Molar Mass of MgO

Magnesium oxide. The white ash formed when magnesium ribbon burns in air.

Molar mass of MgO
40.304 g/mol
1 × 24.305 + 1 × 15.999 = 40.304

Calculation, element by element

ElementAtomsAtomic mass (g/mol)SubtotalMass %
Magnesium (Mg)124.30524.30560.30%
Oxygen (O)115.99915.99939.70%
Total40.304100%

= 0.24811 mol = 1.4942 × 1023 formula units

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MgO molar mass FAQ

What is the molar mass of magnesium oxide (MgO)?

40.304 g/mol. It is the sum of the atomic masses of every atom in the formula: 1 × 24.305 + 1 × 15.999 = 40.304 g/mol.

How many grams are in one mole of MgO?

40.304 g. Molar mass is the mass of one mole (6.022 × 10²³ formula units), so 1 mol of MgO weighs 40.304 g and 0.5 mol weighs 20.152 g.

How many moles are in 10 g of MgO?

10 g ÷ 40.304 g/mol = 0.2481 mol.

What is the percent composition of MgO?

Magnesium 60.30%, Oxygen 39.70%.

Is molecular weight the same as molar mass for MgO?

Numerically yes: the molecular (or formula) weight is 40.304 u per formula unit, and the molar mass is 40.304 g/mol.

Molar masses of other common compounds