The Rate Of A Reaction Between Hydrochloric Acid And Sodium Thiosulphate

The Rate Of A Reaction Between Hydrochloric Acid And Sodium Thiosulphate

Aim: I am going to investigate the effect of changing the

concentration of Sodium Thiosulphate on the rate of the reaction

between Hydrochloric Acid and Sodium Thiosulphate.

Prediction: I predict that as the concentration of the Sodium

Thiosulphate doubles, the rate of the reaction will double. I believe

that when the most concentrated solution is used the reaction would be

at its fastest.

Collision Theory: In a more concentrated solution there are more

particles so collisions occur more frequently. The more often they

collide the faster they react. This means that the rate of reaction

will increase if the concentration of the reactants is increased. As

shown below:

Key=

Sodium Thiosulphate

Hydrochloric Acid

Less concentrated solution More concentrated solution

Independent Variable

The variable that I am going to change is the concentration of Sodium

Thiosulphate.

Dependent Variable

The dependent variable is the time in which the solution becomes

cloudy thus hiding the X.

Controlled Variables

The controlled variables are the temperature, concentration of the

acid, volumes of the Sodium Thiosulphate and the Hydrochloric Acid,

Agitation/stirring.

A factor which may change my results could be how I perceive that the

X is marked.

Summary Method

My investigation is how the concentration of Sodium Thiosulphate will

affect the rate of reaction. I will be using a range of concentrations

from 10cm to 50cm to make it easier to see the difference in a graph.

I then have to record the time taken for the reaction to finish. Once

I have completed the 5 experiments I will use a table to gather my

results and a graph to interpret them. However before I gather my

results I will repeat the experiments for reliability and accuracy.

Apparatus/Equipment

The following apparatus is what I need for this experiment:

* 3 measuring cylinders

* 2 conical flasks

* 1 stopwatch