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Edexcel IGCSE Chemistry · Spec 1.31, 1.33

Empirical and Molecular Formulae from Data

Covers find empirical formulae from experimental masses, Use water-of-crystallisation data and Find molecular formulae from Mr.

Chemistry revision video

Empirical and Molecular Formulae from Data

Spec 1.31, 1.33

What you need to know

  • Find empirical formulae from experimental masses
  • Use water-of-crystallisation data
  • Find molecular formulae from Mr

Active recall

Quick check

Answer each question before opening the answer.

Why heat to constant mass?

To check that all removable water has been driven off

How is water mass found?

Initial hydrated mass minus final anhydrous mass

What is the molecular formula if the empirical formula is NO2 and Mr is 92?

N2O4

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