Investigating rates of Reaction

Authors Avatar

Investigating rates of Reaction

Aim

The aim is to investigate the effect of changing the concentration of sodium thiosulate on the rate of the reaction between sodium thiosulphate and hydrochloric acid.

Prediction

I think that increasing the concentration will increase the rate of reaction. This is because in order for a chemical reaction to occur particles must collide with sufficient energy to react. This is the activation energy. If the particles do not have enough energy when they collide, they simply bounce off each other.

If two particles move towards each other without the sufficient energy…

…when they collide, they will not react…

…they will simply bounce off one another, and remain un-reacted.

Two particles with enough energy however…

…will collide…

…and react.


In a solution, all of the particles will have different energy levels, only the particles with enough energy (more than the activation energy) will react. On the graph, the Activation energy is the black dotted line, so only the particles with more than this (those in the shaded area) will react. As most of the particles so not have the amount of energy needed to react, the rate of reaction will be quite slow as the chances of these particles colliding are low. Reaction rates can be increased of the concentration of reactants is raised. An increase in concentration produced more collisions. The chance of an effective collision goes up with the increase in concentration.

Join now!

In my preliminary tests, I tested the reaction of the most concentrated HCl, and the least concentrated. Here are my results:

Initially, I was going to change the concentration  of the HCl, however these results are too close together and a small mistake when measuring the reactants would lead to a large error in the results. If I made a 1ml mistake in the 10ml HCl solution, this would lead to a 10% error. If I made a 1ml mistake in the 10ml solution, this would only be a 2% error. So from my preliminary work, I have ...

This is a preview of the whole essay