Calculate the empirical formula of a chemical compound from elemental mass percentages or gram amounts. Finds the simplest whole-number ratio of atoms.
Empirical Formula
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Total Percentage
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Calculation Status
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An empirical formula represents the simplest whole-number ratio of atoms in a compound. It shows the relative number of atoms of each element present, but not the actual number of atoms.
The empirical formula shows the simplest ratio of atoms, while the molecular formula shows the actual number of atoms in a molecule. For example, glucose has molecular formula C₆H₁₂O₆ but empirical formula CH₂O.
Ethanol (C₂H₆O) has the empirical formula C₂H₆O, which is already in its simplest form since the ratio 2:6:1 cannot be reduced further while maintaining whole numbers.
No, a compound can have only one empirical formula. However, multiple compounds can share the same empirical formula but have different molecular formulas.
Ideally, mass percentages should total 100%. Small deviations (±2%) are acceptable due to experimental error, but larger differences may indicate missing elements or measurement errors.
To convert mass in grams to percentage, divide each element's mass by the total mass of the sample, then multiply by 100. For example, if you have 12g C and 4g H in a 16g sample: C = (12/16)×100 = 75%, H = (4/16)×100 = 25%.