c8 - chemical analysis

• what is a pure substance?

  • single element or compound not mixed with any other substance
• what is a formulation?

  • a mixture of compounds in measured quantities that has been designed as a useful product
  • formulations include fuels, cleaning agents, paints, medicines, alloys, fertilisers & food
• how is Rf calculated?

  • distance moved by the spot / distance moved by solvent
• test for hydrogen

  • pop with burning splint over gas
• test for oxygen:

  • glowing splint relights
• test for carbon dioxide:

  • turns limewater cloudy / milky
• test for chlorine:

  • bleaches damp blue litmus paper white
• lithium compound flame :

  • crimson red flame
• sodium compound flame :

  • yellow flame
• potassium compound flame :

  • lilac flame
• calcium compounds flame :

  • orange red flame
• copper compound flame :

  • green flame
• A substance which is less soluble in the mobile phase will spend more time in the stationary phase, so move slower, and not travel very far up the paper.