attraction between the (few cm3, 1 mol dm-3), dilute oppositely charged ions. sulfuric acid (few cm3, 0.5 mol In the solid state, the dm-3), Optional – bung to fit ions can only vibrate on test tube with a delivery tube the spot, but when they attached dissolve in water, the ions are free to move around. Revise writing ionic formulae from the symbols of common ions, including some with brackets. CC9g Solubility C4.19 Recall the general rules 1) Pour some potassium Students prepare insoluble Demonstrate the which describe the solubility chromate(VI) solution salts. Students prepare a white formation of the same of common types of into a small glass beaker. precipitate of silver chloride. insoluble salt from substances in water: Slowly add some silver This precipitate gradually different solutions e.g. a all common sodium, nitrate solution. changes colour to purple when barium sulfate by potassium and ammonium Students will see an left in light, so dry it in a dark adding magnesium salts are soluble immediate red place. The copper carbonate is sulfate, sodium sulfate b all nitrates are soluble precipitate of silver a blue/green precipitate. and copper sulfate c common chloride are chromate(VI) form. solutions to separate soluble except for those of Explain that when two portions of barium Equipment: for each group: silver and lead solutions containing chloride solution. d common sulfates are soluble salts that react eye protection, 100 cm3 Explain that it is always soluble except those of lead, are mixed, the ions swap beaker, 100 cm3 conical flask the same precipitate barium and calcium over, so silver chromate (or other container to collect that forms as the e common hydroxides and and potassium nitrate filtrate), filter funnel, filter barium ions are carbonates are insoluble are formed. All nitrates paper, glass rod, 25 cm3 reacting with the except those of sodium, are soluble, but silver measuring cylinder, dropper sulfate ions. The other pipette, distilled or de-ionised potassium and ammonium chromate(VI) is insoluble ions are spectator ions.
attraction between the oppositely charged ions. In the solid state, the ions can only vibrate on the spot, but when they dissolve in water, the ions are free to move around. Revise writing ionic formulae from the symbols of common ions, including some with brackets. (few cm3, 1 mol dm-3), dilute sulfuric acid (few cm3, 0.5 mol dm-3), Optional – bung to fit test tube with a delivery tube attached CC9g Solubility C4.19 Recall the general rules which describe the solubility of common types of substances in water: a all common sodium, potassium and ammonium salts are soluble b all nitrates are soluble c common chloride are soluble except for those of silver and lead d common sulfates are soluble except those of lead, barium and calcium e common hydroxides and carbonates are insoluble except those of sodium, potassium and ammonium 1) Pour some potassium chromate(VI) solution into a small glass beaker. Slowly add some silver nitrate solution. Students will see an immediate red precipitate of silver chromate(VI) form. Explain that when two solutions containing soluble salts that react are mixed, the ions swap over, so silver chromate and potassium nitrate are formed. All nitrates are soluble, but silver chromate(VI) is insoluble Students prepare insoluble salts. Students prepare a white precipitate of silver chloride. This precipitate gradually changes colour to purple when left in light, so dry it in a dark place. The copper carbonate is a blue/green precipitate. Equipment: for each group: eye protection, 100 cm3 beaker, 100 cm3 conical flask (or other container to collect filtrate), filter funnel, filter paper, glass rod, 25 cm3 measuring cylinder, dropper pipette, distilled or de-ionised Demonstrate the formation of the same insoluble salt from different solutions e.g. barium sulfate by adding magnesium sulfate, sodium sulfate and copper sulfate solutions to separate portions of barium chloride solution. Explain that it is always the same precipitate that forms as the barium ions are reacting with the sulfate ions. The other ions are spectator ions.
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