Presence of Catalyst

Presence of Catalyst

  1. A catalyst is a substance which can change the rate of reaction.
  2. There are 2 types of catalyst:
    1. Positive catalyst – Increase the rate of reaction.
    2. Negative catalyst – Reduce the rate of reaction.

Experiment 1

Set 1: Zinc + Hydrochloric Acid
Set 2: Zinc + Hydrochloric Acid + Copper Sulphate (Catalyst)

Chemical Reaction:

Zn + 2HCl → ZnCl2 + H2

Result:

Copper(II) sulphate acts as a catalyst to increase the rate of reaction between zinc and hydrochloric acid

Conclusion
The presence of catalyst increases the rate of reaction.

Experiment 2
Set 1: Decomposition of Hydrogen Peroxide
Set 2: Decomposition of Hydrogen Peroxide + Manganese(IV) Oxide (Catalyst)

Chemical Reaction: 

2H2O2 → 2H2O + O2

Result:

Manganese(IV) oxide acts as a catalyst to increase the rate of reaction between zinc and hydrochloric acid

Conclusion:
The presence of catalyst increases the rate of reaction

Note:
In SPM, you need to remember the catalyst used in both the chemical reaction above.

Characteristic of Catalyst

  1. A catalyst is a substance which can change the rate of reaction.
  2. There are a few things you need to know about catalyst:
    1. Chemically, the catalyst remain unchanged during a reaction.
    2. Catalyst does not change the quantity of products.
    3. Catalyst is specific, which means different chemical reaction may have different cataly
    4. Just a small amount needed to achieve big increase in rate of reaction.
    5. More amount of catalyst used can further increase the rate of reaction.
    6. Catalyst in powder form can further increase the rate of reaction.
    7. Catalyst may undergo physical change in a reaction.

List of Reactions and the Catalyst

Chemical ReactionCatalyst
 Decomposition of hydrogen peroxide:
2H2O2 → 2H2O + O2
Manganese(IV) oxide, MnO2
Lead(II) oxide, PbO
Lead(IV) oxide, PbO2
 Reaction between Zinc and Hydrochloric Acid:
Zn + 2HCl → ZnCl2 + H2
Manganese (IV) oxide, MnO2
Copper (II) oxide, CuO
Zinc Oxide, ZnO
Silicon (IV) oxide, SiO2
 Decomposition of Potassium Chlorate (V):
2KClO3 + 2KCl  3O2
 Copper (II) sulphate, CuSO4
Copper (II) chloride, CuCl2
Copper (II) nitrate, Cu(NO3)2
 Haber Process
N2 + 3H2  2NH3
 Iron
 Contact Process
2SO2 + O2  2SO3
 Vanadium(V) oxide, V2O5
 Ostwald Process
4NH3(g) + 5O2(g)  4NO(g) + 6H2O(1)
Platinum

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