Chemistry Coursework Rate Of Reaction Sodium Thiosulphate

All of my results were accurate and fitted the pattern of results. I did not have any problem whilst carrying out my investigation apart and do not believe I could have done it any better without specialist equipment with plenty of time.

The quality of my evidence is good. There were no points on my scatter graph that were not on or close to the line of best fit. The range of my results were also suitable to make good observations and conclusions

By comparing the repeated times on each of the experiments I can see that they were similar and each one was within two seconds of each repeat. From this evidence I believe my results were very reliable.

My prediction that for every increase of 10°C, the time taken for the sodium thiosulphate to become cloudy is halved was only true for some of the temperatures, and therefore I cannot say that my prediction was correct. This might have occurred for several different reasons, such as the fact that the temperature control might not have been exactly the same or that my judgement of when the cross may have disappeared might not have been exactly the same for each one. However, I don’t think I could have controlled any of these variables any better than I had done without specialist equipment which I did not have.

In order to provide additional evidence and extend my investigation to find out more and back up my conclusion I could perhaps repeat the experiment using specialist equipment. I could also change the initial volume of either the hydrochloric acid or sodium thiosulphate solution and see if I get a similar pattern of results. If the results were consistent and accurate I could use them to back up my original theory. To further investigate the decomposition of sodium thiosulphate I could change the concentration of hydrochloric acid and sodium thiosulphate or use a catalyst in the reaction.

Overall I think that my investigation was successful in obtaining reliable results.

Rates of Reaction - Sodium Thiosulphate and Hydrochloric acid

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Rates of Reaction - Sodium Thiosulphate and Hydrochloric acid

In this piece of coursework, I will study how concentration affects the rate of reaction. I will do so by timing the reaction of Sodium
Thiosulphate with an acid. In this coursework, I will include background knowledge, prediction, safety, results, calculations, graphs, an analysis, conclusion and an evaluation. In my evaluation I will comment on how reliable my results were and how I could have improved my coursework in any possible way.

The definition of rate of reaction is ‘The speed at which a chemical reaction takes place’. The factors that affect the rate of reaction are: · Use of a catalyst
· Temperature
· Surface area
· Concentration

I will be investigating…show more content…

· Bags or any other obstructions should be removed.

I have done a preliminary experiment to help me decide the range of concentrations to use and how much of a difference in concentration to leave between each one. My preliminary results also show that 5cm3 is a low enough concentration to begin with. My knowledge tells me that
5cm3 will take longer to react because there are less sodium particles that react with the acid. My experiment is time based and I will not have enough time to go lower. I took 10 concentrations in the preliminary test already, and this should show enough of a trend already, so there is no need to do an even lower concentration, as it would not help my experiment in any way.


· 100ml conical flask
· Stopwatch
· Thermometer
· Different size measuring cylinders(5ml, 10ml, 50ml)
· Piece of paper.
· Blue or black pen
· Hydrochloric acid
· Sodium Thiosulphate solution
· Water
· Beakers

To keep this a fair test I have made sure that the acid used is the same amount every time. Also the size of the cross on the piece of paper is the same. The temperature is also the same because the results could be anomalous if tested in different conditions. Same beakers will not be used for different chemicals. This can cause reactions in the beakers and will lead to inaccuracies.


My results clearly show that as the concentration decreases, the time increases in the experiment. This links in with the

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