I'm Etalie, I'm currently studying for my AS levels and will (hopefully) be posting revision entries on psychology and sociology.
I previously uploaded posts on GCSE revision. If it helps you then great! But I'm not an expert on anything AT ALL so don't rely on everything I post.
(Also, I'm not taking credit for any of the pictures or info here, it's all off google images, notes from BBC bitesize and CGP revision guides, textbooks etc)

(NB - GCSE: italics in the science subjects are things that are only in paper 2!)

Monday 12 May 2014

1 - PRINCIPLES OF CHEMISTRY 

 Elements, compounds and mixtures - 

 1 - Elements 
  • Made up of one type of atom only 
2 - Compounds 
  • Chemically bonded 
  • 2 or more different elements - bonded together 
  • eg: carbon dioxide - 1 carbon atom bonded to 2 oxygen atoms = molecule of carbon dioxide
  • Difficult to separate original elements again 
  • Properties of the compound generally very different from properties of the original elements 
  • eg: iron sulphide 
3 - Mixtures 
  • Easily separates 
  • No chemical bond between different parts of the mixture 
  • Can be separated by physical methods (eg: distillation) 
  • eg: air - mixture of gases (nitrogen, oxygen, carbon dioxide, argon), can all be separated out easily 
  • Crude oil - mixture of different length hydrocarbon molecules 
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