To find out how the concentration of sodium thiosulphate affects the rate at which the acid turns cloudy Essays

To find out how the concentration of sodium thiosulphate affects the rate at which the acid turns cloudy Essays To find out how the concentration of sodium thiosulphate affects the rate at which the acid turns cloudy Essay To find out how the concentration of sodium thiosulphate affects the rate at which the acid turns cloudy Essay Variable:* Temperature.* Size of cross.* Colour of cross.* Amount of acid.* Amount of sodium thiosulphate.* Size of beaker.Prediction: By changing the concentration of the thiosulphate but keeping all other variables the same.I think that the more thiosulphate the longer it will take the acid to turn cloudy.If there is more acid to react with little thiosulphate it should take less time to turn cloudy.Experimental plan: I will measure the time it takes for a cross on the tile under the beaker to vanish, with different amounts of sodium hyposulphite being added.I will keep the volume of fluid the same buy adding water, which is neutral, to the mixture.Apparatus:* Tile* Beaker* 2 x measuring tubes* Marker pen* Sodium thiosulphate* Dilute hydrochloric acid* Water* Stop watchMethod:i. Place the beaker on top of the tile. (Look at diagram).ii. Pour out 10ml of hydrochloric acid in to one measuring tube. In the other put an amount of sodium thiosulphate and top it up to 25ml with water.iii . Pour the 2 measuring tubes in to the beaker and start the stopwatch.iv. When you can no longer see the cross below the beaker on the tile, stop the stopwatch, and record the time.v. Do it with different amounts of sodium thiosulphate.vi. Record the results on a table.vii. Produce a graph and this investigation.Results:Amount of acid (ml)Test1Test2Test3AverageMix of sodium thiosulphateWater (ml)thiosulphate109.409.159.259.27025102.262.152.152.16520101.201.101.051.121015100.500.450.550.501510100.400.400.400.40205Results conclusion:As can be seen the graph goes down in a curve. The first result was very high compared with the others. It looks out of place so I think we may have used the wrong concentration of acid in the mix.My results support my prediction as the more thiosulphate there was in the mix the longer it took to turn cloudy.This was because there was less acid per cmà ¯Ã‚ ¿Ã‚ ½ of thiosulphate.GraphShowing the correlation between time taken to turn acid cloudy and the am ount of thiosulphate added.Evaluation:As previously detailed I believe that our first result was very unexpected compared to all the others. As can be seen it took a lot longer to turn cloudy by quite away. This is shown on the graph and it looks odd and out of place against the other results because it is so much different.I do not know why this has happened, it might have been that we used the wrong strength of acid in the mix, or the wrong amounts of each liquid, but these are the only reasons that I can think of without completing the experiment again.I think that our results are fairly accurate except for the first result on are table 25ml of thiosulphate and no water.We undertook each experiment three times and then took the average, so as to try and eliminate some of the smaller inaccuracies and not to have as many mistakes that could have happened by doing only one experiment at each level of mix.The only reason all our results were not dead accurate was because the measurin g and timing equipment we where using was not the best and relied on our eyesight and attention. We could over come some of the inaccuracies by using better and more precise equipment.We could carry out further experiments to extend this investigation by changing the amount of thiosulphate in increments of 1 ml instead of 5 mls, this would make the final results show up any odd results a lot more than they do in my results now, and would also give us a greater range of figures to work with and from.