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Molar massHydrogen peroxide
Molar mass of H2O2 (Hydrogen peroxide)
The molar mass of H2O2 is 34.01 g/mol.
Decomposes into water and oxygen; the fuel of elephant’s toothpaste.
Step-by-step calculation
Add up the atomic masses of every atom in the formula:
2 × 1.008 + 2 × 15.999 = 34.01 g/mol
| Element | Atoms | Atomic mass (u) | Subtotal (g/mol) | % by mass |
|---|---|---|---|---|
| Hydrogen (H) | 2 | 1.008 | 2.016 | 5.93% |
| Oxygen (O) | 2 | 15.999 | 31.998 | 94.07% |
| Molar mass of H2O2 | 34.01 g/mol | |||
Moles to grams for H2O2
Multiply the number of moles by 34.01 g/mol to get the mass, and divide a mass by 34.01 g/mol to get the moles.
| Amount (mol) | Mass (g) | Mass (g) | Amount (mol) |
|---|---|---|---|
| 0.1 mol | 3.40 g | 1 g | 0.0294 mol |
| 0.25 mol | 8.50 g | 5 g | 0.1470 mol |
| 0.5 mol | 17.01 g | 10 g | 0.2940 mol |
| 1 mol | 34.01 g | 50 g | 1.4700 mol |
| 2 mol | 68.03 g | 100 g | 2.9400 mol |
| 5 mol | 170.07 g | 500 g | 14.6998 mol |
Experiments that use hydrogen peroxide
⚖️ Calculate any other formulaFrequently asked questions
What is the molar mass of H2O2?
The molar mass of H₂O₂ (hydrogen peroxide) is 34.01 g/mol, so one mole of hydrogen peroxide weighs 34.01 grams.
How do you calculate the molar mass of H2O2?
Multiply each element’s atomic mass by the number of atoms in the formula and add the results: 2 × 1.008 + 2 × 15.999 = 34.01 g/mol.
What percentage of H2O2 is oxygen?
Oxygen makes up 94.07% of the mass of H₂O₂.
How many grams are in one mole of H2O2?
One mole of H₂O₂ has a mass of 34.01 grams, and contains 6.022 × 10²³ formula units.