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C2 3.3 Percentages and formulae

C2 3.3 Percentages and formulae

Author: Gemma Boyson
  • How can we calculate the percentage of an element in a compound from its formula?
  • How can we calculate the empirical formula of a compound from its percentage composition?
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How to calculate percentage mass

Source: Fuse School

Calculating Empirical Formulae

This video goes over how to calculate empirical formulae with two exam questions as examples.

Source: G Boyson

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Percentage by mass

Source: myGCSEscience

The myGCSEscience video below...

In this video, the man explains how to calculate empirical formulae in the exact same way that I do it. He explains it very well, very clearly.

I strongly suggest you grab some note paper and your calculator and write it down as he goes through it. Plug the numbers into your calculator to prove to yourself that this works.

The only way to learn this is to PRACTICE it! over and over and over again...

Empirical Formulae

Source: myGCSEscience

OPTIONAL: Stoichiometry

Source: Crash Course

OPTIONAL: Molecular and Empirical Formula

Source: Khan Academy