There has been hints on catalysts and rates of reaction and it is always on how the catalyst can increase the rate of reaction. Catalyst is among the six factors that can increase the rate of a chemical reaction.
Yes, the truth is that the catalyst can increase or speed up the rate of a chemical reaction by decreasing the activation energy therefore providing an alternative pathway of reduced activation energy.
Enzymes too can speed up the rate of biological reactions, there is a similarity between enzymes and catalysts in fact enzymes are biological catalyst.
What is the definition and Properties of a Catalyst?
Before we dive further into the effect of catalyst on rate of reaction, in will just give a quick review on the definition and properties of catalysts.
A catalyst is defined as a substance that speeds up the rate of a chemical reaction by decreasing the activation energy.
|Properties of a Catalyst|
|A catalyst is specific in function|
A catalyst speeds up the rate of chemical reactions
A catalyst reduces activation energy
A catalyst remains chemically unchanged at the end of the reaction.
A catalyst speeds up the rate of both forward and backward reaction in a reversible reaction and so do not affect equilibrium position.
How does a catalyst increase the rate of reaction?
A catalyst increases the rate of a reaction by decreasing the activation energy providing an alternative pathway of reduced activation energy making it easier for products to be formed.
The need for adding catalysts is to reduce the activation energy which prevents or delays the reaction from occurring.
Specific examples of catalysts in some chemical reactions
|Specific Catalyst||Chemical reaction|
|Finely divided iron||Haber process for ammonia production N2 + 3H2 ==2NH3|
|Vanadium V oxide||Contact process for the manufacture of sulphur iv oxide used in making sulphuric acid 2SO2 + O2 ==2SO3|
|Nickel||Hydrogenation of oil|
|Manganesse iv oxide||Decomposition of potassium chlorate V 2KClO3 ===2KCl + 3O2|
Why are most catalysts in powdered or crystalline form?
Yes, to increase the efficiency of the catalyst, it is usually recommended to reduce the particle size of the catalyst leading to powdered or granular form of the catalyst instead of lumps.
This reduction in particle size increases the surface area of catalysts and thus brings more of them to be in contact with the reaction medium thus decreasing the activation energy and increasing the efficiency of the catalyst.
A powdered iron (iron filings) is more effective in Haber process than lumps of iron or granular iron because the iron filings provide a larger surface area for the mixture and thus increasing the efficiency of the reaction.
Why are catalyst important in Chemical systems and environment?
- Catalysts help in the production of green fuel by increasing the speed of the process.
- Catalyst reduces cost of chemical processes and thus contributes to the economy.
- Catalysts help in polymerization of plastics.
- Catalysts also help I the production of very important fine and heavy chemicals that are important to us.
In conclusion, about 90% of chemical reactions can be catalyzed and catalyst can increase the rate of the chemical reactions by decreasing the activation energy of the reactions.