Melissa Romera
Chemistry Coursework
Aim
In an experiment to investigate the effect of temperature on the rate of reaction, the volumes and concentration of the sodium thiosulphate solution and dilute hydrochloric acid are kept the same. I am going to investigate how changing a concentration of sodium thiosulphate affects the rate of reaction between sodium thiosulphate and hydrochloric acid.
Prediction
I predict that the lower concentration of sodium thiosulphate and the higher concentration of water the faster the reaction will be. I think this because water dilutes the sodium thiosulphate like it dilutes juices. More amount of water is the more concentration there will be. Having more of water will make the particles collide quicker causing the time be a lot quicker. It will have activation energy.
Plan
To start this experiment of you will need to measure out 20cm of sodium thiosulphate and 10cm of hydrochloric acid into two separate measuring cylinders. Also measure out 40cm of water. Collect a clonical flask and poor the 40cm of water and 20cm of sodium thiosulphate into the clonical flask. When you are ready with a stopwatch poor the 10cm of hydrochloric acid into the flask with the mixture. As soon as the acid is poured into the mixture start the stopwatch. The flask will need to be standing on an X as a mark. When you can no longer see the mark stop the stopwatch and record your results.
Repeat this 6 times but changing the amount of sodium thiosulphate and water. You will need to do a trial before you start the first experiment to check whether you are doing the investigation right. Once you have done the trial you will need to record 2 sets of results to get a clear set of results so that it is a fair test.
The reason for using this method because I feel like these volumes will give me a good set of results and doing up to 6 temperature it will give me a clear average for my graph of reaction.
