There is a need to improve the rate of a very slow reactions but we need to understand that there are several factors that do alter the rates of reactions.
The rates of reaction is very affected by about six factors like Temperature, Pressure, Concentration , Surface area, Effect of catalyst and presence of light.
I will briefly talk about these factors and how greatly they influence the rates of reactions.
However before we dive into these factors that do influence rates of reaction, I will talk about the parameters that these rates of reactions depend on.
|Parameters that govern rates of reaction
|Frequency of collision Average kinetic energy of particles Activation energy
- Frequency of collision
This is the number of collisions per unit time i.e the number of times the particles hit each other in a given time.
If the frequency of collisions increases then the rate of reaction will increase on the other hand if the frequency of collision decreases the rate of reaction decreases.
- Average kinetic energy of particles
Another parameter is the average kinetic energy of particles, this is the amount of energy contained by reactant particles in a reaction.
It is important to note that the higher the average kinetic energy of particles, the higher the reaction.
The only factor that depends on this parameter is Temperature, the higher the temperature of reactant mixture, the higher the average kinetic energy and thus the higher the rate of reaction.
- Activation energy (Energy barrier)
Activation energy is defined as the minimum amount of energy reactant particles must attain or overcome before reactions will take place.
If the activation energy is high, the rate of reaction will be slow but if the activation energy is low then the rate of reaction will be very fast.
Factors that affect rates of reaction
Sometimes you can hear people talk about four factors that affect rates of chemical reaction or three factors that affect rates of reaction but I want to talk about the whole 6 factors that affect rates of reaction.
Six factors that affect rates of reactions
|Factors that affect rates of chemical reaction
|Increase in Temperature increases the average kinetic energy of particles which increases the frequency of collisions and thus increases the rates of reaction.
|Increase in pressure decreases the volume of reactants vessel and this making the particles to be crowded on a smaller space thus increasing frequency of collisions and thus increasing rates of chemical reactions.
|Increase in concentration increases the number of particles available on a smaller container and thus increasing the frequency of collisions and thus increasing the rates of reactions
|If the surface area increase, the number of particles in contact with the medium increases which increases the frequency of collision and thus increasing rate of reaction
|Addition of a catalyst
|When a catalyst is added, it lowers the activation energy thus providing an alternative pathway of reduced activation energy for reactant particles to follow
|Presence of light
|Some reactions are photochemical which means that they are sensitive to the presence of light. A photochemical reaction is a reaction whose rate depends on the presence of light. Some reaction only react faster when they absorb light energy.
These six factors affect rates of chemical reactions and there is a need personally understand how these factors do affect rates of chemical reaction.