What is collision theory in Chemistry?
Collision theory in Chemistry deals with the reactant particles hitting each other in order to form products but this only happen when the collision generates energy equal or more than the activation energy.
The Collision theory of reactions can only be understood and appreciated from the angle that it takes hitting of particles with each other or among one another before products will be formed.
However not all the collision of particles of reactants lead to the formation of products, only a fraction of these collisions called effective collision that led to the formation of products.
Collision theory in Chemistry states that no reaction will occur until there is collision between reactant particles and only a fraction of these collisions leads to the formation of products.
How does collision theory affect reaction rate?
The reaction of reactants in chemical reaction only occurs when particles collide with each other and if there is no reaction then there will be no reaction.
As reactant particles continue to collide, they generate energy and until the energy generating equals or overcomes the energy barrier which is otherwise called the activation energy no reactions will take place.
Terms associated with Collision theory in Chemistry.
| 10 common Terms associated with Collision theory in Chemistry. |
| Reaction rate: This is the amount of products produced per unit time in a reaction. OR This is the amount of reactants consumed per unit time in a reaction. OR This is the amount of reactants converted to products per unit time in a reaction. |
| Frequency of collision: This is the number of times reactant particles hit each other per unit time. |
| Activation energy: This is the minimum amount of energy that must be equaled or overcome by reactant particles before chemical reactions will take place. |
| Catalyzed reaction: This is reaction involving a catalyst providing a reduced activation pathway. |
| Uncatalyzed reaction: This is the reaction that is not aided with a catalyst and so occur without the addition of a catalyst |
| Collision theory: This state’s that no reaction will take place until there is collision between the reactant particles and only a fraction of these collisions leads to products. Hint : Not all collisions lead to the formation of products |
| Effective collision: This is the type of collisions that leads to the formation of products by generating energy equal or greater than the activation energy. |
| Ineffective collisions: This is the type of collisions that does not lead to the formation of products because energy generated is less than the activation energy. |
| Rate Curve: This is the graph that shows the rate of a reaction against time indicating the rate at which a reaction occur at every particular time |
| Reaction pathway: This is the path taken by the reaction to arrive at product formation |
Collision theory and rate curve of reaction
Now, I want to explain a little about the rate curve or graph of reactions though using collision theory.
The rate curve or graph indicates the rate of reaction at any time of the reaction.
Analysis from the rate curve
At stage A
Reaction is fastest because it is the initial time of reaction since that is the point of highest concentration of reactant particles.
Consequently, the level of collisions is highest and thus reaction rate is highest at this point.
At stage B
At this stage, concentration has decreased a little since and as result collisions of particles has also decreased since there are now fewer particles remaining in the vessel.
So the rate of reaction in stage B is less than the rate of reaction in stage A due to difference in the collision of particles in the two stages.
At stage C
At this point, no reaction occurs again due to the fact that no collision is taking place anymore. This could be as a result of one of the reactants finishing which is usually called the limiting reactant or reagent.
Whenever you have two reactants in a chemical reaction, as time proceeds one of the reactants usually finishes first and that determines the amount of products formed and there is a way you can determine or calculate the limiting reagent in every reaction easily.
Recall that collision theory governs factors affects the rate of a chemical reaction so if collision increases reaction rate increases but when collision decreases reaction rate decreases.
So, I can boldly say that the rate of a chemical reaction depends on the number of collisions at that time of reference because that will lead to the frequency of effective collisions, so this is the collision theory.
In conclusion, Collision theory in Chemistry and rate curve is a very important aspect of chemical kinetics and help in fully understanding the nature of rates of reactions.
