Molar MassMolar mass of sucrose (C12H22O11)
The molar mass of sucrose, C12H22O11, is 342.30 g/mol. One mole of it, which is 6.022 × 1023 molecules, has a mass of 342.30 grams.
342.30 g/mol
12 × 12.011 + 22 × 1.0080 + 11 × 15.999 = 342.297 · 45 atoms in the formula · also called table sugar, cane sugar
About sucrose
Sucrose is ordinary sugar from sugar cane or sugar beet. A molecule is one glucose joined to one fructose with the loss of one water molecule, which is why its formula is not simply double that of glucose.
Other names: table sugar, cane sugar.
The working
The formula C12H22O11 has 12 carbon atoms, 22 hydrogen atoms and 11 oxygen atoms, 45 atoms in all. Multiply each count by the atomic weight of the element and add:
| Element | Atoms | Atomic weight | Total | Share by mass |
|---|---|---|---|---|
| Carbon (C) | 12 | 12.011 | 144.132 | 42.11% |
| Hydrogen (H) | 22 | 1.0080 | 22.176 | 6.48% |
| Oxygen (O) | 11 | 15.999 | 175.989 | 51.41% |
12 × 12.011 + 22 × 1.0080 + 11 × 15.999 = 342.297 g/mol
With the rounded atomic masses used in many school books (C = 12, H = 1, O = 16) the answer is 342 g/mol. The difference from 342.30 is too small to matter in most school sums.
Percentage composition
By mass, C12H22O11 is 42.11% carbon, 6.48% hydrogen and 51.41% oxygen. The largest share comes from oxygen. In a 100 g sample there are 42.1 g of carbon, 6.5 g of hydrogen and 51.4 g of oxygen.
Notice that hydrogen has more atoms in the formula (22) than oxygen (11), yet gives a smaller share of the mass. Percentage by mass depends on how heavy each atom is, not only on how many there are.
Worked examples
Grams to moles. How many moles are in 50 g of C12H22O11? Divide the mass by the molar mass: 50 ÷ 342.30 = 0.1461 mol.
Moles to grams. What is the mass of 0.4 mol of C12H22O11? Multiply: 0.4 × 342.30 = 136.9 g.
Counting particles. 50 g contains 0.1461 mol × 6.022 × 1023 = 8.797 × 1022 molecules, and 3.958 × 1024 atoms in all.
Quick conversion tables
| Amount | Mass |
|---|---|
| 0.1 mol | 34.23 g |
| 0.5 mol | 171.1 g |
| 1 mol | 342.3 g |
| 2 mol | 684.6 g |
| 5 mol | 1711 g |
| Mass | Moles |
|---|---|
| 1 g | 0.002921 mol |
| 10 g | 0.02921 mol |
| 100 g | 0.2921 mol |
| 1 kg | 2.921 mol |
For other amounts use the grams and moles converter.
Questions people ask
What is the molar mass of C12H22O11?
The molar mass of sucrose (C12H22O11) is 342.30 g/mol, or 342.297 g/mol before rounding, using IUPAC abridged atomic weights.
How many moles are in 100 g of C12H22O11?
100 ÷ 342.30 = 0.2921 mol.
What is the mass of one molecule of C12H22O11?
Divide the molar mass by the Avogadro constant: 342.30 ÷ 6.022 × 1023 = 5.684 × 10-22 g.
What is the percentage of oxygen in C12H22O11?
Oxygen makes up 51.41% of the mass of C12H22O11: 11 × 15.999 ÷ 342.297 × 100.
Which values? This site uses the abridged standard atomic weights published by IUPAC (CIAAW), read on 12 November 2026. Your textbook or question paper may round them differently, for example H = 1 and O = 16, so its answer can differ slightly. In an exam, use the values the paper gives.