Molar Mass Formula and Calculator
Molar Mass Formula and Calculator
Type any chemical formula to get its molar mass and the mass percent of each element, plus a table of common compounds.
What is molar mass?
The relative molecular mass (Mr) is the sum of the relative atomic masses of all atoms in a formula. Numerically it equals the molar mass in g/mol, the mass of one mole. Atomic masses are on the periodic table.
Molar mass formula
Molar mass of NaOH, NaCl, H2SO4 and other common compounds
| Formula | Name | Mr (g/mol) |
|---|---|---|
| NaOH | sodium hydroxide | 40.00 |
| NaCl | sodium chloride | 58.44 |
| H2SO4 | sulfuric acid | 98.08 |
| HCl | hydrochloric acid | 36.46 |
| H2O | water | 18.02 |
| CO2 | carbon dioxide | 44.01 |
| NH3 | ammonia | 17.03 |
| HNO3 | nitric acid | 63.01 |
| H3PO4 | phosphoric acid | 97.99 |
| CH3COOH | acetic acid | 60.05 |
| C2H5OH | ethanol | 46.07 |
| C6H12O6 | glucose | 180.16 |
| C12H22O11 | sucrose | 342.30 |
| CO(NH2)2 | urea | 60.06 |
| CaCO3 | calcium carbonate | 100.09 |
| Ca(OH)2 | calcium hydroxide | 74.09 |
| KOH | potassium hydroxide | 56.10 |
| KCl | potassium chloride | 74.55 |
| Na2CO3 | sodium carbonate | 105.99 |
| NaHCO3 | sodium bicarbonate | 84.01 |
| KMnO4 | potassium permanganate | 158.03 |
| K2Cr2O7 | potassium dichromate | 294.18 |
| AgNO3 | silver nitrate | 169.87 |
| CuSO4·5H2O | copper(II) sulfate pentahydrate | 249.68 |
| Na2S2O3·5H2O | sodium thiosulfate pentahydrate | 248.18 |
| Al2(SO4)3 | aluminium sulfate | 342.15 |
How to calculate molar mass
Example 1: NaOH
Na = 22.99; O = 16.00; H = 1.008.
- Mr = 22.99 + 16.00 + 1.008
Answer: 40.00 g/mol.
Example 2: H2SO4
H = 1.008; S = 32.065; O = 16.00.
- Mr = 2 × 1.008 + 32.065 + 4 × 16.00
Answer: 98.08 g/mol.
Example 3: brackets, Ca(OH)2
A number after a bracket multiplies everything inside it.
- Ca: 40.08; O: 2 × 16.00; H: 2 × 1.008
Answer: 74.09 g/mol.
Example 4: hydrate, CuSO4·5H2O
Water of crystallisation is included.
- CuSO4 = 159.61
- 5H2O = 5 × 18.02 = 90.08
Answer: 249.68 g/mol.
Frequently asked questions
What is the molar mass of NaOH?
22.99 + 16.00 + 1.008 = 40.00 g/mol, usually rounded to 40.
What is the molar mass of NaCl?
22.99 + 35.45 = 58.44 g/mol.
What is the molar mass of H2SO4?
2(1.008) + 32.065 + 4(16.00) = 98.08 g/mol.
Is relative molecular mass the same as molar mass?
The numbers are equal. Mr is dimensionless (relative to 1/12 of C-12); molar mass has units of g/mol.
Prepare solutions with analytical-grade reagents
AMI Scientific is one of the official TCI distributors in Indonesia. Reagents with lot CoA & SDS, formal quotations and tax invoices for universities and laboratories.
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