Chemical Tests

Silver (Ag) Nitrate Test - dissolve the sample in water - add nitric acid (prevent false positives) - add silver nitrate Cl - white Br - cream l - Yellow

• Add hydrochloric acid, look for effervescence • If there is effervescence, bubble through limewater • Carbonate is present if gas turns limewater cloudy

• add hydrochloric acid, look for effervescence • if there is no effervescence add barium chloride solution • if sulphate ions are present a white precipitate forms with Barium ions

Lit splint Hydrogen = squeaky pop

Glowing splinter relights in the presence of oxygen

Add anhydrous copper sulphate Observe colour change from white to blue

Damp blue litmus paper turns white

Red litmus paper turns blue

• Dip nichrome wire in Hydrochloric acid to clean it • Dip wire in sample • Hold wire in non luminous Bunsen burner (blue flame - to identify colour change)

Li - Red Na - Yellow K - Lilac Ca - Red/Orange Cu - Blue/green

• Dissolve sample in water • Add sodium Hydroxide (NaOH) and warm it • Test the gas for ammonia - red litmus paper turns blue

• Dissolve sample in water • Add sodium Hydroxide Results: Copper = Blue Iron (ll) = Green Iron (III) = Brown

• Flame tests - Li, Na, K, Ca, Cu • Sodium Hydroxide test - Cu, Fe (ll), Fe (lll) • Ammonia test - NH4

• Halides using nitric acid & sliver nitrate - Cl, Br, I • Carbonates - CO3 ²- • Sulphate using HCl and Barium chloride - SO4 ²-

Distance travelled by dye/Solvent front

• Draw a start line in pencil on chromatography paper • Add spots of different dyes along the line at regular intervals • Place paper into a beaker of solvent - solvent must be below pencil line • Allow solvent to move up paper • Mark out where solvent has reached - solved front • Remove paper from beaker and allow to dry

To remove ions that might also produce a precipitate To prevent a false positive