The rate of rReaction Essay Example for Free

The rate of rReaction Essay These results also support my prediction and I believe that the collision theory is quite accurate even though it is only a theory as it gives a very good explanation of what should happen and it has happened in my experiment. I am going to include 0. 25M in my main experiment as I believe that this will give a better range of results and also increase the accuracy of my results. I will keep the amount of time the same as I believe it was the best amount of time to get an accurate reading. I will do my main experiment results to one decimal place as I believe that this will give me the most precise results. When reading the amount of gas in the cylinder I will take any number that is whole e. g. 14 to be 14. 0. To improve my reliability I will repeat each concentration three times as I believe this will give me a reliable average. Results Table Results To Show How Much Gas Is Given Off In 5 Minutes Volume of Gas Collected (cm ) Time in minutes Test Concentration Test Any number highlighted are not counted in the average as I believe that the are either to high, to low or do not fit into the pattern. Result that I believe is causing the results for this time to be inaccurate. ( see level of confidence) I will not include this result in my new average. I have found out that 2M is the best strength of hydrochloric acid to use when you want a fast reaction, as it released the most gas in 5 minutes compared to 0.5M, 1M and 1. 5M. I can make the statement the stronger/higher molar(M) the acid the faster the reaction and the weaker/lower molar(M) the acid the slower the reaction. Conclusion I conclude 2M is the best concentration of acid. You can see this on my graph, my graph shows that 2M is the best concentration of acid out of all the ones that I tested as it had the quickest reaction time compared to all of the other concentrations. You can see this from the graph as 2M has got the steepest slope. I believe that the activation energy (see background information for detailed explanation) has effected my results. I believe that the concentration of the acid makes it easier for the particles to react. But what does this have to do with the activation energy? Each molecule has a certain amount of energy and for the molecule to react it must collide with another molecule. It must also generate more energy that it already has. In a low concentrated solution, there are less molecules so it hard for a molecule to find other molecules to collide with, but in a high concentrated solution collisions are more frequent and even if the molecule does not collide with enough energy to react it will soon hit another molecule and have a high possibility of reacting. I predicted that the 2. 0 molar acid would have the quickest reaction time and the 0. 25 molar would have the slowest reaction time I also said that the other concentrations would go in order of their concentrations, the higher the concentration the more gas there will be released and the lower the concentration the less gas there will be released. I believe my predictions were accurate as I based them on the collision theory and even though it is a theory I believe it is an accurate theory and explains what is believed to happen when reactions take place very well. 0. 5M and 1M start off wrong in my opinion as until 3 minutes 0. 5M had released more gas where as I believe according to the collision theory 1M should have released more gas and reacted faster, but in the end 1M released more gas. This also happened in the first 30 seconds of the 0. 25M where it also released more gas than the 1M. This leads me to believe that the 1M may have been the wrong concentration. It is because of this reason I am going to work out the confidence levels for my results. I will take 0 as 100% accurate and 100 as 0% accurate. Level Of Confidence I am going to work out the inaccuracy of my results I will do this by doing the sum Range multiplied by 100= level of inaccuracy Average I have chosen to do the inaccuracy of time   as I believe that I can get a good reading of how inaccurate my results are by doing a selected number of times. Time Concentration Range of gas Average Amount of Times Equals (minutes) of acid(M) released(cm ) gas released(cm ). I am going to look at   my results table and 1 Level of confidence for sum that I believed was inaccurate I have now changed the range of the gas released at 4. 5 minutes.   This inaccuracy level is a lot lower than the other one. This means that that volume of gas released was to low, many things could have caused this . e. g. the temperature of the room could have been lower than when I did the other two experiments. Evaluation I believe my results are quite accurate and would be considered reliable as non of my results have a high inaccuracy level or have a 50% chance of being wrong. I have highlighted the results that I believe are wrong on my results table and have not included them in my averages. On my graph my points go up in curves or in some sort of curve. I have joined all of the point on my graph together but on some of my curves I have done a curve of best fit, I have done this because it will show me if any results are slightly wrong. If you look at the green curve for 0. 5M you will see that the points at 2 and 2. 5 minutes look slightly to high, the curve of best fit shows where the points should have been. The trend I see from the graph is that the higher the concentration of the hydrochloric acid the steeper the slop of the graph is. I believe that the way in which I carried out my experiment was good as I followed my method exactly. To improve the accuracy of my method I could have said I would use a bulb pipette or a graduate pipette as these are more accurate than a measuring cylinder, I could make sure that the marble chips all have the same surface area because the marble chips with the bigger surface areas could have reacted more than the marble chips with the smaller surface areas. I could have also make sure that the room was the same temperature for each experiment because if the room was hot for one experiment and cold for another then the results would be inaccurate as the molecules would have been moving and reacting at different speeds. The results I have support my conclusion and my prediction, as what I predicted would happen did happen. The order of the concentrations for the most gas released in 5 minutes was also accurate, as it was in the order that I predicted. To extend my investigation I could test if the temperature had any effect on the amount of gas released, I believe this would provide me with the relevant information about what the optimum temperature is for a reaction to take place. I could then test the optimum concentration and the optimum temperature together and see how much gas is released in 5 minutes and compare it to the separate results of the concentration and temperature. Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Patterns of Behaviour section.