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CHAPTER 8 : SALTS

CHAPTER 8 : SALTS. Meaning and uses of Salts. A salt is an ionic compound formed when the hydrogen ion, from an acid is replaced by a metal ion or an ammonium ion Example of salts : (i) sodium chloride (ii) potassium carbonate (iii) copper(II) sulphate. Examples of salts :.

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CHAPTER 8 : SALTS

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  1. CHAPTER 8 : SALTS

  2. Meaning and uses of Salts • A salt is an ionic compound formed when the hydrogen ion, from an acid is replaced by a metal ion or an ammonium ion • Example of salts : (i) sodium chloride (ii) potassium carbonate (iii) copper(II) sulphate

  3. Examples of salts :

  4. Examples of salts :

  5. Salts with their uses.

  6. Salts with their uses.

  7. Salts with their uses.

  8. Pb2+ Ba2+ SO42- Ca2+ NO3- Na+ K+ CO32- NH4+ Water Pb2+ Ag+ Cl- Hg+ Identify soluble and insoluble salt.

  9. All sodium, potassium and ammonium salts are soluble in water. • All nitrate salts are soluble in water. • All sulphate salts are soluble in water except lead(II) sulphate, barium sulphate and calcium sulphate. • All chloride salts are soluble in water except lead(II) chloride, silver chloride and mercury chloride. • All carbonate salts are insoluble in water except sodium carbonate, potassium carbonate and ammonium carbonate

  10. State whether each of the following salt is soluble or insoluble in water

  11. Chemical and ionic equations for reactions used in the preparation of soluble salts • General equation for preparing soluble salts. a. metal + acid  salt + hydrogen b. metal oxide (or metal hydroxide) + acid  salt + water c. alkali + acid  salt + water d. metal carbonate + acid  salt + water + carbon dioxide

  12. Complete the following chemical equation. • Mg + H2SO4 MgSO4 + H2 • CuO + HCl  CuCl2 + H2O • Zn(OH)2 + HNO3 Zn(NO3)2 + H2O • NaOH + HCl  NaCl + H2O • MgCO3 + H2SO4 MgSO4+ CO2 + H2O

  13. Preparation of soluble salt

  14. Preparation of soluble salt

  15. The reactants which are needed to prepare the following soluble salts: • Copper(II) sulphate : Copper(II) oxide / hydroxide / carbonate + sulphuric acid • Zinc chloride : Zinc / (zinc oxide / hydroxide / carbonate) + hydrochloric acid • Potassium nitrate : potassium hydroxide + nitric acid • Ammonium sulphate : aqueous ammonia + sulphuric acid • Magnesium nitrate : Magnesium / (magnesium oxide / hydroxide / carbonate) + nitric acid

  16. Chemical equation can be simplified into an ionic equation. • Example : • Chemical equation : Zn(s) + H2SO4(aq)  ZnSO4(aq) + H2(g) • Zn(s) + 2H+(aq) + SO42-(aq)  Zn2+(aq) + SO42-(aq) + H2(g) • Ionic equation : Zn(s) + 2H+ (aq)  Zn2+ (aq) + H2(g)

  17. Chemical equation can be simplified into an ionic equation. • Chemical equation : Mg(s) + 2HCl(aq)  MgCl2(aq) + H2 (g) • Mg(s) + 2H+(aq) + 2Cl-(aq) Mg2+(aq) + 2Cl-(aq) + H2(g) • Ionic equation : Mg(s) + 2H+ (aq)  Mg2+ (aq) + H2(g)

  18. Chemical equation can be simplified into an ionic equation. • Chemical equation :MgO(s) + 2HCl(aq)  MgCl2(aq) + H2O (l) • MgO(s) + 2H+(aq) + 2Cl-(aq) Mg2+(aq) + 2Cl-(aq) + H2O(l) • Ionic equation : MgO(s) + 2H+ (aq)  Mg2+ (aq) + H2O (l)

  19. Chemical equation can be simplified into an ionic equation. • Chemical equation :NaOH (aq) + HNO3 (aq) NaNO3 (aq) + H2O (l) • Na+(aq) + OH-(aq) + H+(aq) + NO3-(aq) Na+(aq) + NO3-(aq) + H2O(l) • Ionic equation :OH- (aq) + H+ (aq)  H2O (l)

  20. Chemical equation can be simplified into an ionic equation. • Chemical equation :CuCO3(s) + H2SO4(aq) CuSO4(aq) + CO2(g) + H2O(l) • CuCO3(s) + 2H+(aq) + SO42-(aq) Cu2+(aq) + SO42-(aq) + CO2(g) + H2O(l) • Ionic equation : CuCO3 (s) + 2H+ (aq)  Cu2+ (aq) + CO2 (g) + H2O (l)

  21. The procedure for the preparation of soluble salts of sodium, potassium and ammonium

  22. The procedure for the preparation of soluble salts of sodium, potassium and ammonium

  23. The procedure for the preparation of soluble salts of sodium, potassium and ammonium

  24. The procedure for the preparation of soluble salts of sodium, potassium and ammonium

  25. The procedure for the preparation of soluble salts of sodium, potassium and ammonium

  26. The procedure for the preparation of soluble salts of sodium, potassium and ammonium

  27. The procedure for the preparation of soluble salts of sodium, potassium and ammonium

  28. The procedure for the preparation of soluble salts of sodium, potassium and ammonium

  29. Preparation of soluble salts (not sodium, potassium or ammonium salt)

  30. The procedure for the preparation of soluble salts of sodium, potassium and ammonium

  31. The procedure for the preparation of soluble salts of sodium, potassium and ammonium

  32. The procedure for the preparation of soluble salts of sodium, potassium and ammonium

  33. The procedure for the preparation of soluble salts of sodium, potassium and ammonium

  34. The procedure for the preparation of soluble salts of sodium, potassium and ammonium

  35. The procedure for the preparation of soluble salts of sodium, potassium and ammonium

  36. The procedure for the preparation of soluble salts of sodium, potassium and ammonium

  37. Chemical and ionic equations for reactions used in the preparation of insoluble salts • Insoluble salts can be prepared by precipitation method through double decomposition reaction. In this reaction, two different aqueous solution mutually exchange their ions , to form precipitate. • Soluble salt solution + Soluble salt solution  Insoluble salt MX containing cation M+ containing anion X- • Chemical equation : AgNO3 (aq) + NaCl (aq) AgCl (s) + NaNO3(aq) • Ionic equation : Ag+ (aq) + Cl- (aq)  AgCl (s)

  38. Preparation of insoluble salts Example 1: Barium sulphate, • Solution 1: Barium chloride/nitrate • Solution 2 :sodium/potassium sulphate • Chemical equation :BaCl2 + Na2SO4 BaSO4 + 2NaCl • Ionic Equation : Ba2+ + SO42-  BaSO4 • Observation : White precipitate formed

  39. Preparation of insoluble salts Example 2 :Copper(II) carbonate, CuCO3, • Solution 1:copper(II) nitrate/sulphate/chloride • Solution 2 :Sodium/potassium carbonate • Chemical equation :Cu(NO3)2 + Na2CO3 CuCO3 + 2NaNO3 • Ionic Equation : Cu2+ + CO32-  CuCO3 • Observation : Green precipitate formed

  40. Preparation of insoluble salts Example 3 : Lead(II) chromate(VI),PbCrO4, • Solution 1:lead(II) nitrate • Solution 2 :Sodium/potassium chromate(VI) • Chemical equation :Pb(NO3)2 (aq) + K2CrO4(aq)  PbCrO4(s) + 2KNO3(aq) • Ionic Equation : Pb2+ + CrO42-  PbCrO4 • Observation : Yellow precipitate formed

  41. The preparation of insoluble salts

  42. The preparation of insoluble salts

  43. The preparation of insoluble salts

  44. The preparation of insoluble salts

  45. The preparation of insoluble salts

  46. The preparation of insoluble salts

  47. Solve problems involving calculation of quantities of reactants or products in stoichiometric reactions Example 1 : A student prepares copper (II) nitrate by reacting copper (II) oxide with 100 cm3 1.5 mol dm-3 nitric acid. Calculate the mass of copper (II) oxide needed to react completely with the acid. [Relative atomic mass: Cu, 64 ; O, 16] Solution : Chemical equation : CuO + 2HNO3  Cu(NO3)2 + H2O Mole ratio : 1 mole 2 mole 1 mole 1 mole Number of moles of HNO3 = 1.5 x 100 = 0.15 mol 1000 Mole ratio of CuO : HNO3 = 1 : 2 Number of mole of CuO = 1 x 0.15 = 0.075 mole 2 Mass of CuO = 0.075 x (64 + 16) = 6 g

  48. Question : 1. Excess zinc powder is added to react completely with 50 cm3 of 2.0 mol dm-3 hydrochloric acid. (a) Write an ionic equation for the reaction between zinc and hydrochloric acid. Zn + 2HCl  ZnCl2 + H2

  49. Question : • Calculate the number of moles of hydrochloric acid used. No of mole of HCl mol = 2.0 x 50 = 0.1 mol 1000

  50. Question : (c) Calculate the volume of hydrogen gas liberated at room conditions. [Molar volume: 24 dm3 mol-1] Mole ratio HCl : H2 = 2 : 1 No of mole of H2 = 1/2 x 0.1 = 0.05 mol Volume of H2 = 0.05 x 24 dm3 = 1.2 dm3

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