Increased Concentration example essay topic

. Experiment for Chemistry Coursework For this investigation I am looking at how the concentration of acid can change the reaction and how I can explain this using collision theory. My Prediction: I predict that the greater amount of concentration the faster the reaction will take place. Therefore, particles in the two compounds will collide faster. Due to my prediction if it is correct, I expect to see the cross on the paper disappear faster. As I already know that increasing one quantity will speed up the reaction as the particles are more likely to collide. In this investigation several measures will need to be done to make sure that the results I get will be precise.

From the planed method I can work out what will need to be done to achieve the best results possible. I will also need to think about what other factors may vary my results to someone else's and how this could be improved. Equipment Needed: . Beaker. Test-tube.

Piece of paper with a cross on. 25 ml^2 of Sodium Phiosulphate. 5 ml^2 of Hydrochloric Acid Factors about the equipment that may affect the results: The amount of one particular quantity, or concentration of the acid. The type of acid that was used may either slow down or speed up the reaction. Also, another factor maybe that the time it take until I begin to start the stopwatch.

To control the problem of affecting results I would have to swirl the mixture for e.g. : every 2 seconds. However, this would have to be done in every type of concentration and experiment. Diagram of method: Method: Draw a cross on a piece of paper and place a beaker on top of the paper. This is because once the cross disappears I know the reaction has completed as the compounds have now become one solution. Secondly, measure as accurately as possible 25 ml^2 of Sodium Phiosulphate and 5 ml^2 of Hydrochloric acid.

Thirdly, pour the measured amount of Sodium Phiosulphate into the beaker and then add the Hydrochloric acid. Once this is added start the timer. Finally, once the cross has completely disappeared stop the clock and make a not of the time it took for the mixture to become one. NOTE: This procedure was produced with different concentrations. This was so that I could see whether the concentration had an affect on experiment's time limit.

Results: Before doing our experiment we saw a trail run on the computer known as: MULTIMEDIA SCIENCE SCHOOLS From the computers experiment I found results I would know what to expect when I would do my experiment. I learnt how different quantities and temperature can affect the speed of collision with in the particles. From the experiment we had a set of results these were: I looked at other groups results to see to see if their results corresponded to mine: Limiting Factors: The time it took till the clock was started and the difference between when "we" thought the cross was no longer visible. Other Factors that may have affected our results: The following may have affected our experiment in one way. This may have been the cause for any anomalous results. These included: The amount of hydrochloric acid measured incorrect, the amount of Sodium Phiosulphate measured incorrectly, size of the cross, any movement of the beaker, time taken until we began starting the stop clock.

From the table of results I can tell that the increase of concentration will affect the time it takes for the particles to collide with each other. I know that the increased temperature increases the rate of reaction; therefore there is an increase in the particles colliding. However, I do not know the ultimate rate that particles can collide. Taking an average would be one possible way in which I could estimate this. Looking at the graphs and how each set of results corresponds to one and other: The computers Results: Even thought the quantities measured in arbitrary units this does not mean it will not show an increase or decrease in the rate of collision.

From this I can see that the concentration and temperature affects the collision of particles. As the concentration increased so did the collisions, even with just moving the concentration one arbitrary unit up. Our Results: The graph shows that the increased concentration and increased movement of moving the beaker had an affect on the rate of reaction. This was due to there being more particles of one specific substance so it was more likely for the increased solution to collide with the decreased one. The concentration carried on being increased until there were enough results to show a trend or pattern. This shows that the fastest reaction was dependant on temperature or a big difference in particle numbers.

Group 1's results: Group one also shows a decrease in time as the concentration was increased. However, after a certain while it maybe that there are only so fast the particles can collide. I believe that at this stage the particles were near its fullest rate of colliding, as the results seemed to almost form a decreasing line as the concentration decreased. Evaluating Results and improving initial ideas: Temperature: Throughout the experiment we did not measure the temperature. If the temperature was to increase I believe that the reaction would happen faster. I think this as I already know that heat speeds up atom collision.

Therefore, the process of particle collision would increase. Results: The results I found did have a trend and pattern. From this I came up with certain amounts of facts that would help me when investigating further into collision theory. The experiment ran well and I believe that considering the certain effects it would not have been able to run much better.

Improving: To improve the experiment I would use a varied amount of temperature, light intensity, and different types of compounds. Reliability: The experiment may not have been totally reliable. This could be due to the amount of time we had between mixing the solutions and timing the reaction. Also, the highest rate of collision maybe be different at different times depending on the temperature. As the temperature was not checked through out the experiment it is hard to say whether this would affect the experiment. However, I do know that heat speeds up the rate of which particles react, so this maybe taken into account.

Anamolous Results: Both groups had some results. This maybe because the groups were unsure when the cross had fully disappeared. Also, the amount of solutions may have been measured incorrectly, as it is hard to measure accurately. However, judging on these ideas is tenuous as there maybe more improvements to be done to this experiment as previously.