Molar Mass of Aluminium hydroxide

Al(OH)3 — 78.003 g/mol, worked out element by element.

Molar mass of Aluminium hydroxide, Al(OH)₃

78.003 g/mol

Molecular weight 78.003 · 7 atoms per formula unit

Also known as: al(oh)3, aluminum hydroxide.

Amphoteric: it reacts with acids and with strong bases, which is unusual enough to be examinable.

How 78.003 g/mol is worked out

Mass contribution of each element
ElementAtomsAtomic massMass% of total
Oxygen315.99947.99761.53%
Aluminum126.98226.98234.59%
Hydrogen31.0083.0243.88%
Total778.003100%

M = 3 × 15.999 + 1 × 26.982 + 3 × 1.008 = 78.003 g/mol

Grams to moles for Aluminium hydroxide

Mass to moles conversions
MassMolesFormula units
1 g0.0128 mol7.720 × 10^21
10 g0.1282 mol7.720 × 10^22
25 g0.3205 mol1.930 × 10^23
50 g0.6410 mol3.860 × 10^23
100 g1.2820 mol7.720 × 10^23
250 g3.2050 mol1.930 × 10^24
78.003 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 Aluminium hydroxide?

The molar mass of Aluminium hydroxide (Al(OH)3) is 78.003 g/mol. That is the sum of the standard atomic weights of all 7 atoms in one formula unit: 3 × 15.999 + 1 × 26.982 + 3 × 1.008 = 78.003.

What is the molecular weight of Aluminium hydroxide?

78.003 — 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 78.00 and a molar mass of 78.00 g/mol are the same answer.

How many moles are in 100 g of Aluminium hydroxide?

100 ÷ 78.003 = 1.2820 mol. To convert any mass to moles, divide by the molar mass; to go the other way, multiply.

What is the percent composition of Aluminium hydroxide?

By mass, Aluminium hydroxide is 61.53% oxygen, 34.59% aluminum, 3.88% hydrogen. Each element's share is its total mass in the formula divided by 78.003.

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

7: 3 oxygen, 1 aluminum, 3 hydrogen. One mole contains 6.02214076 × 10²³ formula units, so a mole of Aluminium hydroxide contains 7 × 6.022 × 10²³ atoms in total.