Some chemical reactions are usually catalyzed and actually some reaction will occur very slowly without the addition of a catalyst.
The addition of a catalyst to a chemical reaction do only one thing, it speeds up the rates of chemical reactions but by reducing the activation energy.
Chemical reactions can be catalyzed to occur faster because some non-spontaneous reactions will take time to take place if left unaided.
A spontaneous reaction is a reaction that can occur on its own while a non-spontaneous reaction is one that cannot occur without aid.
But the big question is how a reaction is affected by the addition of a catalyst.
There are about three parameters that govern or rule the factors that affect the rate of a reaction.
They are the frequency of collision, average kinetic energy of particles and activation energy.
The six factors that affect the rate of reaction depend on these parameters.
|Temperature||Concentration||Surface area||Effect of catalyst||Effect of light||Pressure|
|Average kinetic energy Frequency of collision||Frequency of collision||Frequency of collision||Activation energy||Average kinetic energy||Frequency of collision|
You can see that the only factor that affect activation energy is Catalyst and how does the catalyst do that?
I will explain this briefly, but I will like you to know that these factors help make the reaction go faster or even slow if you don’t know how to monitor the rate of reaction.
How are the following aspects of a reaction affected by a catalyst?
A catalyst first is a substance that speeds up the rate of chemical reaction but by decreasing the activation energy that is hindering or preventing reactions from occurring.
If any reaction occurs slowly, it must be that the activation energy is high all other factors being equal.
When the activation is very small then we do not have issues because reaction will still occur very fast if other factors are also maintained on the other hand, reaction rate will slow down when the activation energy is high.
In general, reaction rate occurs very fast when the activation energy is small, and reaction occur with difficulty when the activation energy is very high.
So, a catalyst affects the rate of a chemical reaction by decreasing the activation energy but there is a need to understand activation energy is reduced.
How does a catalyst affect rates of reactions?
A catalyst is mainly concerned with the energy preventing or delaying reactions from occurring.
This energy that prevents or delays reactions from occurring is called the activation energy.
An activation energy is the minimum amount of energy that must be overcome or equaled before chemical reaction will take place.
To fully understand this phenomenon, please take a look at the schematic sketch of the energy profile diagram of the exothermic reaction.
From the diagram, you can see the lower energy profile is the catalyzed reaction that passes through the alternative pathway of a reduced activation energy.
From the energy profile diagram, it is important to understand that the enthalpy change is equal to the change in the energy content of reactants and products.
Enthalpy change = Energy content of products – energy content of reactants
It is important to note that exothermic reactions release energy while endothermic reactions absorb energy.
Explain the mechanism of a catalyst on rates of reaction.
The simple mechanism of the effect of a catalyst is that once a catalyst is added to the Chemical reaction, it quickly reduces the activation energy.
However, we usually make reference to the positive catalyst because a negative catalyst inhibits the reaction though that is not so important in this context.