Molar mass of H2 (Hydrogen)
The molar mass of H2 is 2.02 g/mol.
The lightest gas; it burns with a squeaky pop.
Step-by-step calculation
Add up the atomic masses of every atom in the formula:
2 × 1.008 = 2.02 g/mol
| Element | Atoms | Atomic mass (u) | Subtotal (g/mol) | % by mass |
|---|---|---|---|---|
| Hydrogen (H) | 2 | 1.008 | 2.016 | 100.00% |
| Molar mass of H2 | 2.02 g/mol | |||
Moles to grams for H2
Multiply the number of moles by 2.02 g/mol to get the mass, and divide a mass by 2.02 g/mol to get the moles.
| Amount (mol) | Mass (g) | Mass (g) | Amount (mol) |
|---|---|---|---|
| 0.1 mol | 0.20 g | 1 g | 0.4960 mol |
| 0.25 mol | 0.50 g | 5 g | 2.4802 mol |
| 0.5 mol | 1.01 g | 10 g | 4.9603 mol |
| 1 mol | 2.02 g | 50 g | 24.8016 mol |
| 2 mol | 4.03 g | 100 g | 49.6032 mol |
| 5 mol | 10.08 g | 500 g | 248.0159 mol |
Experiments that use hydrogen
🐘 Elephant's toothpaste
Iodide-catalysed decomposition of 30% hydrogen peroxide produces a towering, steaming foam.
⚡ Electrolysis of water
Split water in a Hofmann voltameter: twice as much hydrogen as oxygen.
🧂 Electrolysis of brine
Chlorine at the anode, hydrogen at the cathode, sodium hydroxide left behind.
💥 Sodium & potassium in water
Alkali metals skate across water, fizzing; the indicator turns pink.
Frequently asked questions
What is the molar mass of H2?
The molar mass of H₂ (hydrogen) is 2.02 g/mol, so one mole of hydrogen weighs 2.02 grams.
How do you calculate the molar mass of H2?
Multiply each element’s atomic mass by the number of atoms in the formula and add the results: 2 × 1.008 = 2.02 g/mol.
What percentage of H2 is hydrogen?
Hydrogen makes up 100.00% of the mass of H₂.
How many grams are in one mole of H2?
One mole of H₂ has a mass of 2.02 grams, and contains 6.022 × 10²³ formula units.