Molar Mass of Sodium hydroxide

NaOH — 39.997 g/mol, worked out element by element.

Molar mass of Sodium hydroxide, NaOH

39.997 g/mol

Molecular weight 39.997 · 3 atoms per formula unit

Also known as: naoh, caustic soda, lye.

The strong base of titrations and soap-making; hygroscopic enough that weighing it accurately is genuinely hard.

How 39.997 g/mol is worked out

Mass contribution of each element
ElementAtomsAtomic massMass% of total
Sodium122.9922.99057.48%
Oxygen115.99915.99940.00%
Hydrogen11.0081.0082.52%
Total339.997100%

M = 1 × 22.990 + 1 × 15.999 + 1 × 1.008 = 39.997 g/mol

Grams to moles for Sodium hydroxide

Mass to moles conversions
MassMolesFormula units
1 g0.0250 mol1.506 × 10^22
10 g0.2500 mol1.506 × 10^23
25 g0.6250 mol3.764 × 10^23
50 g1.2501 mol7.528 × 10^23
100 g2.5002 mol1.506 × 10^24
250 g6.2505 mol3.764 × 10^24
39.997 g1 mol6.022 × 10^23

For any other amount, use the molar mass calculator, or the molarity calculator to make up a solution of a given concentration.

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Frequently Asked Questions

What is the molar mass of Sodium hydroxide?

The molar mass of Sodium hydroxide (NaOH) is 39.997 g/mol. That is the sum of the standard atomic weights of all 3 atoms in one formula unit: 1 × 22.990 + 1 × 15.999 + 1 × 1.008 = 39.997.

What is the molecular weight of Sodium hydroxide?

39.997 — the same number as the molar mass, but as a dimensionless ratio rather than in g/mol. The two terms describe the same arithmetic, so a molecular weight of 40.00 and a molar mass of 40.00 g/mol are the same answer.

How many moles are in 100 g of Sodium hydroxide?

100 ÷ 39.997 = 2.5002 mol. To convert any mass to moles, divide by the molar mass; to go the other way, multiply.

What is the percent composition of Sodium hydroxide?

By mass, Sodium hydroxide is 57.48% sodium, 40.00% oxygen, 2.52% hydrogen. Each element's share is its total mass in the formula divided by 39.997.

How many atoms are in one formula unit of Sodium hydroxide?

3: 1 sodium, 1 oxygen, 1 hydrogen. One mole contains 6.02214076 × 10²³ formula units, so a mole of Sodium hydroxide contains 3 × 6.022 × 10²³ atoms in total.