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SALT EXAMPLES : replace Metal ion Sodium chloride replace Ammonium ion Ammonium chloride SALTS: ANION PART COMES FROM THE ACID CATION PART COMES FROM BASES Common Cations Na+ Ca2+ Mg2+ K+ Al3+ Zn2+ NH4+ Pb2+ Common Anions (parent acids) Metal ion Sulfate salts + H2SO4 Chloride salts + HCl Carbonate salts + H2CO3 Nitrate salts + H2NO3 Na + Mg 2+ Na2SO4 MgSO4 NaCl MgCl2 Na2CO3 MgCO3 NaNO3 Mg(NO3)2 Cu 2+ Al 3+ CuSO4 Al2(SO4)3 CuCl2 AlCl3 CuCO3 Al2(CO3)3 Cu(NO3)2 Al(NO3)3 All nitrate salts ; soluble salts Barium nitrate, Calcium nitrate, Silver nitrate, Iron(III) nitrate, Al(NO3)3 Ba(NO3)2 Ca(NO3)2 AgNO3 Fe(NO3)3 Lead(II) nitrate, Potassium nitrate, Sodium nitrate, Copper(II) nitrate, Pb(NO3)2 KNO3 NaNO3 Cu(NO3)2 Aluminium nitrate, NO3- All salts ; soluble salts Ammonium carbonate, Potassium carbonate, Sodium carbonate, Potassium sulphate, Ammonium sulphate, (NH4)2CO3 K2CO3 Na2CO3 K2SO4 (NH4)2SO4 Potassium nitrate, Sodium nitrate, Potassium chloride, Sodium chloride, KNO3 NaNO3 KCl NaCl All carbonate salts ; insoluble salts Magnesium carbonate Calcium carbonate Silver carbonate MgCO3 CaCO3 Ag2CO3 Other names[hide] Silver(I)Carbonate Copper(II) carbonate Zinc carbonate Manganese(II) carbonate CuCO3 ZnCO3 MnCO3 Potassium carbonate Sodium Carbonate K2CO3 Na2CO3 Ammonium carbonate (NH4)2CO3 CO32- All SO42-, Cl- salts ; soluble salts Silver(I) Chloride Lead(II) Chloride AgCl PbCl2 Mercury(II) Chloride Cl- HgCl2 Lead(II) sulphate Calcium(II) sulphate PbSO4 CaSO4 Barium sulphate BaSO4 SO42- Iron(II) Chloride Magnesium Chloride Zinc Chloride Sodium chloride, FeCl2 MgCl2 ZnCl2 NaCl Copper(II) Chloride Copper(II) sulphate Aluminium(II) sulphate CuCl2 Potassium chloride, CuSO4 Al2(SO4)3 KCl SO4 NO3- Cl- 2- PbSO4 CaSO4 BaSO4 AgCl PbCl2 CO32- CLASSIFICATION OF SALTS PREPARATION OF SALTS odium ,Na+ salts otassium, K+ salts mmonium, NH4+ salts PREPARATION OF SOLUBLE SALTS [ SODIUM SALTS / POTASSIUM SALTS / AMMONIUM SALTS ] EXAMPLE PREPARATION OF POTASSIUM CHLORIDE H Cl – K – . OH K Cl LET’S DO THIS: PREPARATION OF POTASSIUM CHLORIDE APPARATUS : Pipette 25mL, Burette 50mL, Conical Flask 250mL MATERIALS : Potassium hydroxide 1.0 M, Hydrochloric acid 1.0 M, Phenolphthalein Use a pipette to transfer 25.0 cm3 of potassium hydroxide solution to a conical flask. Add 2 to 3 drops of Colourless KOH turn to pink. Fill a burette with hydrochloric acid and record the initial burette reading. Record the burette reading to 2d.p Slowly adding the acid into the conical flask and swirl until the indicator turns from pink to colourless. Record the volume of acid used. (V cm3) Record the final burette reading to 2d.p PREPARATION OF POTASSIUM CHLORIDE START OVER AGAIN BUT WITHOUT INDICATOR : To get the pure and neutral salt solution Pipette 25.0 cm3 of the same potassium hydroxide solution into a conical flask. Do not add any indicator. From the burette, add exactly V cm3 of hydrochloric acid to the alkali and swirls and shake well. HEATING/EVAPORATE COOLING FILTRATION DRY Solution salt contains impurities continuous with recrystallisation process PREPARATION OF SOLUBLE SALTS [ OTHER SALTS EXCEPT Na+, K+, NH4+] Metal/ metal oxide/ metal carbonate Pour 50 cm3 of sulfuric acid into a beaker. Warm the acid Use a spatula to add Glass rod copper(II) oxide powder bit by bit into the acid. Stir the Acid mixture well. Continue adding copper(II) oxide until some of it no longer dissolves (excess unreacted metal) See the change of metal solid colour and dissolve Excess unreacted metal (residue) Evaporating basin with salt solution (filtrate) Solution salt contains impurities continuous with recrystallisation process HEATING/EVAPORATE Salt solution Evaporating basin COOLING FILTRATION Rinse with distilled water DRY Glass rod Salt Cystals The crystals are filtered and rinsed with a little cold distilled water. These physical characteristics: • Regulars geometry shapes, such as cubic or hexagonal. • Flat faces, straight edges and sharp angles. • Same angle between adjacent faces. Filter Paper NEUTRALISATION REACTION 1ST TITRATION WITH INDICATOR FIND VOLUME OF ACID 2ND TITRATION NO INDICATOR GET PURE SALT PREPARATION OF SOLUBLE SALTS TRANSFER TO EVAPORATING BASIN HEATING/EVAPORATE COOLING FILTRATION DRY DISSOLVE SOLUTE IN ACID HEATING DISSOLVE METAL IN ACID EXCESS METAL NOT DISSOLVE COMPLETE REACT PREPARATION OF INSOLUBLE SALTS [ ALL CARBONATE SALTS except Na+/K+/NH4+ ] PbSO4 / CaSO4/ BaSO4/PbCl2/ AgCl ] EXAMPLE PREPARATION OF LEAD(II) CHLORIDE Pb NO3 Na Cl Pb Cl2 Na NO3 DOUBLE DECOMPOSITION METHOD – TWO AQUEOUS SOLUTIONS/SOLUBLE SALTS WERE MIX TOGETHER , INTERCHANGE TO PRODUCE TWO NEW COMPOUNDS WHICH ARE AN INSOLUBLE SALT (PRECIPITATE) & AQUEOUS SOLUTION (SOLUBLE SALT). Two aqueous solutions/soluble salts are mixed together [one of the solutions contains the cations of the insoluble salt] [one of the solutions contains the anions of the insoluble salt] The ions of the two aqueous solutions above interchange to produce two new compounds which is an insoluble salt or precipitate, and an aqueous solution. Mixture solutions Filter paper Retort stand Glass rod Precipitate (residue) Distilled water Glas s rod Precipitate (residue) Filter funnel Aqueous Solution (filterate) Filtration : Remove solution from precipitate Rinse : remove other ions from precipitate Precipitate /Soluble salts Filter paper Dry : Dried by pressing between two pieces of filter paper. FLOW CHART : PREPARATION OF INSOLUBLE SALTS MIX - STIR TWO SOLUBLE SALTS FILTRATION REMOVE FILTRATE RINSE REMOVE OTHER IONS DRY PRESS BETWEEN FILTER PAPER PREPARATION OF SALTS REMEMBER : METAL IONS DISPLACE HYDROGEN IONS IN ACID TO FORM SALTS HCl [H+/Cl-] Hydrochloric acid Na+ Ca2+ Zn2+ K+ Al3+ Pb2+ NH4+ Mg2+ Cu2+ Fe3+ Fe2+ HNO3 [H+/NO3-] Nitric Acid H2SO4 [2H+/SO42-] Nitric Acid H2CO3 [2H+/CO32-] Nitric Acid Method/Reaction Reason Type of Salts (Metal) Neutralisation (Titration method) Alkali + Acid Salts + Water Most salts of sodium, potassium, and ammonium ions are soluble. Na+ K+ NH4+ Metal Displacement Metal + Acid Salts + Hydrogen More electropositive metal can be displaced hydrogen ion from acid. Ca2+ Mg2+ Al3+ Zn2+ Metal oxide + Acid Salts + Hydrogen Less electropositive metal not be displaced hydrogen ion from acid. Mostly Cu2+/Pb2+ /Ag+ Metal carbonate + Acid Salts + Water + Carbon dioxide metal carbonate is a solid that cannot dissolves in water, in reaction that solid must be added excessively All above except Na+/K+/NH4+ Reactive metals are magnesium, aluminium, and zinc. Unreactive metals are iron, lead, silver Metal that is less reactive than hydrogen such as copper, lead and silver will not react with dilute acid. Soluble salts of sodium, potassium and ammonium can be prepared by the reaction between an acid and alkali. Metals, metal oxides and metal carbonates are solids that cannot dissolve in water, hence during reaction these solids must be added in excess to make sure all hydrogen ions in acid are completely reacted. Excess solid can be then removed through filtration. Unreactive metals such as lead (Pb), copper (Cu), and silver (Ag) cannot react with dilute acid. So to prepare salt contains lead ions (Pb2+), copper ions (Cu2+) or silver ions (Ag+), we must use either oxide powder or carbonate powder only. Impure soluble salt can be purified through crystallization process