The molar mass of glucose (C6H12O6) is 180.156 g/mol.
Case matters: CO is carbon monoxide, Co is
cobalt. Brackets and hydrates are fine — try
or
.
| Element | Atoms | Atomic mass | Mass contributed | Percent |
|---|---|---|---|---|
| Carbon (C) | 6 | 12.011 | 72.066 | 40.00% |
| Hydrogen (H) | 12 | 1.0080 | 12.096 | 6.72% |
| Oxygen (O) | 6 | 15.999 | 95.994 | 53.28% |
| Total | 24 | 180.156 | 100.00% |
72.066 + 12.096 + 95.994 = 180.156 g/mol
Grams and moles
25 g of glucose is 0.1388 mol, because 25 ÷ 180.156 = 0.1388.
These elements have no single atomic weight. Their isotopic mix varies slightly depending on where on Earth the sample came from, so the figure used here is the conventional value IUPAC publishes for when one number is needed: carbon is 12.011, and really lies between 12.0096 and 12.0116; hydrogen is 1.0080, and really lies between 1.00784 and 1.00811; oxygen is 15.999, and really lies between 15.99903 and 15.99977.
Glucose is the sugar the bloodstream carries and the one cellular respiration burns, so it appears in biology courses as often as in chemistry ones. Its molar mass of 180.156 g/mol breaks down as 72.066 from carbon, 12.096 from hydrogen and 95.994 from oxygen.
Two things about that number are worth knowing. Fructose and galactose have exactly the same molar mass, because they have exactly the same formula. They are structural isomers, identical atoms arranged differently, and no mass measurement will ever separate them. That is why sugar chemistry leans on optical rotation and enzyme specificity instead of weighing.
The second is that glucose has the same percent composition as acetic acid: 40.00% carbon, 6.72% hydrogen, 53.28% oxygen. Both reduce to the empirical formula CH2O. Percent composition alone cannot tell a molecule apart from one six times its size, which is exactly why an empirical formula has to be paired with a measured molar mass before it becomes a molecular formula.