Graph Of Reaction Rate Vs Concentration example essay topic

... person to person. For my big measurements of liquid I will use a large measuring cylinder. I will not introduce a catalyst to the experiment neither will I increase the temperature of the liquids by holding their containers too long, and I will keep the area's temperature in which I'm working in constant. To be on the safe side I will try to keep the light intensity the same throughout the entire experiment by working in the shade. Prediction: I predict that as concentration of increases so will reaction rate.

Concentration of a reactant affects reaction rate because there are more frequent successful collisions. Assume a person has two chemicals x and y, which react when put together. If all input variables remained constant apart from concentration then fastest reaction rate possible would be to mix (assuming there isn't an excess) x and y together in their purest forms. This is because every time an x molecule collides into a molecule it has a 50% chance of it being a y molecule.

But if you removed half of y and replaced it with a neutral chemical such as z the chances of a x molecule bumping into a foreign molecule decreases from 50% to about 25%. This in effect lowers reaction rate by lowering amount of "successful collisions" This means that as concentration of y decreases so does reaction rate. This could be true for x. The same theory applies with HCL acid and Thiosulphate, so as concentration increases so will reaction rate.

I believe that if you plotted percentage of against rate of reaction you would get a straight line, which also means that I predict that they are directionally proportional to each other. Percentage of reaction rate k (k being constant such as the input variables). As you can see only 2 Mg molecules can react with 2 HCL molecules. But if there was less water this happen: Now 4 molecules of Mg can react with 4 molecules of HCL.

The reaction would be quicker than the above because: What happens is that water molecules tend to get in the way of collisions, so if there are more water molecules in between two chemicals those two chemicals can't really get to each other, so really water tends to "clog up" the collisions like sawdust may clog up machinery. If you did plot reaction rate vs. concentration of and got a straight line when you plot Time (time taken for reaction to go cloudy) vs. Volume of Na 2 S 2 O 2 added you would get a downwards curve. I know this because I drew a hypothetical graph and then worked backwards to find out what the graph of reaction rate vs. concentration of and found out it would be a curve like the one explained above. HCL volume in cm 3 Volume of H 20, cm 3 Thiosulphate volume in cm 3 Time taken in seconds Rate of reaction (1/t)'s 10050320.03110545360. 028102030580.0171030201000. 0101040102100.004 Finalizing the method: In my results graph, specifically the percentage of vs. over reaction time is unsatisfactory.

This is because I do not have enough points to plot a graph and decide its line of best fit. More specifically I am unable to decide whether or not my graph's line of best fit is a curve or a straight line, I am justified in drawing both because of the quality of the graph. I intend on doing more tests in my next experiment by timing the reaction for 70% and 80% to determine if concentration is directly proportional or exponential to rate of reaction. I would also like to do a set of check readings.

I will not use my preliminary results in my final graph (as an average) because each experiment would be done on a different day. This is because room temperature may be different and so affecting my results. I think it would be quite suitable to test reaction rate at these different percentages of in solution, 83%, 75%, 50%, 33% and 16%, the rest being 16% HCL and if any left over it would be used up by water. HCL volume in cm 3 Volume of H 20, cm 3 Thiosulphate volume in cm 3 Time in seconds Time 1 Time 2 Average Time Rate of reaction (1/t)'s 100503236340.029105453628320.

0311020306356600.0161030209496950. 0101040102112132120.005 Analysis have found that as concentration of (one of the reactants) increases so does reaction rate. This is shown by my graph as a positive correlation between percentage of in solution and reaction rate (1/t in seconds). My prediction stated my prediction stated that as one increases so will the other, I also said when the results would be plotted I may get a straight line; meaning they are directly proportional. This is supported by my results graph because it shows a positive correlation between in solution and reaction rate (1/t in seconds), and it is a straight line meaning they are directly proportional. The reason for this correlation is so: Concentration of a reactant affects reaction rate because there are more frequent successful collisions.

This is consistent with my results and is shown in my graph labeled Reaction rate vs. Percentage of in solution. Evaluating Because of staring at the black cross for too long it burnt the after image in my retina, a bit like a bright bulb, so I only realized it had gone perhaps a little too late, maybe 5 seconds. I think the fact that my head wasn't always at the same level when observing the. I think this had a relevant bearing on my results, but not enough to render them unusable; this was because of check readings, and the fact that that my head would have only differed in height by about 10 cm. When looking at my graph I don't see any anomalous results because they are all very close to my line of best fit, and my method is quite reliable as shall be explained later. I think the method could have been changed to a far more suitable one as seen below: During this set-up the room would be kept dark so as not to interfere with the LDR.

The light would shine through the reactants onto the LDR. As the test goes on less light would fall on the LDR, decreasing the resistance through the component. This should be quite noticeable on the voltmeter which would be set on an appropriate level found whilst doing preliminary, at a chosen resistance the person may stop timing. This method would be a lot more accurate than the as it takes out human error by itself judging when you should timing. I think I read my measurements to a good degree of accuracy because I made sure I used the right sized measuring cylinder for each liquid, so I had a small scale for small amounts etc. etc. I also made sure I was level with meniscus whilst measuring amounts of liquid.

I think my results are reliable enough to support a firm conclusion because my method was quite accurate, and how I performed the experiment was excellent; I got the same results in my preliminary and my final set. And if my method was inaccurate it would have been the same inaccuracy for all separate tests mean I don't really agree that my method needs criticizing or moderating seeing as it was accurate enough for my level of work, if I were a scientist and I had access to better apparatus I may moderate or criticize my method in the following way: I don't think there was a large enough range of results taken, it would have been useful (when plotted) to test reaction rate whilst varying concentration of HCL. It would be interesting to see if it showed the same pattern of results as my did. If there was a larger range of results then I could have thoroughly observed and different patterns to ones I got. Perhaps I should have got a meter rule and made sure my head was always at the same height, this is because as your height increases away from the beaker the cross becomes less visible, which means you stop timing a little earlier.