Determination of Formulae - Module 2.1.1 // 2.1.3 - OCR - AS Chemistry

Key definitions that ALWAYS come up, everytime!

especially on internal trial examinations!

  • Created by: kizsidhu
  • Created on: 07-02-19 10:55

Determination of Forumlae


  • Molecular Formulae
  • Empirical Forumlae
  • Relative Molecular Mass
  • Relative Formula Mass
  • Difference between Anhydrous/Hydrated
1 of 6

Molecular Formulae

Molecular Formulae =

the number of atoms of each element in a molecule

2 of 6

Empirical Formulae

Empirical Formulae =

The empirical formulae is the simplest whole number ratio of atoms of each element in a compound

3 of 6

Relative Molecular Mass

Relative Molecular Mass =

comparison of the mass of a molecule with the mass of one atom of a carbon-12 atom.

4 of 6

Relative Forumlae Mass

Relative Formulae Mass =

a comparison of the mas of a formulae unit with the mass of an atom of carbon-12.

- calculated by adding together the relative atomic masses of all the elements in the empirical formula

5 of 6

Formulae of a Hydrated Salt

Water of crystalisation = hydrated as part of crystaline structure

without water = anhydrous

6 of 6


No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Formulae resources »