Molar Mass & Empirical Formula Calculator
Type a formula to get its molar mass and percent composition, or switch modes to work backward from percents or grams to an empirical and molecular formula.
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Use capitals for element symbols. Parentheses, brackets, and hydrate dots (· or * or .) are supported.
Molar mass
342.13 g/mol
| Element | Atoms | Atomic mass | Subtotal (g/mol) | % by mass |
|---|---|---|---|---|
| Aluminum (Al) | 2 | 26.982 | 2 × 26.982 = 53.964 | 15.77% |
| Sulfur (S) | 3 | 32.06 | 3 × 32.06 = 96.180 | 28.11% |
| Oxygen (O) | 12 | 15.999 | 12 × 15.999 = 191.988 | 56.12% |