Molar Mass from Chemical Formula Calculator
Need a compound’s molar mass fast? Enter its chemical formula — including parentheses and hydrates like CuSO4·5H2O — and get an instant, element-by-element breakdown and total in g/mol.
Background
This calculator computes the molar mass of a compound directly from its chemical formula. It parses element symbols and subscripts (including parentheses and hydrates like CuSO4·5H2O), multiplies each element’s atomic weight by its count, and sums the total. Use this to check homework, prep labs, or build intuition for stoichiometry.
How to use the molar mass calculator
1) Type a valid chemical formula (case sensitive for element symbols).
2) Parentheses and nested groups are supported (e.g., Al2(SO4)3).
3) Hydrates with a dot are supported (· or .), e.g., CuSO4·5H2O.
4) Click Calculate Molar Mass to see the breakdown and total.
Key Points
- Atomic weights are IUPAC-typical values (to 3–4 sig figs).
- For coursework, use the same atomic weights your class/teacher provides.
- This tool computes the sum: Σ (countelement × atomic weight).
Formula & Equation Used
Total molar mass (M) is:
- n(element): number of atoms of that element in the formula unit
- AW(element): atomic weight (g/mol)
Example Problems & Step-by-Step Solutions
Example 1:
Find the molar mass of glucose, C6H12O6.
- C: 12.011 × 6 = 72.066 g/mol
- H: 1.008 × 12 = 12.096 g/mol
- O: 15.999 × 6 = 95.994 g/mol
- Total = 72.066 + 12.096 + 95.994 = 180.156 g/mol ≈ 180.16 g/mol
Example 2:
Find the molar mass of calcium hydroxide, Ca(OH)2.
- Ca: 40.078 × 1 = 40.078 g/mol
- O: 15.999 × 2 = 31.998 g/mol
- H: 1.008 × 2 = 2.016 g/mol
- Total = 40.078 + 31.998 + 2.016 = 74.092 g/mol ≈ 74.09 g/mol
Frequently Asked Questions
Q: Do hydrates work (e.g., CuSO4·5H2O)?
Yes—use a dot (·) or period (.) between parts. The calculator multiplies each hydrate part correctly.
Q: Are parentheses supported?
Yes. Parentheses and nesting are supported: Al2(SO4)3, Ca(OH)2, etc.
Q: Which atomic weights are used?
Standard IUPAC-style atomic weights (typical table values). For strict grading, match your course’s table.
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