C12

• Rf = distance moved by substance / distance moved by solvent
• Pure substance is made up of just one element or compound
• Test for water is that it will turn anhydrous copper sulfate blue.
• A mixture changes state at a range of temperatures
• Impurities lower the melting point and raises it bowling point
• Mobile phase is the solvent
• stationary phase is the paper
• The more soluble a substance the further travel up the paper
• Lithium - crimson
• Sodium - yellow
• Potassium - lilac
• Calcium - orange
• Copper - green
• Aluminium ions are present when excess sodium hydroxide dissolves
• Copper forms a blue precipitate
• Iron (II) ions forms a green precipitate
• Iron (III) forms a brown precipitate
• You can identify halides by adding nitric acid, the a Silver nitrate solution
• Chloride - white precipitate
• Bromide - cream precipitate
• Iodide - yellow precipitate
• You can identify sulfates by adding hydrochloric acid then barium chloride solution to produce a white precipitate of barium sulfate
• Modern instrumental methods of analysis are rapid, accurate and sensitive
• Use the line spectrum to identify a substance in flame emission spectroscopy by comparing
• Instrumental method equipments are usually very expensive and need special training to use it