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The Effect Of Concentration Of The Reaction Between Sodium Thiosulphate And Hydrochloric Acid

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The Effect Of Concentration Of The Reaction Between Sodium Thiosulphate And Hydrochloric Acid Introduction For a chemical reaction to take place, particles have to collide with each other, and must collide hard enough to break the bonds within them so new substances are formed. Only a very small percentage of collisions result in a reaction. This is because there is an energy barrier to a reaction, and only those particles with enough energy to overcome the energy barrier will react when they collide. The minimum energy that a particle must have to overcome the energy barrier and react is called the activation energy. The size of this activation energy is different for different reactions. If the speed of chemical reactions is increased, the frequency of particles colliding and the force of the collision will also need to increase. In this experiment, there are four variables that can be taken into account, are: * Surface area, * Catalysts, * Light, * Temperature, or * Concentration. Rate of reaction= 1/T Surface area As the surface area increases, the rate of reaction increases. This is because the particles on the surface of a solid are able to react with the particles in the solution or a gas, therefore, the larger the surface area the more particles there are in contact with the gas or solution, and therefore the faster the reaction. If a solid is cut up into smaller pieces there is more surface area exposed, for example, here is a diagram showing ...read more.


* Hydrochloric acid * Sodium thiosulphate Method 1) Firstly, draw a black cross on a piece of white paper. Then place a beaker filled with 50cm� of sodium thiosulphate on top of the piece of paper, making sure the cross is easily seen through the solution. 2) Add 1 cm� of hydrochloric acid using a pipette, and start off by adding no water to the solution of sodium thiosulphate. 3) Start the stopwatch as soon as both the Hydrochloric acid and the sodium thiosuphate is added. At each interval, add 2 extra cm� of water. Swivel the mixture and time how long it takes for the cross to be completely obscured. His mixture should turn cloudy, if not yellow. 4) Then empty out the contents of the conical flask, clean it out, and dry it. Repeat this three times, and find an average result. Fair test In this experiment we are trying to find the rate of reaction using concentration as a factor, so there is a number of things we need to make sure we do to keep it a fair test. Firstly, we need to keep a chemical at a constant concentration. So, in this experiment we have chosen to keep Sodium thiosulphate and hydrochloric acid at a constant concentration. Next we must make sure that the solution is kept at a constant volume throughout the experiment. If the volume is different, then it could give different results to if it was at a constant volume. ...read more.


And by looking at my results on the graph I believe that my results do agree with my prediction. In conclusion to this experiment I find that my prediction was correct. Evaluation My results are accurate because when I read the collision theory it told me exactly what my results told me. The results I obtained from the experiment were accurate; this indicates that the experiment I preceded was successful. As I performed my experiment three times, the individual results were reasonably reliable excluding the first attempt that I did, as they were approximately I minute apart. This may result to an increase of the appropriate amount of sodium thiosulphate, hydrochloric acid and water added. I would also make my experiment a fair test, by making the results more accurate. I would do this by using clean equipment, and using the right amount of acids. From looking at the graph, I have noticed that there are two anomalies. The first was at the concentration of 16 g/cm, and the second anomaly was at the concentration of 32 g/cm. There are many reasons towards this, first of all, the experiment may have not been a fair test, simply because I may have not cleaned out the flask, or, the amount of acid may have varied according to what is was suppose to be. If I were to do the experiment once again, I would take into consideration the amount of sodium thiosulphate used, by using more acid; the whole experiment will take less time to do. An investigation into Rates of Reaction Roopal Dhanota ...read more.

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