Molar Mass of Phosphoric acid
H3PO4 — 97.994 g/mol, worked out element by element.
Molar mass of Phosphoric acid, H₃PO₄
97.994 g/mol
Molecular weight 97.994 · 8 atoms per formula unit
Also known as: h3po4, orthophosphoric acid.
Triprotic, so it has three ionisation steps and three pKa values — the standard buffer-problem acid.
How 97.994 g/mol is worked out
| Element | Atoms | Atomic mass | Mass | % of total |
|---|---|---|---|---|
| Oxygen | 4 | 15.999 | 63.996 | 65.31% |
| Phosphorus | 1 | 30.974 | 30.974 | 31.61% |
| Hydrogen | 3 | 1.008 | 3.024 | 3.09% |
| Total | 8 | 97.994 | 100% |
M = 4 × 15.999 + 1 × 30.974 + 3 × 1.008 = 97.994 g/mol
Grams to moles for Phosphoric acid
| Mass | Moles | Formula units |
|---|---|---|
| 1 g | 0.0102 mol | 6.145 × 10^21 |
| 10 g | 0.1020 mol | 6.145 × 10^22 |
| 25 g | 0.2551 mol | 1.536 × 10^23 |
| 50 g | 0.5102 mol | 3.073 × 10^23 |
| 100 g | 1.0205 mol | 6.145 × 10^23 |
| 250 g | 2.5512 mol | 1.536 × 10^24 |
| 97.994 g | 1 mol | 6.022 × 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 Phosphoric acid?
The molar mass of Phosphoric acid (H3PO4) is 97.994 g/mol. That is the sum of the standard atomic weights of all 8 atoms in one formula unit: 4 × 15.999 + 1 × 30.974 + 3 × 1.008 = 97.994.
What is the molecular weight of Phosphoric acid?
97.994 — 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 97.99 and a molar mass of 97.99 g/mol are the same answer.
How many moles are in 100 g of Phosphoric acid?
100 ÷ 97.994 = 1.0205 mol. To convert any mass to moles, divide by the molar mass; to go the other way, multiply.
What is the percent composition of Phosphoric acid?
By mass, Phosphoric acid is 65.31% oxygen, 31.61% phosphorus, 3.09% hydrogen. Each element's share is its total mass in the formula divided by 97.994.
How many atoms are in one formula unit of Phosphoric acid?
8: 4 oxygen, 1 phosphorus, 3 hydrogen. One mole contains 6.02214076 × 10²³ formula units, so a mole of Phosphoric acid contains 8 × 6.022 × 10²³ atoms in total.