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Introduction

How does the Temperature affect the Rate of the Reaction between Sodium Thiosulphate and Acid Elements That Affect the Rate of Reaction The higher the concentration of a solution, the higher the rate of reaction will be. In this experiment, the more sodium thiosulphate there is compared to water, the higher the rate of reaction will be. This is because there are more particles of sodium thiosulphate reacting with the acid at any one stage in the solution causing the colour change to occur faster. The larger the surface area of a solid reacting in a solvent is, the higher the rate of reaction will be. This is because at any given time, there is more solvent in contact with the surface of the solid because of the higher surface area, therefore there is more solid being 'reacted on' at one time. This factor does not come into our experiment because we are measuring the rate of reaction between two liquids. There is a connection between concentration of liquids and surface area of solids, this connection is because of the theory that the more liquid/solid is in contact with its reactant at one time, the higher the rate of reaction will be. Temperature is the variable in our experiment. ...read more.

Middle

The 100ml measuring cylinder has divisions of 7mm. This enables the accuracy to be read to �3.5mm. The thermometer has divisions of 0.1�C. This enables the accuracy to be read to � 0.05�C. The percentage error of a piece of apparatus is found by finding the estimated error, (accuracy), dividing it by the reading taken on the piece of apparatus and then multiplying it by 100%. e.g 10ml measuring cylinder measured 5ml. Calculation = �0.5/5 x 100% = �10% Treatment of Results The results should be written firstly in a results table like the one shown below. From this results table, two graphs should be drawn one with time on the y-axis and temperature on the x-axis and the other with 1/time on the y-axis and temperature on the x-axis. The line should be drawn as a best-fit curve or a best-fit line according to the arrangement of the points. Any anomalous results should be shown on the graph but not included in the drawing of the line Experiment Concentration (moles/dm3 ) Time(s) Temperature Start(�C) Temperature Finish(�C) 1/time Room Temperature 16 95.76 18 18 0.01 30�C 16 27.64 30 30 0.04 40�C 16 20.23 40 38 0.05 50�C 16 15.82 50 49 0.06 60�C 16 9.16 60 57 0.11 70�C 16 6.45 70 67 0.16 Trial 16 4.16 70 67 0.24 Trial Experiment The fastest reaction time in the ...read more.

Conclusion

We would have been able to take an average of all the results for each temperature which would have given us a much more accurate set of results. Validity - We also did not have enough time to carry out the experiment with smaller temperature gaps, say every 5�C rather than ever 10�C. This would have created a more reliable graph as we there would be more points to plot the line from, we would not be assuming that the line follows a certain curve between points, there would be another point between them that would prove it. If we were to make an improved experiment that would rule out most human errors, we would use the one shown below. An Experiment to More Accurately Record the Rate of Reaction Between Sodium Thiosulphate and Hydrochloric Acid Diagram Method The clamp stand is positioned to securely hold the light sensing apparatus, which is connected to a 6V power supply. Measured carefully 30cm3 of sodium thiosulphate using a 50cm3 graduated measuring cylinder, and also measure 3 cm3 of hydrochloric acid using a 10cc cylinder. Connect the data logger to the light sensor, and position the light sensor to receive the light of the bulb in the enclosed container. Position a small 50 cm3 beaker in the container between the light sensor and bulb and pour the thiosulphate and acid in. The data logger records the loss in visibility through the solution. ...read more.

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