The molar mass of sucrose (C12H22O11) is 342.297 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) | 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% |
| Total | 45 | 342.297 | 100.00% |
144.132 + 22.176 + 175.989 = 342.297 g/mol
Grams and moles
25 g of sucrose is 0.07304 mol, because 25 ÷ 342.297 = 0.07304.
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.
Sucrose is ordinary table sugar, a disaccharide built from one glucose unit joined to one fructose unit. It weighs 342.297 g/mol, and how that relates to its two halves is the part worth studying.
Glucose and fructose are 180.156 g/mol each. Added together they make 360.312, which is 18.015 more than sucrose actually weighs. That missing 18.015 is precisely one molar mass of water, because the bond joining the two sugars forms by eliminating a water molecule. Add the water back and the two simple sugars return, which is what digestion does and what a chemist calls hydrolysis.
The same arithmetic holds for every condensation polymer. Protein chains, starch and cellulose all weigh less than the sum of their building blocks by one water per bond, and counting those absent waters is often the fastest route to how many units a chain contains.
Carbon supplies 42.11% of the mass here, oxygen 51.41% and hydrogen 6.48%.