Sodium Thiosulphate And Hydrochloric Acid Lab Report

The relationship between the concentration of Sodium Thiosulphate and the reaction rate with Hydrochloric acid

Introduction

The rate of reaction is measured by finding the quantity of product made in a certain time. The rate of reaction can be made faster by an increase of temperature, adding a catalyst, increasing concentration or pressure or making the reactants surface area larger. An increase in temperature causes the particles of the reactants to gain more energy and move faster. Collision theory states that this results in more collisions and more of these collisions will have enough energy to cause a reaction. By adding a catalyst the particles will stick to the sides of the catalyst and this increases the rate of reaction. By

increasing

Conclusion

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This is a rate of reaction table. The table shown in the results section is a table of how long the reaction took. This table shows how quickly the reaction was taking place and how much of the reaction had been done each second

GRAPH

We can see from these graphs and tables that my hypothesis was in fact correct. As the concentration of the Sodium Thiosulphate decreases the rate of reaction also decreases. The rate of reaction is inversely proportional to the time taken for the reaction to be completed and the concentration of Sodium Thiosulphate. As the concentration of

Sodium Thiosulphate decreases so the length of time the reaction takes to be completed increases. This is because as the Sodium Thiosulphate becomes less concentrated it contains fewer particles that can react with the Hydrochloric acid. This means that there is a reduced chance of collisions and therefore the rate of reaction will fall as is stated in the collision theory.

The line of best fit in the rate of reaction (rounded 1/time X 1000) vs. Thiosulphate concentration graph is a straight line with a positive slope and is therefore increasing at a constant rate

The other possibly anomalous result is the final mean result of the 5th experiment. If you look at the rounded mean result in seconds graph you can see that the line of best fit does not go near this mean result of 75 seconds. This is probably because of the lower ambient temperature on the day that we did this experiment that caused a slower rate of reaction and so increased the time taken for the experiment to finish. . If I did the experiment again I would try to do all the experiments in the same day. This would make the ambient temperature more constant and therefore the temperature would affect the results equally.

Another possible source of error was difficulty in judging when the cross disappeared. Possibly we could measure the rate of reaction by collecting the sulphur dioxide produced.

Overall, however, we followed the stated method for each of the experiments and I believe that it went quite well and it gave a good set of results that display the predicted pattern for this experiment.

It supports my conclusion because it shows that the time taken for the experiment to finish is inversely proportional to the concentration of

Sodium