The Effect of Temperature and Concentration on the Rate

Evaluation Like each(prenominal) experiment, there were a number of potential misunderstandings during the procedure of the experiment. Errors could necessitate arisen as a result of the uncertainties associated with the actors I utilise to take measurings, and excessively as a result of errors associated with the actual method. Of course, due to the limitations of the procedure, they could non be eliminated completely, so I will explain what I did to tighten them to an acceptable direct and how I could eat up improved my method to reduce them even stunned further. Equipment justificationThe hobby table shows the reasons for my choice of equipment in carrying out my method. Equipment Justification coke cm3 buret I requisite to accu orderly measure out large quantities of total heat hydrogen peroxide (90 cm3 and 150 cm3). The 100 cm3 burette is a precise instrument and would allow me to measure out the hydrogen peroxide by choice it fewer measure than I would need to with 50 cm3 burette. 50 cm3 burette I needful to repeatedly measure out small glitzs of solutions AI. The burette do the task convenient, and it is a precise instrument. 250 cm3 volumetricalal flaskful I needed to make up a specific volume of a standard solution. The volumetric flask has a low error. 100 cm3 volumetric flask I needed to make up a specific volume of a standard solution. The volumetric flask has a low error. Top pan counterweight I needed to accurately weigh out small tot ups of solid when fashioning up my solutions. 25 cm3 Mohr pipet I utilize the pipet to accurately transfer sulfuric acid when making up solutions. I could non do this with a volumetric pipette, as the volume I transferred was 20 cm3. Distilled pee I personad the distilled water to wash out any glassware and store jars before employ them to avoid contamination. Crushed ice I used the ice to cool my reactants bolt down to 10 C. Water bath I used the water bath to heat my reacta nts up to 30 C, 40 C and 50 C. It kept the temperature constantit does not cool down like hot water in a beaker. Thermometer I needed to measure the temperature of the reactants before move them into the beaker and stirring them. Magnetic stirrer I used the stirrer to ensure the response mixture was uniformly mixed.This was undeniable to produce sharp gloss deviates. Stopwatch I used the stop watch to record the time of the colour changes. These are the values I needed to investigate the effect of temperature and assiduousness on rate. Measurement errors These are the errors associated with the equipment I used when weighing out solids, measuring volumes of liquid, recording the temperature of my reactants, and recording the times of the colour changes. Equipment Error 100 cm3 burette 0. 2 cm3 50 cm3 burette 0. 1 cm3 250 cm3 volumetric flask 0. 3 cm3 00 cm3 volumetric flask 0. 2 cm3 25 cm3 Mohr pipette 0. 1 cm3 Top pan balance 0. 005 g Thermometer 0. 5 C Stopwatch 0. 005 s (for instrument), 0. 5 s (for measurements), 0. 05 s (for measurements at 50 C) The stopwatch could record to 2 d. p. but the times I recorded were affected by my reply time. Recording to 2 d. p. would be pointless, as I could not record that precisely. I heady to record the times to the nearest second, except for my results at 50 C, where I recorded them to 1 d. p. because of the short duration of time between the colour changes.Percentage uncertainties Using the measurement errors, I can work out the great deal uncertainties for my measurements. I can do this using the formula percentage hesitancy = error / value of measurement x 100% I made multiple measurements with many of the instruments I used. For these measurements, I will find the uncertainties for terzetto of the values (the highest, the lowest and one close to the average) to give an indication of how the disbelief changed across the range of measurements I made. Equipment Error Measurement Percentage scruple / % 100 cm3 burette 0. cm3 150 cm3 (I used the burette twice, so 0. 4 / 150 =) 0. 27 90 cm3 0. 22 50 cm3 burette 0. 1 cm3 10. 00 cm3 1. 0 5. 00 cm3 2. 0 1. 00 cm3 10 250 cm3 volumetric flask 0. 3 cm3 250 cm3 0. 12 100 cm3 volumetric flask 0. 2 cm3 100 cm3 0. 20 25 cm3 Mohr pipette 0. 1 cm3 20 cm3 0. 50 Top pan balance 0. 005 g 26. 75 g 0. 02 10. 7 g 0. 05 0. 85 g 0. 59 Thermometer 0. 5 C 50 C 1. 0 30 C 1. 7 10 C 5. 0 Stopwatch 0. 5 s 437 s 0. 11 95 s 0. 53 1 s 50 0. 05 s (at 50 C) 31. 8 s 0. 57 12. 9 s 0. 388 1. 5 s 3. 3 The percentage uncertainties vary wildly depending on the error of the instrument and the value of the measurement. The largest uncertainty (50%) came from the stopwatch when I used it to record a time of 1 s. However, this would not have affected my calculations to a great extent, as I precisely used the time to calculate the blue cycle for the first hertz. It would not have affected the value I calculated for the average oscillation perio d by a significant amount, and would not have observably affected the slues in my graphs.This applies to all uncertainties from the stopwatch. I could have recorded all my times to 1 d. p. to improve the accuracy of my calculations and d stabbing graphs that showed a trend closer to the true one. The second most significant uncertainty (10%) was for the burette when I used it to add 1 cm3 of solution to opposite ladder tubes in order to probe the effect of changing the niggardness of propanedioic acid, manganese(II) sulfate(VI) and sulfuric acid. This is a very significant error that could have definitely weaken the accuracy of my results.It might explain, for instance, the wildly varying number of oscillations I observe for runnels at 0. 01 M manganese(II) sulfate(VI), as well as the increased way of senseless results at lower soaking ups. Even the uncertainty for a measurement of 10 cm3 using the burette was 1%, which is significant. In order to reduce the instrumental error, I could have used a 1 cm3 pipette or syringe to measure very small volumes of solution. I could not have done much more(prenominal) to conveniently transfer large volumes of solution (i. e. p to 10 cm3) piece reducing the error, as even a 10 cm3 pipette has the same error as a 50 cm3 burette, and it would have been extremely time-consuming to transfer my solutions to test tubes using a 1 cm3 pipette. Still, a 1% uncertainty would not have dramatically affected my results. Another source of significant percentage uncertainties was the thermometerat every temperature the uncertainty was above 1%. At 10 C, it was 5%, which is particularly significant. This means that I could have started stirring the reactants at a temperature between 9. 5 C and 10. 5 C.However, there were no thermometers more precise than 0. 5 C, so there is not much I could have done to reduce this error. Anyway, looking back at my raw results, the times I recorded for tests at 10 C were not particularly di scordant in comparison with the results I obtained for the other temperatures. only other errors were below 1%, so were insignificant. I used the volumetric flasks castigately, using a Pasteur pipette to add the distilled water for the last cm below the graduation mark, checking the mark at eye level in order to make sure I stopped at the correct point.I took readings from the bottom of the meniscus at eye level when using the Mohr pipette and burettes to reduce parallax error. I had to round up the mass of manganese(II) sulfate(VI)-1-water I weighed on the top pan balance from 0. 845 g to 0. 85, so an 4 d. p. analytical balance would have been better for this, but I did not have access to one. Procedural errors These are the errors that could have arisen from the method and improper technique. When making up solutions, it is important to rinse out the glassware and other equipment with distilled water before use.This was particularly vital for the BR reaction, due to its high e sthesia to chloride ions. As mentioned in my method, I did wash out all equipment with slightly distilled water before putting them in contact with any reactants to minimize the risk of contamination. It would have been impossible to prevent a small amount of solution from being lost when transferring them. When transferring from a beaker through a funnel to volumetric flask, the small amount go away would have led to a lower final concentration indeed planned. I minimised this error by washing out the beaker with distilled water three times.When pouring solution from the test tubes into the reaction beaker, a small amount is also lost. However, the amount left would have little effect on the results because it is a systematic error, i. e. it is repeated every time the solution is poured. I always inverted the volumetric flasks when making up solutions in order to ensure homogeneity. Before pouring them into the burettes, I gave the storage bottles a swirl in case the consent of the solution had been affected during storage. This would prevent the trials from being tested at different concentrations, which would have compromised the accuracy of my results.In addition, I used a magnetic stirrer to make sure the consistency of the solution stayed even within the reaction beaker. This also meant that the colour changes were sharper. It was especially important that the blue colour change was sharp, as this is the value I used to calculate the oscillation period, and therefore, rate of reaction. However, because human reaction time is not perfect, there was always some delay between the colour change and the pressing of the stopwatch. This is why I could not record times accurate to 2 d. p.At higher temperatures, i. e. 40 C and 50 C, the water from the solutions in the test tubes evaporated a lot faster than at room temperature while being heated in water bath, which would have increased the concentrations of the reactants and overstated the effect of the temperature increase. I minimised this error by removing the test tubes from the water bath as soon as possible after the temperature of the reactants reached the appropriate level. beside time, I would seal the test tubes using stoppers to prevent any water vapour from escaping.Unfortunately, the reactants could not remain at their starting temperature while being stirred, as they had to be poured into a beaker and set on a magnetic stirrer. This means that during tests at 30 C, 40 C and 50 C, the reactants cooled down at 10 C, the reactants change up. This would have understated the effect of temperature on rate. There was a riddle with the hydrogen peroxide in the burette. Because it was stored in the fridge, it was cold when I took it out. As it warmed up, there were noticeable increases in the level of solution in the burette.Trials that were run near the start of the session may have used colder, more concentrated hydrogen peroxide, which would have affected the rate of rea ction. I only took the temperature of reactants when I tested the effect of temperature. In order to purport this problem next time, I would take out the hydrogen peroxide at the very start of the lesson and wait for it to warm up while setting up the other burettes, magnetic stirrer etc. and also take the temperature of the reactants when testing concentration to see if it might have had a secondary effect on the rate.The potassium iodate(V) was not soluble generous to make Solution F (potassium iodate(V), 0. 5 M). Although I did manage to in full dissolve it with the aid of heat, a small amount crystallised out of solution after it cooled down, which would have decreased the solutions concentration and affected the results I obtained for the tests where I changed the concentration of potassium iodate(V) and sulfuric acid. Next time, I would change the experiment and run the tests at lower concentrations. dependableness My results were quite reliable, as I ran the reaction thre e times at each temperature and concentration.The number of oscillations was usually the same at each temperature/concentration and the times were concordant to an acceptable degree. There were a few anomalous runs, which I mentioned in my analysis section, and gave a possible explanation for above. I could have repeated the experiment a further time when I got inconsistent results, e. g. 0. 01 M manganese(II) sulfate(VI), to increase reliability. Extending the investigation The observations I made around the colours during particular runs were solely soft.I could broaden the scope of my investigation by using colourimetry to obtain a quantitative measurement of the colour fervor when the reaction was especially faint or dark. I could then compare it to values from the standard reaction to reinforce my observations. I could also use the data logger to measure the times of the colour changes. I could then compare the results from this technique to those from the stopwatch and eva luate the advantages and disadvantages to both methods, and decide which one would be better at producing accurate results.Conclusion Overall, I am well-to-do that I have made valid conclusions about the effect of temperature and concentration on the rate of the BriggsRauscher reaction. Although I did not fully meet my steer of finding the order of reaction for every reactant, I did discover that the reaction was not typical in this sense, and that the orders of reaction could not easily be found. I did manage to justify parts of the mechanism through the qualitative observations I made.