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

FORMULAE DISCUSSED IN THIS RESOURCE

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

Molecular Formulae =

the number of atoms of each element in a molecule

Empirical Formulae =

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

Relative Molecular Mass =

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

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

Water of crystalisation = hydrated as part of crystaline structure

without water = anhydrous