1. 7.3 Making salts from solutions Soluble or insoluble? What do these terms mean? 17 September 2015 Fertilisers Water Treatment

2. 7.3 Making salts from solutions Indicators are needed to check producing a soluble salt from an alkali and acid. Insoluble salts produce a precipitate when reacting two solutions. Precipitation is an important way of removing some substances from waste water. 17 September 2015 Soluble = Able to dissolve in a solvent. Insoluble = Unable to dissolve in a solvent. Precipitate = A solid material produced from a solution.

3. Acid + alkali acid alkalia saltwater A neutralisation reaction is where an acid reacts with a alkali to produce a neutral solution of a salt and water. 1214131211109876543 Increasingly acidIncreasingly alkali sodium hydroxide pH 14 hydrochloric acid pH 1 neutralisation sodium chloride pH 7 Salt alkali How can the salt be separated from the water?

4. Neutralisation reactions: hydroxides Each OH - ion reacts with one H + ion. Reaction with hydroxides: H + + OH -  H 2 O Eg. Potassium +hydrochloric  water + potassium hydroxide acidchloride OH HH 2 O KOH+ HCl  H 2 O+KCl Eg. Calcium +sulphuric  water + calcium hydroxide acidsulphate OH 2 H 2 2H 2 O Ca(OH) 2 + H 2 SO4  2H 2 O+CaSO 4 Water can be evaporated to leave the salt behind.

5. Insoluble Salts A precipitation reaction leaves behind a solid material. E.g. Lead Nitrate + Sodium Chloride → Lead Chloride + Sodium Nitrate Pb(NO 3 ) 2 (aq) + 2NaCl (aq) → PbCl 2 (s) + 2NaNO 3 (aq) Practical 1.Add sodium chloride to lead nitrate and stir. 2.Filter the precipitate. 3.Wash and dry precipitate. Place on a watch glass. 4.Write down what the Lead Chloride looks like.

6. Filtering

7. 7.3 Making salts from solutions Indicators are needed to check producing a soluble salt from an alkali and acid. Insoluble salts produce a precipitate when reacting two solutions. Precipitation is an important way of removing some substances from waste water. 17 September 2015 Soluble = Able to dissolve in a solvent. Insoluble = Unable to dissolve in a solvent. Precipitate = A solid material produced from a solution.