The Rate of Reaction Between Sodium Thiosulphate and Hydrochloric Acid

The Rate of Reaction Between Sodium Thiosulphate and Hydrochloric Acid

Aim:

I am going to investigate how changing the concentration of Sodium

Thiosulphate affects the rate of reaction with Hydrochloric Acid. I am

going to time how many seconds/minutes it takes until you can no

longer see the black cross on a piece of paper under the beaker. Each

time I do the experiment, I will change the amount of thiosulphate and

water in the reaction mixture. I want to find out if the concentrated

thiosulphate makes the reaction go quicker.

Background Information

For a chemical reaction to take place, the particles have to collide

with enough energy for something to change.

There are five factors that will affect the rate of reaction that we

need to take into consideration, these are:

* Temperature - I will conduct all the tests at room temperature

(hopefully on the same day) because temperature has an effect on

the rate of the reaction.

* Concentration - I will try my best to use all the acid from the

same bottle, which then makes it more of a fair test as all the

acid should be the same concentration.

* Surface Area - This will not affect any of my results, as we are

not using any solids in the investigation.

* Catalyst - This speeds up reactions.

* Pressure - The pressure will be the same in each of the

experiments, as we will try to use exactly the same amount of acid

in each experiment and the same size beaker.

Prediction!

I predict that the greater the concentration of Sodium Thiosulphate in

the solution, the faster the chemical reaction will take place.

Therefore, the cross will disappear more quickly due to the cloudiness

of the solution.

I think that the concentration of a solution affects the rate of