Date of publication: 2017-07-08 16:27
I will make sure I handle the sodium thiosulphate solution and hydrochloric acid with care. I will also be careful when heating up the solutions and will at all times wear safety goggles and also remain standing throughout the experiment. Furthermore I will be careful not to spill anything and will take extra care when doing the experiment.
It is obvious that there is a general trend in the results. As the temperature increases, the time taken for the sodium thiosulphate solution to become cloudy decreases. This is because as the temperature increases, the reactant particles move more quickly. In addition to this, more particles have activation energy. This means more of the particles collide and more of the collisions result in a reaction, so the rate of reaction increases.
A piece of cotton wool is placed in the neck of the flask to allow carbon dioxide gas to escape. As the gas escapes the mass of the flask reduces. Take readings of mass loss over a time interval, . 85 seconds.
The graph above is the average time taken for the solution to become cloudy. It also has a line of best fit to show the consistency and accuracy of the results. There are no anomalous results which shows that the experiment was very accurate. Furthermore, the graph is a perfect curve
To measure the hydrogen gas released in the above reaction we use the apparatus as shown. As the bubbles of gas are given off, the plunger in the syringe moves out as hydrogen gas fills it. After, say every 75 seconds we read the volume of gas in the syringe. The reaction is complete when the syringe no longer moves.
The quality of my evidence is good. There were no points on my scatter graph that were not on or close to the line of best fit. The range of my results were also suitable to make good observations and conclusions
I predict that the greater the temperature of the sodium thiosulphate the faster the solution will become cloudy. This is because the greater the temperature, the faster the particles will move, therefore increasing the amount of collisions and successful collisions taking place. Similarly, when the temperature is decreased there will be less energy, so there will be less collisions and successful collisions taking place so the rate reaction will decrease. From my preliminary results I have come up with a theory that for every 65 ° C of temperature increased, the time taken for the cross to disappear is roughly decreased by half, but only in some cases.