I again had to rely on the naked eye to record the temp. of the thermometer. Also after removing the solution from the Bunsen burner the temp. tended to fluctuate up and down, resulting in the recorded temp. often not being the temp. at which the expt took place. When the solution was poured and measured, it was often not done accurately meaning some solution was lost, so the amount used was not equal to the amount recorded. Unavailability of enough conical flasks and not rinsing the flask properly after each expt. resulted in deposits contaminating the later expts.
When the two reactants were mixed together in the conical flask by a swirling motion, I could not efficiently record if they were swirled to the same extent every time, meaning some solutions were more mixed than others. Improvements By using electronic instruments that measure both time, light and temp, we would'nt have to rely on the naked eye as we would have exact measurements. We could use a data-logging system, involving a light sensor and computer connection, meaning that results are electronically processed and graphs plotted from the information.
By using a wider range of readings making the expt more accurate e. g. using a gap of 5i?? c between the different temp. used rather than a gap of 10i?? c. As we could have more varied results, which is good for picking the best results as you have lots of choice. We could decide the end of the reaction more accuratly if we used a colourimeter which measures the intensity of light being transmitted through the mixture. By keeping every aspect of performing the expt such as pouring, measuring and swirling constant, we could reduce room for error.
By waiting a while before starting the expt to let the Sodium Thiosulphate's temp settle, to ensure that the figure taken down in the temp during the expt. Limitations After a temp rise of 70i?? it became impossible to record the time taken for the cross to disappear as the reaction took place too quickly. This prevented me from getting a wider range of results. By only testing temp with a difference of 10i?? we limited ourselves as we didn't get many readings which would give more accurate results. So if i repeated the expt I would make sure to have more readings to improve my results.
All in all my results were very accurate with only two anomalous results that can be explained by my sources of error. I still have enough accurate results to form a perfect curve and draw a conclusion from. If I repeated this expt I would take all of the observations I have made from my first expt and make sure that i improved on them, removing room for error and to perfect my results. Extensions I could extend this investigation by performing this expt using my improvements from this expt with different chemical reagents, still keeping all other factors except for temp constant.
Some different expts I could use are: 2HCl + Mg Mg Cl + H 2HCl + CaCO CaCl + CO + H O (The temp is altered at constant intervals in both cases) After performing one of the expts with Hydrochloric acid and marble chips these results were collected: Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Patterns of Behaviour section.
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