From Percent Composition
From Mass Data
How to Calculate Empirical Formulas
Step-by-Step Process:
- Convert to moles: Divide each element's mass (or assume 100g for percentages) by its atomic mass
- Find smallest ratio: Divide all mole values by the smallest mole value
- Round to whole numbers: If ratios are close to whole numbers, round them
- Multiply if needed: If ratios are not whole, multiply all by the same factor
- Write formula: Use the whole number ratios as subscripts
Common Multipliers:
0.5 → ×2
0.33 → ×3
0.25 → ×4
0.67 → ×3
0.75 → ×4
0.83 → ×6