Investigating The Rate Of Reaction Between Sodium Thiosulphate And Hydrochloric Acid
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Investigating The Rate Of Reaction Between Sodium Thiosulphate And Hydrochloric Acid In this coursework I am going to be investigating the rate of reaction between sodium thiosulphate and hydrochloric acid. The rate of reaction can be changed by theses 4 factors: 1. Temperature 2. Concentration 3. Catalyst 4. Surface area For this course work I have decided to find out how concentration affects the rate of reaction between Sodium Thiosulphate and Hydrochloric Acid. The equation for this reaction is: Sodium Thiosulphate + Hydrochloric Acid Sodium Chloride + Sulphur + Sulphur Dioxide + Water Na2S203(aq) + 2HCL (aq) 2NaCl(aq) + S(s) + SO2(g) + H2O(l) When Sodium Thiosulphate and Hydrochloric Acid are mixed together, the solution turns from a colourless solution to a cloudy colour gradually change again into a yellow colour solution (This is called Sulphur). Because the solution turns from a colourless liquid to a cloudy colour solution we could use this information to show how concentration affects the rate of reaction. This experiment I am going to carry out is both simple and safe. I will be carrying out this experiment in the school laboratory because of the space and the equipment I will need is widely available. In order for my experiment to be fair I will make sure that the measuring cylinders for the Hydrochloric Acid and Thiosulphate will not be mixed up, after each experiment the measuring cylinders, flasks will be rinsed and dried ready for the next experiment.
The Sodium Thiosulphate will be poured in to the Conical Flask. Then I will add the water with the Hydrochloric Acid this will make up the different concentrations I decided to use. Then I will pour the Hydrochloric Acid will be poured into the flask where the Sodium Thiosulphate is. From the moment the Hydrochloric Acid and Sodium Thiosulphate come in to contact I will begin the timer and measure the time how long it takes for the solution to go cloudy enough so that the paper underneath the flask with the black cross disappears I will stop the timer and record these. For each concentration it will be repeated 3 times. The whole procedure is then repeated. I will then put these results in a table, I will work out the averages and then draw a graph. Safety In my experiment I will try to carry out the experiment as safely as possible. This will include: No running - I will be very careful when doing my experiment. I will be calm and take my time. I will not run because I could fall over, hurt myself, spill chemicals and break glassware. Wipe up spills -If I spill something I will clean it up quickly and appropriately. If I don't someone could slip on chemicals, and hurt themselves. If skin gets in to contact with chemicals it could burn.
Evaluation I think that this investigation went very well and that I carried this experiment to the best of my abilities. My range of 5 concentrations has been enough to plot a graph with a line of best fit and a table of results, which supports my prediction that the higher the concentration of Hydrochloric Acid the quicker the rate of reaction. My graph and table of results are reasonably are quite accurate and is quite reliable. The experiments were done fairly but it could have been even fairer. Because the reaction for each experiment was finished when the black cross on the paper underneath conical flask disappeared this is only seen by the eye. When doing the experiment we had trouble deciding when the black cross-had disappeared because everyone in the group had different eye types, this meant that this experiment wasn't entirely fair in the experiment. To solve this problem we could use a devise called a light dependent resistor. This devise will be fixed in an electrical circuit with an ammeter. The resistor will be placed underneath the flask on top of the x. we can take a trial test and when both the Hydrochloric Acid and Sodium Thiosulphate are added and the x cannot be seen, we can record these results and use these for the testing. This circuit will be used for each test and when the ammeter shows that reading from the trial, stop the timer. This device will give us more accurate and more reliable than my group deciding when the x has disappeared. Razaul Islam 10-2
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Here's what a teacher thought of this essay
This is a good piece of work, with an excellent risk assessment, and shows a good use of data to support the conclusion.
Marked by teacher Kate Gardiner 17/10/2013
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