Convert mass percent composition or mass data into empirical formulas. Use measured molar mass to determine molecular formulas. See step-by-step mole calculations, ratios, and subscript determination.
Enter the percent composition or mass data for your compound to determine its empirical and molecular formulas.
Chemical formulas tell us the composition of compounds. The empirical formula shows the simplest whole-number ratio of atoms, while the molecular formula shows the actual number of atoms in one molecule.
The simplest ratio of atoms. Example: CH₂O is the empirical formula for glucose, formaldehyde, and acetic acid.
The actual atoms per molecule. Glucose is C₆H₁₂O₆, which is 6× the empirical formula CH₂O.
Multiply each subscript in the empirical formula by n to get the molecular formula. For glucose: n = 180 ÷ 30 = 6, so CH₂O becomes C₆H₁₂O₆.
Empirical Formula: CH₂O (molar mass ≈ 30.03 g/mol)
Multiplier: n = 180.16 ÷ 30.03 ≈ 6
Molecular Formula: C₆H₁₂O₆
Hill notation is the standard way to write chemical formulas:
Educational Use Only
This tool provides a simplified educational model for determining empirical and molecular formulas. It cannot identify compounds (many isomers share the same formula) and should not be used for forensic analysis, industrial QC, pharmaceutical formulation, or regulatory submissions.
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