When the Temperature is decreased:
When the Temperature is increased:
Fair Test
For each experiment, the stop clock needs to begin as soon as the sodium thiosulphate mixes with the hydrochloric acid, making it a fair and reliable test. Otherwise if the stop clock is started halfway through the experiment, the results become unreliable and variable.
Also, the temperature in each experiment should be recorded precisely, measuring the exact temperature of the sodium thiosulphate just before mixing it with the hydrochloric acid. If not, the results will be inaccurate and there will not be a clear pattern showing how the temperature affects the Rate of Reaction.
Another way of making sure that the experiment is fair for every result, is to ensure that the volume of the acids are equal in every experiment, by measuring it out in the measuring cylinder before adding it to the beaker, and also not to measure out the two solutions in the same measuring cylinder before the experiment, otherwise the solution will have already mixed to form a cloudy solution before the experiment begins, thereby making it very unreliable.
Also if the amount of sodium thiosulphate was more, it will affect the experiment, because the more sodium thiosulphate in the experiment, the more particles, meaning it will affect the Rate of Reaction.
Safety Test
When dealing with acids in a lab, you should always wear goggles in case there is a spillage, which could be very harmful and cause the Acid to burn your skin and eyes,
Another basic rule when in the lab working with Acids is, never run around. This floor could be very slippery and if your holding acids you could harm yourself and others working nearby.
Always tie your hair when doing practical experiments, especially when working near a Bunsen Burner. You could get distracted for a moment and the situation could be fatal.
Observation
Here are the Results I have collected from my experiment in the form of a table:
Table
Table showing my First set of Results at Different Temperatures
From Table 1, it is clear to see that there is a steady decrease in the amount of time taken for the solution to turn cloudy. But around 30º to 40º there is a sudden drop in time, clearly showing that the Temperature speeds up the Rate of Reaction.
Table 2
Table showing my Second set of Results at Different Temperatures
From Table 2, it more or less shows that there is a definite drop in the Rate of Reaction between 30º and 40º, and that the Reaction speeds up when the Temperature is increased.
Graphs
On the next two pages are Graphs showing the Results for Experiment One and Experiments Two, which correspond with the Table Results shown above:
Conclusion
From the Investigation I have conducted, it is clear to see from my results that: If the Temperature increases, the particles will react more vigorously meaning more collisions, speeding up the reaction.
If the temperature decreases the particles will react languorously, meaning less collisions, slowing down the reaction, matching with my Predictions.
From Background reading, I have also discovered that ‘When performing the experiment at different temperatures and measuring the time Intervals to the same degrees of milkiness, we find that it approximately halves with each 10º rise in temperature.
Evaluation
As shown in my Graphs, I do have a few anomalies, which prove that I may have had a few problems when performing my experiment:
When measuring the amount of Acid in the measuring Cylinder, I always brought the Cylinder to my eye level, thus making the test unreliable and inaccurate. To make my experiment more accurate, I should put the measuring cylinder on a flat surface and see if it the correct amount.
Another problem I encountered was with the stop clock, which made the test very unfair as each time I started the experiment I kept pressing the wrong button, and by the time I got it right, the experiment had already turned cloudy. To make the experiment more accurate next time, I should let one partner do the timing, and let the other pour the hydrochloric acid into the beaker.
The test could have also been more accurate if I repeated the experiment a couple more times, thus getting a more accurate result or even by making the temperature go up by 2º, where I would have been able to see where exactly the Rate of Reaction begins to speed up and at what Temperature.
Also, a burette could have been used to measure the volume more accurately, to give a more precise volume. This test may have also been unfair due to the lack of accurate equipment.
Overall, I am pleased with my results and findings, and have a better knowledge of how a Reaction such as Sodium thiosulphate and Hydrochloric Acid can be affected by not just the surface area, a catalyst and the concentration, but also the temperature.
