomic mass) ÷ molar mass × 100 Percent composition converts a formula into the mass fractions you would measure by analysis. The defaults give glucose, which is 40.0% carbon, 6.7% hydrogen and 53.3% oxygen.
Comparing calculated percent composition with elemental analysis is the standard way to confirm a proposed formula.
This calculator takes 3 inputs: Total mass of element 1 in the formula, Total mass of element 2 in the formula, Total mass of element 3 in the formula. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.