How many grams of oxygen are in 100.0g sucrose?

Answer 1

Ideal gas equation: pV=nRT

STP is 298K (temperature) and 1 ATM (pressure).

Use the ideal gas equation to calculate the number of moles of oxygen in 2L at STP.

Complete oxidation means that the molecule is oxidised to carbon dioxide and water.

Sucrose is C12H22O11 meaning is will be oxidised to 12 carbon dioxide and 11 water molecules (it has 12 carbon atoms and 22 hydrogen atoms in). To produce these, it will need 12x2 + 11 oxygen atoms. Since 11 atoms are already present in the sucrose, it requires an additional 24 atoms of oxygen per molecule of sucrose.

One mole is a fixed number of atoms, so the ratio will stay the same. Hence 1 mole of sucrose requires 24 moles of oxygen to oxidise it fully.

Divide the number of moles of oxygen you have calculated are present in the 2L by the number of moles of oxygen required to fully oxidise the sucrose (24). This tells you how many moles of sucrose you can fully oxidise with your oxygen.

m=n x Mr

The mass is equal to the number of moles multiplied by the relative molecular mass.

You can therefore multiply your result by the molecular mass of sucrose to find how many grams of sucrose you can fully oxidise.

Molecular mass is the addition of the atomic masses of each of the atoms in a molecule. Sucrose has a molecular mass of 342.3 grams/mole.

Answer 2

If the chemical formula of sucrose is C12H22O11 100 g of sucrose contain 176 g of oxygen.

Answer 3

5