justyourcalculatorMolecular Weight Calculator
Molar mass and elemental composition of any chemical formula.
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Molecular Weight Calculator
Molar mass of any chemical formula
Case matters (Co is cobalt, CO is carbon monoxide). Use · , * or . for hydrates.
Converts grams to moles and molecules.
Molecular weight of CuSO4·5H2O
249.677 g/mol
- Molar mass
- 249.677 g/mol
- Atoms per formula unit
- 21
Standard atomic weights (IUPAC), rounded. Radioactive elements use the mass number of their most stable isotope.
- Copper25.45%
- Sulfur12.84%
- Oxygen57.67%
- Hydrogen4.04%
How it was calculated
- Cu: 1 × 63.546 = 63.546 S: 1 × 32.06 = 32.06 O: 9 × 15.999 = 143.991 H: 10 × 1.008 = 10.08
- Sum = 249.677 g/mol
| Element | Symbol | Atoms | Atomic mass | Total mass | Mass % |
|---|---|---|---|---|---|
| Copper | Cu | 1 | 63.546 | 63.546 | 25.451% |
| Sulfur | S | 1 | 32.06 | 32.06 | 12.841% |
| Oxygen | O | 9 | 15.999 | 143.991 | 57.671% |
| Hydrogen | H | 10 | 1.008 | 10.08 | 4.037% |
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How the molecular weight calculator works
Molecular weight (molar mass) is the sum of the atomic weights of every atom in the formula. For water, H2O = 2 × 1.008 + 15.999 = 18.015 g/mol.
Numbers after a symbol count atoms; a number after a closing parenthesis multiplies everything inside, so Ca(OH)2 has two O and two H. A hydrate like CuSO4·5H2O adds five whole water molecules.
The mass percent of each element is its total mass divided by the molar mass. One mole of a substance contains 6.022 × 10²³ formula units (Avogadro's number).
Using and checking your result
Published by JustYourCalculator. Check the units and assumptions above, and compare a known example before relying on the output. Calculations use browser arithmetic and may round displayed values.
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