Sodium Thiosulphate and Hydrochloric Acid Reaction Investigation

Sodium Thiosulphate and Hydrochloric Acid Reaction Investigation

Aim

To see the effects of concentration on the rate of a reaction between

sodium thiosulphate and hydrochloric acid.

Background information

The collision theory briefly: For a reaction to occur particles have

to collide with each other. Only a small percent result in a reaction.

This is due to the energy barrier to overcome. Only particles with

enough energy to overcome the barrier will react after colliding. The

minimum energy that a particle must have to overcome the barrier is

called the activation energy, or Ea. The size of this activation

energy is different for different reactions. If the frequency of

collisions is increased the rate of reaction will increase. However

the percent of successful collisions remains the same. An increase in

the frequency of collisions can be achieved by increasing the

concentration, pressure, surface area, temperature and the addition of

catalysts.

Plan

We must produce a piece of coursework investigating the rates of

reaction. The rate of reaction can be measured by the rate of loss of

a reactant or the rate of formation of a product during a chemical

reaction. It is measured by dividing 1 by the time taken for the

reaction to take place. There are five factors which affect the rate

of a reaction, according to the collision theory of reacting

particles: temperature, concentration (of solution), pressure (in

gases), surface are (of solid reactants), and catalysts. I have chosen

to investigate the effect concentration has on a reaction. It would be

less practical to do surface area, as it is very hard to measure

surface area, and so keep a constant measure of it, pressure is also a

very hard to measure as is temperature, catalyst are also hard to

measure as they can be unpredictable.

The reaction that will be used is:

Sodium Thiosulphate Sulphur Dioxide + Sulphur

+ à +