Errors Random and systematic errors are both factors that can affect the reliability and accuracy of the results respectively. As all the graphs contained outliers, and hence, scatter, this indicates that random errors were present. Such errors may result from the inconsistent masses of the Alka Seltzer tablets. As these tablets were cut manually with a knife, it is unlikely that the mass of each half of an Alka Seltzer tablet would be the same. Thus, when using the tablets to react with HCl, the true number of tablets reacting would have not been the same as the number denoted for the trial, and with each repeated trial for the same number of tablets reacting, the reacting mass and ratio would have not been inconsistent. Consequently, the …show more content…
Random errors reflect a low precision through high scatter. Increasing the sample size of the number of tablets used will produce more data that can be graphed, and from which a more reliable and representative line of best fit could be produced, ultimately minimising random errors. Additionally, increasing the number of trials for each number of reacting Alka Seltzer tablets would minimise random errors by helping to produce a more precise average change in mass. Modifying the method can also help minimise the effect of random errors, by obtaining more reliable results. For example, instead of cutting the Alka Seltzer tablets in half, whole Alka Seltzer tablets could have been used, and the amount of reacting HCl could have been increased to account for the increase in the number of tablets used for each ample. In doing this, the mass of the reacting Alka Seltzer tablets will be more consistent for each trial, and the state of subdivision of the tablets could be truly kept …show more content…
In undertaking the experiment, the hypothesis “if the number of Alka Seltzer tablets reacted increases, then the maximum rate of reaction will increase,” was formed. When graphing the relationship between the maximum rate of reaction and the number of Alka Seltzer tablets reacting, Graph 7 produced a line of best fit with a constant increasing slope that passed through the origin (0,0). This is characteristic of linear graphs, which have the general equation, y=mx, where m is the slope, a constant term, and y and x are changing variables that are directly proportional (i.e. y ∝x). Hence, it can be deduced that Graph 7 is a linear graph, and that there is a linear relationship between the maximum rate of reaction and the number of Alka Seltzer tablets, where they are directly proportional. That is, as the number of Alka Seltzer tablets increased, the maximum rate of reaction increased, supporting the hypothesis. As the true value of the maximum rate of reaction per Alka Seltzer tablet was not known, and a value for comparison was unavailable, the accuracy of the results could not be determined. However, due to the scatter in Graphs 2 to 7, it was evident that the results had low precision. In future, repeating the experiment using different and/or new apparatus will aid in detecting systematic errors and improve the accuracy and validity of the results.
Extraction is a separation method that is often used in the laboratory to separate one or more components from a mixture. Sucrose was separated at the beginning because it is the most immiscible and it’s strongly insoluble. Next Acetylsalicylic Acid was separated which left Acetanilide alone. Variety steps could have led to errors occurring. For example the step of separation, when dichloromethane layer was supposed to be drained out, it could be possible some aqueous layer was drained with it. Which could make the end result not as accurate. Also errors could have occurred if possibly some dichloromethane was not drained out. Both way could interfere with end result of figuring the amount of each component in the mixture. The solids percentage were 22.1% more than the original. That suggests that solids weren’t separated completely which clarifies the reason the melting points that were recorded were a slightly lower than the actual component’s melting point. The melting point for Acetylsalicylic Acid is 136 C but that range that was recorded during the experiment was around 105 C to 118 C. The melting points were slightly lower than the literature value. Sucrose was the purest among all component due to its higher melting point which follows the chemical rule that the higher the melting point the more pure the component
To keep this constant you have to buy the same kind of Alka-Seltzer tablet. Each of the Alka-Seltzer tablets might have a different kind of reaction for example one might contain more citric acid or might contain less aspirin. Additionally, another constant would be the type of water of used. You could use tap water or drinking water, they both have different properties for example tap water has many things added while normal drinking water lack those. If you use two different kinds of water then your data might be inconsistent and you want reliable data.
* It was almost impossible to tell when the Alka-Seltzer tablet had dissolved, each time the experiment was done. This was a huge problem for the experiment as this could have totally caused problems to the experiment. A special type of detector apparatus, which bleeped when the correct amount of Alka-Seltzer tablet dissolved, could improve this, each time the experiment was done.
The sand is If the water with Alka-Seltzer tablets is stirred during the reaction, then the rates of reactions will increase because the particles will be forced to make contact with each other and... ... middle of paper ... ...results anomalies because they are the outcome of dissociation of calcium and magnesium ions,. Evaluation: What is the difference between My results were very reliable, because by looking at my graphs I can see a trend that relates to my scientific background. It is also evident that I have obtained a reliable set of results when I see that.
A random error is caused by any factor which randomly affects the amount of scatter in the data. An increase in sample size allows averages to be calculated which reduces the effects of these random errors. By removing outliers in the data, the effect of random errors can be further minimised. A large amount of scatter in results indicated low precision and a large number of random errors. Some possible random errors in this experiment may have arisen when measuring the 12mL of milk solution for each test tube; some may have had slightly more and others slightly less than 12mL. Another random error could have occurred when adding 4 drops of methylene blue, some drops may have contained more liquid than others, meaning some test tubes may have contained less methylene blue indicator than
In this experiment, there were several objectives. First, this lab was designed to determine the difference, if any, between the densities of Coke and Diet Coke. It was designed to evaluate the accuracy and precision of several lab equipment measurements. This lab was also designed to be an introduction to the LabQuest Data and the Logger Pro data analysis database. Random, systematic, and gross errors are errors made during experiments that can have significant effects to the results. Random errors do not really have a specific cause, but still causes a few of the measurements to either be a little high or a little low. Systematic errors occur when there are limitations or mistakes on lab equipment or lab procedures. These kinds of errors cause measurements to be either be always high or always low. The last kind of error is gross errors. Gross errors occur when machines or equipment fail completely. However, gross errors usually occur due to a personal mistake. For this experiment, the number of significant figures is very important and depends on the equipment being used. When using the volumetric pipette and burette, the measurements are rounded to the hundredth place while in a graduated cylinder, it is rounded to the tenth place.
Possible sources of error in this experiment include the inaccuracy of measurements, as correct measurements are vital for the experiment.
Discussion: The percent of errors is 59.62%. Several errors could have happened during the experiment. Weak techniques may occur.
One possible source of experimental error could be not having a solid measurement of magnesium hydroxide nor citric acid. This is because we were told to measure out between 5.6g-5.8g for magnesium hydroxide and 14g-21g for citric acid. If accuracy measures how closely a measured value is to the accepted value and or true value, then accuracy may not have been an aspect that was achieved in this lab. Therefore, not having a solid precise measurement and accurate measurement was another source of experimental error.
The spreadsheet from the eLearn titled “Experiment I data” was downloaded to the computer. There were three inhibitors data given. The slope (V0) was calculated for each inhibitor data using the time versus response. The formula used to calculate slope was typed = slope (B6:B11, $A$6: $A$11) in the cell right below the last Reponses, and then from that cell dragged horizontally to get the rest of the slope. This step was repeated for Inhibitor 2, and 3 data.
...ore reliable if it were possible to do more trials to make sure that the data that was found was correct. This experiment could’ve been more reliable if some mistakes weren’t made like, the inaccuracy of weighing and measuring the potatoes. This could have affected the results by throwing off all the data and giving numbers that were nowhere near accurate. Another mistake that could’ve been made was the amount of solution put into each test tube. Some of the test tubes may have had to little or not enough of its solution. Some ways to fix both of these problems would be to weigh and measure each potato core more than once which is not what was done. A way to fix the inaccuracy of the amount of salt water put into each test tube would be to measure the solutions into a different container to make sure it’s an accurate measurement, then pouring it into the test tube.
...in size as a replacement for straw bits. As the data shows, some the proportion of marked straw bits in the first capture to the total population (n1/N) is not equal to the proportion of marked straw bits in the second capture to the total straw bits in the second capture (m2/n2). For example, 20(n1)/100(N)≠3 (m2 in the 4th trial)/10(n2). Since this is a random sampling, it is impossible to control the results especially the number of marked straw bits in the second capture. The container for straw bits is shaken for the mixing between marked straw bits and unmarked straw bits. However, it is not sure that whether the population is mixed thoroughly or not. Some marked straw bits may stuck in some corners with other straw bits even after the mix. Again this is a process of random sampling and it is unpreventable for the marked straw bits’ inability to mix thoroughly.
...s recorded. The procedure was repeated again for the same contorted sample and continued until we had recorded three chromatograms. We repeated the steps for each of the remaining standard samples, going from the most concentrated to the least concentrated, rinsing the syringe out a few times with the methanol/water mixture when changing to a caffeine sample of different concentration. Three chromatograms were recorded of each standard (ChemWiki). From the resulting chromatograms, measurements of retention time and peak areas were made. We used the area of all standard peaks to produce a calibration curve. Then using the calibration curve, we could determine the concentration of caffeine in each of the diluted samples. After determining the concentration of caffeine in the diluted samples, we could calculate the concentration of caffeine in the original sample.
Overall I think I carried out the experiment in a precise way and I took my time trying to make all my measurements as accurate as possible so that my data is reliable. Next time I will do more tests instead of just 3 so I have more results and so I could get a more accurate average. I will also do the experiment with more fruit juices to see if there are other fruits with a higher content of vitamin C. I will do an experiment to see if there is a difference in Vitamin C levels between fresh juice and store bought juice. I can also test different brands of juice to see if they have different levels of vitamin C.
There is also the potential of human error within this experiment for example finding the meniscus is important to get an accurate amount using the graduated pipettes and burettes. There is a possibility that at one point in the experiment a chemical was measured inaccurately affecting the results. To resolve this, the experiment should have been repeated three times.