Chemistry notes form4
ONE-SCHOOL.NET
Short Notes: Form 5 Chemistry
Rate or Reaction
Calculation
Rate of Reaction (Average Rate)
Rates of reaction =
Quantity change of reactants/products
Total time for the reaction
If the quantity change is immeasurable
Rates of reaction =
1
Total time for the reaction
Find the Rate From a Graph
Average Rate
Rates At an Instant
The rate of reaction is equal to the slope of the graph The rate of reaction at an instant, t, is equal to the of quantity against time. slope of tangent at that instant.
Rate of Reaction =
Δ(Product)
Δ(Time)
http://www.one-school.net/notes.html
Rate of Reaction =
1
Δ(Product)
Δ(Time)
ONE-SCHOOL.NET
Chemical Reaction
Precipitation of Sulphur
2HCl(aq) + Na2S2O3(aq) ⎯→ 2NaCl(aq) + S(s) + SO2(g) + H2O(l)
Na2S2O3: Sodium thiosulphate
Notes:
1. Yellow precipitate (sulphur) is formed.
2. The reaction is slow.
Potassium Dichromate (VI) with Ethanedioic Acid
Cr2O72- + 14H+ + 3C2O42- ⎯→ 6CO2 + 7H2O + 2Cr3+
Notes:
1. In the reaction, the orange colour of the solution turns into green.
Cr2O72-: dichromate(VI) ion (Orange)
C2O42-: ethanedioate ion (Colourless)
Cr3+ : Chromium(III) ion (green)
Potassium Manganate(VII) with Ethanedioic Acid
2MnO4- + 16H+ + 5C2O42- ⎯→ 10CO2 + 8H2O + 2Mn2+
Notes:
1. Mn2+ is colourless
2. In the reaction, the purple colour of the solution turns into colourless.
MnO4-: Manganate(VII) ion (Purple)
Mn2+: Manganese(II) ion colourless
Decomposition of Hydrogen Peroxide
2H2O2 - ⎯→ 2H2O + O2
Catalyst: manganese(IV) oxide(MnO2), Iron(III) oxide (Fe2O3), silver (Ag)
Haber Process (Manufacture Ammonia)
N2 + 3H2 ⎯→ 2NH3
(More detail in Form 4 Chapter 9)
Contact Process(Manufacture Sulphuric Acid)
2SO2 + O2 ⎯→ 2SO3
(More detail in Form 4 Chapter 9)
http://www.one-school.net/notes.html
2
ONE-SCHOOL.NET
Ostwald Process (Manufacture Nitric Acid)
Stage 1
4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g)
Notes:
1.
Short Notes: Form 5 Chemistry
Rate or Reaction
Calculation
Rate of Reaction (Average Rate)
Rates of reaction =
Quantity change of reactants/products
Total time for the reaction
If the quantity change is immeasurable
Rates of reaction =
1
Total time for the reaction
Find the Rate From a Graph
Average Rate
Rates At an Instant
The rate of reaction is equal to the slope of the graph The rate of reaction at an instant, t, is equal to the of quantity against time. slope of tangent at that instant.
Rate of Reaction =
Δ(Product)
Δ(Time)
http://www.one-school.net/notes.html
Rate of Reaction =
1
Δ(Product)
Δ(Time)
ONE-SCHOOL.NET
Chemical Reaction
Precipitation of Sulphur
2HCl(aq) + Na2S2O3(aq) ⎯→ 2NaCl(aq) + S(s) + SO2(g) + H2O(l)
Na2S2O3: Sodium thiosulphate
Notes:
1. Yellow precipitate (sulphur) is formed.
2. The reaction is slow.
Potassium Dichromate (VI) with Ethanedioic Acid
Cr2O72- + 14H+ + 3C2O42- ⎯→ 6CO2 + 7H2O + 2Cr3+
Notes:
1. In the reaction, the orange colour of the solution turns into green.
Cr2O72-: dichromate(VI) ion (Orange)
C2O42-: ethanedioate ion (Colourless)
Cr3+ : Chromium(III) ion (green)
Potassium Manganate(VII) with Ethanedioic Acid
2MnO4- + 16H+ + 5C2O42- ⎯→ 10CO2 + 8H2O + 2Mn2+
Notes:
1. Mn2+ is colourless
2. In the reaction, the purple colour of the solution turns into colourless.
MnO4-: Manganate(VII) ion (Purple)
Mn2+: Manganese(II) ion colourless
Decomposition of Hydrogen Peroxide
2H2O2 - ⎯→ 2H2O + O2
Catalyst: manganese(IV) oxide(MnO2), Iron(III) oxide (Fe2O3), silver (Ag)
Haber Process (Manufacture Ammonia)
N2 + 3H2 ⎯→ 2NH3
(More detail in Form 4 Chapter 9)
Contact Process(Manufacture Sulphuric Acid)
2SO2 + O2 ⎯→ 2SO3
(More detail in Form 4 Chapter 9)
http://www.one-school.net/notes.html
2
ONE-SCHOOL.NET
Ostwald Process (Manufacture Nitric Acid)
Stage 1
4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g)
Notes:
1.