Investigation to find out the lengths of times for a solution of hydrochloric acid and different amounts of sodium thiosulphate and water to turn from clear to cloudy when there is either more water and less sodium thiosulphate or the other way round.
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Introduction
Introduction This is an investigation to find out the lengths of times for a solution of hydrochloric acid and different amounts of sodium thiosulphate and water to turn from clear to cloudy when there is either more water and less sodium thiosulphate or the other way round. To find this out, I am going to do an experiment and record my results to see what I learn from this. Before I do this experiment, I have some background knowledge that will help me to do this experiment properly. I know that a catalyst (in this case, the sodium thiosulphate) is a substance that when added to a reaction mixture, speeds up the reaction, but at the end remains chemically unchanged. It does this by providing an alternate reactions pathway with a lower activation energy. With this background knowledge, I can therefore make a prediction before I start doing my work on the experiment. I predict that when there is a larger volume of sodium thiosulphate to a smaller volume of water the reaction will happen much ...read more.
Middle
Then I will do the same again. I will pour 50cm� of hydrochloric acid into the conical flask (after washing it out from the first time I used it) but this time I will pour only 10cm� of sodium thiosulphate and the remaining 40cm� will be normal tap water. The reason I did not get rid of the sodium thiosulphate all together and just put 50cm� of water was because if I did that the reaction obviously would not happen. So I kept it, but at a small amount. I then time with the stopwatch how long it would take for the reaction to occur again. I made a note of all my results from this experiment in a table which is on the next page. Results These are my results that I got from the first experiment. Vol Hydrochloric Acid (cm�) Vol Sodium Thiosulphate (cm�) Vol Water (cm�) Time (minutes) 50 50 0 2:16 50 10 40 N/A As you can see, these results tell me very little about what I was trying to find out. ...read more.
Conclusion
We can also tell this from the graphs that I drew, by the way the line moves straight from up to down on the graph. Overall I am happy with how the experiment went and am glad that my prediction turned out to be correct. I made sure I did everything properly so I can assume these results are accurate. If I were to do the experiment again I would do mostly the same things as I have done this time but I would be more careful with how I draw on the cross on the piece of paper beneath the conical flask, in case one is drawn on darker than another one therefore staying visible for longer, which would affect my results as I would be stopping the stopwatch later. So to conclude, I am happy with how the experiment went and I now have proof that my prediction before I did the experiment was correct, so it was a success. ...read more.
This student written piece of work is one of many that can be found in our GCSE Aqueous Chemistry section.
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