1. Chemical Changes and Structure
Neutralisation

2. Learning Intentions
We are learning about the uses of acids in food and drink and the impact on our health.
We are learning about different examples of chemicals used to neutralise acids.
We are learning to predict the chemicals produced during neutralisation reactions

3. Success Criteria
I can give examples of food and drinks that are acidic and the effect that they have on our health.
I can carry out experiments and write chemical reactions between acids and metals; metal oxides; carbonates and alkalis.
I can state the meaning of the term base and give different examples of bases.
I can predict the products or reactants involved in neutralisation reactions

4. Neutralising acids Method Add about 10cm3 of acid to a small beaker
Add 5 drops of pH indicator
Add alkali until a colour change is observed

5. Neutralising acids Method Add about 10cm3 of acid to a small beaker
Add 5 drops of pH indicator
Add alkali until a colour change is observed
Repeat with magnesium oxide instead of the alkali

6. Neutralising acids Result
As the alkali was added, the colour changed from red to orange to green
A solid neutraliser such as magnesium oxide also neutralised the acid but it took longer

7. Neutralisers Moves the pH of an acid upwards towards 7
Moves the pH of an alkali downwards towards 7
Can be used to assist us in dealing with problems caused by too much acid ie indigestion, acid soil

8. Neutralising acids with alkalis
acid + alkali salt + water
Salts are ionic compounds which can be produced by neutralisation reactions.

9. Neutralising acids with alkalisEg
HCl + NaOH NaCl + H2O
From acid
From neutraliser

10. Bases and alkalis A base is a substance which neutralises an acid
Examples of bases include metal oxides, metal hydroxides, metal carbonates and ammonia
An alkali is formed from a base which dissolves in water

11. Naming salts
The first part of the name of the salt comes from the base eg
Sodium hydroxide
Magnesium oxide

12. Naming salts The acid gives the second part of the name of a salt
Hydrochloric acid HCl chloride
Nitric acid HNO3 nitrate
Sulphuric acid H2SO4 sulphate

13. Naming salts - examples
Sodium hydroxide neutralises nitric acid

14. Naming salts - examples
Sodium hydroxide neutralises nitric acid

15. Naming salts - examples
Sodium hydroxide neutralises nitric acid
sodium nitrate

16. Naming salts - examples
Magnesium oxide neutralises sulphuric acid

17. Naming salts - examples
Magnesium oxide neutralises sulphuric acid

18. Naming salts - examples
Magnesium oxide neutralises sulphuric acid
magnesium sulphate

19. Naming salts - examples
Nitric acid is neutralised by sodium hydroxide

20. Naming salts - examples
Nitric acid is neutralised by sodium hydroxide

21. Naming salts - examples
Nitric acid is neutralised by sodium hydroxide
sodium nitrate

22. Naming salts - examples
sulphuric acid + sodium hydroxide
Magnesium oxide + nitric acid
Hydrochloric acid + sodium hydroxide
Lithium hydroxide + nitric acid

23. Naming salts - examples
sulphuric acid + sodium hydroxide
sodium sulphate
Magnesium oxide + nitric acid
magnesium nitrate
Hydrochloric acid + sodium hydroxide
sodium chloride
Lithium hydroxide + nitric acid
lithium nitrate

24. Ions with more than one atom
valency 1 valency 2 valency 3
nitrate NO3- sulphate SO42- phosphate PO43-
carbonate CO3-

25. Naming salts – using symbols
Sodium hydroxide neutralises nitric acid

26. Naming salts – using symbols
Sodium hydroxide + nitric acid
NaOH + HNO3

27. Naming salts – using symbols
Sodium hydroxide + nitric acid
sodium nitrate + water
NaOH + HNO3 NaNO3 + H2O

28. Naming salts – using symbols
Sodium hydroxide + hydrochloric acid
NaOH + HCl

29. Naming salts – using symbols
Sodium hydroxide + hydrochloric acid
NaOH + HCl NaCl + H2O

30. More examples
NaOH + H2SO4
HNO3 + NaOH
MgO + HCl

31. More examples NaOH + H2SO4 NaSO4 + H2O HNO3 + NaOH NaNO3 + H2O
MgO + HCl MgCl + H2O

32. Reactions of acids with carbonates
Add 20ml 1M hydrochloric acid to asmall glass beaker

33. Reactions of acids with carbonates
Add 20ml 1M hydrochloric acid to a small glass beaker
Add calcium carbonate using a spatula until the reaction stops

34. Reaction of acids with carbonates
Carbonates react with acids to produce a salt, water and carbon dioxide gas.
carbonate + acid salt + water +
carbon dioxide

35. Carbonates - examples Calcium + hydrochloric calcium + water + carbon
Carbonate acid chloride dioxide

36. Carbonates - examples Calcium + hydrochloric calcium + water + carbon
Carbonate acid chloride dioxide
CaCO HCl CaCl H2O + CO2

37. Reactions of acids with metals
Add 1M hydrochloric acid to a boiling tube until it is approx. ¼ full

38. Reactions of acids with metals
Add 1M hydrochloric acid to a boiling tube until it is approx. ¼ full
Add 2 pieces of magnesium to the boiling tube

39. Reactions of acids with metals
Add 1M hydrochloric acid to a boiling tube until it is approx. ¼ full
Add 2 pieces of magnesium to the boiling tube
Hold a lit wooden taper over the end of the boiling tube

40. Reactions of acids with metals
Magnesium, aluminium, zinc, iron and tin react with acids to produce a salt and hydrogen
metal + acid salt + hydrogen
magnesium + hydrochloric magnesium + hydrogen
acid chloride

41. Reactions of acids with metal oxides
metal oxide + acid salt + water
magnesium + hydrochloric magnesium + water
oxide acid chloride

42. Reactions of acids with metal oxides
metal oxide + acid salt + water
magnesium + hydrochloric magnesium + water
oxide acid chloride
MgO HCl MgCl H2O

43. Salts as ionic compounds
The salts produced by neutralisation reactions are ionic compounds – they contain ions.
sodium NaCl Na+Cl-
chloride

44. Salts as ionic compounds
Ions are charged particles.
They either have a positive or negative charge

45. Aqueous Ionic Compounds
Ions separate in water and move around in solution as separate ions. Sodium chloride (Na+Cl-) could be represented
as –
Cl- Na+ Na+ Na Cl- Cl Na+
Cl Cl- Cl- Na+ Cl- Na+
Na+ Na+ Cl-
Cl- Na+ Na+ Na+ Cl-

46. Chemical Tests
The test for carbon dioxide is that it turns limewater cloudy

47. Chemical Tests
The test for carbon dioxide is that it turns limewater cloudy
The test for hydrogen is that it burns with a pop

48. Chemical Tests
The test for carbon dioxide is that it turns limewater cloudy
The test for hydrogen is that it burns with a pop
The test for oxygen is that it relights a glowing splint

49. Electrolysis DC
Carbon
electrodes
copper chloride

50. Electrolysis
Copper forms at the negative electrode

51. Electrolysis Copper forms at the negative electrode
The copper ion must be positive

52. Electrolysis
Chlorine forms at the positive electrode

53. Electrolysis Chlorine forms at the positive electrode
The chloride ion must be negative

54. Aqueous Ionic Compounds
This can be represented as –
Na+(aq) + Cl-(aq)

55. Ionic Equations Hydrochloric acid + sodium hydroxide
sodium chloride + water

56. Ionic Equations Hydrochloric acid + sodium hydroxide
sodium chloride + water
HCl + NaOH NaCl + H2O

57. Ionic Equations Hydrochloric acid + sodium hydroxide
sodium chloride + water
HCl + NaOH NaCl + H2O
H+(aq) + Cl-(aq) + Na+(aq) + OH-(aq)
Na+(aq) + Cl-(aq) + H2O(l)

58. Ionic Equations - examples
H2SO4 + Mg(OH)2
Ca(OH)2 + HNO3

59. Ionic Equations - examples
H2SO4 + Mg(OH)2 MgSO4 + H2O
Ca(OH)2 + HNO3

60. Ionic Equations - examples
H2SO4 + Mg(OH)2 MgSO4 + 2H2O
Ca(OH)2 + HNO3

61. Ionic Equations - examples
H2SO4 + Mg(OH)2 MgSO4 + 2H2O
2H+(aq) + SO4-(aq) + Mg2+(aq) + 2OH-(aq)
Mg2+(aq) + SO42-(aq) +2H2O(l)
Ca(OH)2 + HNO3

62. Ionic Equations - examples
H2SO4 + Mg(OH)2 MgSO4 + H2O
2H+(aq) + SO4-(aq) + Mg2+(aq) + 2OH-(aq)
Mg2+(aq) + SO42-(aq) +H2O(l)
Ca(OH)2 + 2HNO3 Ca(NO3)2 + 2H2O

63. Ionic Equations - examples
H2SO4 + Mg(OH)2 MgSO4 + H2O
2H+(aq) + SO4-(aq) + Mg2+(aq) + 2OH-(aq)
Mg2+(aq) + SO42-(aq) +H2O(l)
Ca(OH)2 + 2HNO3 Ca(NO3)2 + 2H2O
Ca2+(aq) + 2OH-(aq) + 2H+(aq) + 2NO3-(aq)
Ca2+(aq) + 2NO3-(aq) + 2H2O(l)

64. Spectator Ions
Some ions may be present on both sides of the equation in the same form. These are spectator ions.
Ca2+(aq) + 2OH-(aq) + 2H+(aq) + 2NO3-(aq)
Ca2+(aq) + 2NO3-(aq) + 2H2O(l)

65. Spectator Ions
Some ions may be present on both sides of the equation in the same form. These are spectator ions.
Ca2+(aq) + 2OH-(aq) + 2H+(aq) + 2NO3-(aq)
Ca2+(aq) + 2NO3-(aq) + 2H2O(l)

66. Spectator Ions
Some ions may be present on both sides of the equation in the same form. These are spectator ions.
Ca2+(aq) + 2OH-(aq) + 2H+(aq) + 2NO3-(aq)
Ca2+(aq) + 2NO3-(aq) + 2H2O(l)
2OH-(aq) + 2H+(aq) 2H2O(l)

67. Methods of salt preparation
The product from the neutralisation of an acid with alkalis, metal oxides, hydroxides and carbonates is a SALT
A salt would normally have a positive metal ion and a negative ion from the acid ie sulphate

68. Methods of salt preparation
In setting out to make a salt we must consider
is the salt we want soluble or insoluble
how can we tell if the reaction is complete )ie neutral)
if the salt is soluble, how do we remove the water
how can we remove and dry an insoluble salt

69. Methods of salt preparation
Information on the solublities of salts can be obtained from page 5 of the data book.
Sodium and lithium salts are normally soluble
ammonium salts are always soluble
nitrate salts are always soluble

70. Methods of salt preparation
Insoluble salts can be prepared by mixing two soluble chemicals which react together to give one insoluble solid or precipitate while the other ions remain in solution.
The solid is obtained by filtering, washing and drying in air.

71. Methods of salt preparation
Soluble salts can be made by neutralising an acid with an alkali
eg potassium nitrate can be made by neutralising potassium hydroxide with nitric acid

72. Titration
Titration uses the following equipment -

73. Titration Titration uses the following equipment - Conical flask
burette
pipette

74. Calculations moles = volume (l) x concentration (mol/l)
moles = litres x mol/l
m = v x c m
v c

75. Calculations - example
20cm3 of hydrochloric acid was neutralised by 10cm3 of 2mol/l sodium hydroxide solution. What is the concentration of the acid?

76. Calculations - example
20cm3 of hydrochloric acid was neutralised by 10cm3 of 2mol/l sodium hydroxide solution. What is the concentration of the acid?
write a balanced equation

77. Calculations - example
hydrochloric acid + sodium hydroxide
sodium chloride + water
HCl(aq) + NaOH(aq) NaCl(aq) + H2O
1 mole 1 mole mole 1 mole
1 mole of NaOH neutralises 1 mole of HCl

78. Calculations example 20cm3 HCl neutralises 10cm3 of 2 mol/l NaOH
No of moles of NaOH is

79. Calculations example 20cm3 HCl neutralises 10cm3 of 2 mol/l NaOH
No of moles of NaOH is
m = v x c

80. Calculations example 20cm3 HCl neutralises 10cm3 of 2 mol/l NaOH
No of moles of NaOH is
m = v x c
m = 0.01 x 2

81. Calculations example 20cm3 HCl neutralises 10cm3 of 2 mol/l NaOH
No of moles of NaOH is
m = v x c
m = 0.01 x 2
m = 0.02
The number of moles of HCl also = 0.02

82. Calculations example 20cm3 HCl neutralises 10cm3 of 2 mol/l NaOH
No of moles of NaOH is
m = v x c
m = 0.01 x 2
m = 0.02
The number of moles of HCl also = 0.02

83. Calculations - example
No of moles of HCl = 0.02
m = v x c
0.02 v x 2
v = 0.01 litres or 10cm3

84. Learning Outcomes

85. Learning Outcomes