Sodium Thiosulphate Lab Report

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The experiment chosen for this investigation was sodium thiosulphate and hydrochloric acid. This experiment was executed by adding hydrochloric acid into the sodium thiosulphate, then timing how long it took for the solution to become opaque by waiting until the ‘X’ underneath the solution disappeared. Through this method, reaction rates were investigated to find how factors such as temperature, concentration and mixing can affect it. The balanced chemical equation for this experiment is:
Na¬¬2S2O3 + 2HCl  2NaCl + SO2 + S + H2O
Sodium thiosulphate + Hydrochloric acid  Sodium chloride + Sulphur dioxide + Sulphur + Water
The first experiment conducted tested how concentration affected reaction rate. Using different concentrations of hydrochloric
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Tweaking the method for the first experiment, the sodium thiosulphate were in three different temperature; one was placed on a hotplate and heated, another in an ice bath and the last was room temperature. This showed how the temperature of the solution can be an important factor when investigating reaction rates. The reaction rate of a chemical reaction can be increased by raising the temperature of the reactants. This is because as temperature is increased, the reactant particles move more quickly and have more energy, so the particles collide more often and more collision results in a reaction, therefore the rate of the reaction increases. The average kinetic energy of the molecules also increases when the temperature is raised. According to the collision theory, the rate at which molecules collide impact on the overall reaction rate as the faster the molecules move they have more energy and are more likely to collide with each other. This means that the more the temperature is increased the more energy the molecules have so they will collide more frequently and have an increased reaction rate. This has been shown through the results of the experiment, where three different beakers with different temperatures were tested using the 1M of HCl. Beaker 1 was heated on a hotplate to 47C, taking only 12 seconds for the solution to turn cloudy and opaque. In the second beaker, the beaker was left as the control at room temperature, around 27C, and the reaction rate was 38 seconds. The third beaker was placed in an ice bath until it was 14C, then it took 60 seconds for the solution to turn opaque. 1M of HCl was used for all three tests as the concentration needed to be a controlled variable. These results demonstrate that an increase in temperature of the sodium thiosulphate also increases the reaction

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