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Molar massMagnesium oxide
Molar mass of MgO (Magnesium oxide)
The molar mass of MgO is 40.30 g/mol.
The white powder left when magnesium ribbon burns.
Step-by-step calculation
Add up the atomic masses of every atom in the formula:
1 × 24.305 + 1 × 15.999 = 40.30 g/mol
| Element | Atoms | Atomic mass (u) | Subtotal (g/mol) | % by mass |
|---|---|---|---|---|
| Magnesium (Mg) | 1 | 24.305 | 24.305 | 60.30% |
| Oxygen (O) | 1 | 15.999 | 15.999 | 39.70% |
| Molar mass of MgO | 40.30 g/mol | |||
Moles to grams for MgO
Multiply the number of moles by 40.30 g/mol to get the mass, and divide a mass by 40.30 g/mol to get the moles.
| Amount (mol) | Mass (g) | Mass (g) | Amount (mol) |
|---|---|---|---|
| 0.1 mol | 4.03 g | 1 g | 0.0248 mol |
| 0.25 mol | 10.08 g | 5 g | 0.1241 mol |
| 0.5 mol | 20.15 g | 10 g | 0.2481 mol |
| 1 mol | 40.30 g | 50 g | 1.2406 mol |
| 2 mol | 80.61 g | 100 g | 2.4811 mol |
| 5 mol | 201.52 g | 500 g | 12.4057 mol |
Frequently asked questions
What is the molar mass of MgO?
The molar mass of MgO (magnesium oxide) is 40.30 g/mol, so one mole of magnesium oxide weighs 40.30 grams.
How do you calculate the molar mass of MgO?
Multiply each element’s atomic mass by the number of atoms in the formula and add the results: 1 × 24.305 + 1 × 15.999 = 40.30 g/mol.
What percentage of MgO is magnesium?
Magnesium makes up 60.30% of the mass of MgO.
How many grams are in one mole of MgO?
One mole of MgO has a mass of 40.30 grams, and contains 6.022 × 10²³ formula units.