# Being somewhat difficult to use efficiently they were

• Lab Report
• 9
• 100% (5) 5 out of 5 people found this document helpful

This preview shows page 7 - 9 out of 9 pages.

being somewhat difficult to use efficiently, they were still much more precise than any beaker or graduated cylinder. If students were not precise when collecting the solutions, they would have ended up with inaccurate data. Each volumetric pipette was also designated towards one specific solution, as cross contamination would have also resulted in faulty data. This showed how important precision was to the experiment, as even having dry pipettes make contact with another solution would have greatly skewed results and data. As for accuracy, there were no set KIN values or absorption constants to reference back to, thus the only way to determine how accurate a value was, is to wait until the results are marked. However, comparing the relationshipbetween a solution’s absorption and concentration should provide an idea of how accurate one’s values were, as the relationship should be as close to linear as possible.One error that could have occurred is cross contamination with the lab equipment. Cross contamination with stock solutions would have been reported to the TA immediately, to ensure other students do not end up with faulty data, however, contaminations that arose while mixing solutions would have resulted in faulty data at the hands of the student. In this experiment, a few contamination cases actually occurred with the stock solutions during the experiment. The absorption spectrum for solution B3 was also not recorded due to carelessness. As a result, data
had to be borrowed from another student, Shu Jie Li, to perform the necessary calculations. All errors were completely preventable if more attention was directed towards the experiment.
Discuss whether the Beer-Lambert Law is an accurate representation of experimental data? In what scenarios would the Beer-Lambert Law fail to provide accurate data and is there a way to correct for this?The Beer-Lambert Law describes the relationship between, the absorbance of light in a solution and its concentration. Generally, the law provides an accurate representation of experimental data, given two assumptions; the solution’s absorbance is directly proportional to its concentration and the length the light travels.[2]If these two conditions are not met, certain situations arise that cause deviations in achieving accurate data. One situation that causes inaccurate data is if the solution is of too high or low concentration.[2][3]This causes the molecules in the solution to behave in a way that interferes with the absorption, as the amount of light absorbed is dependent on the molecules it can interact with.[2][3]One way to resolve this issue is to either increase or decrease the concentration of the solution accordingly, or to use the modified version of the Beer-Lambert Law formula: A=εlc(η2+ 2)2.[3]Inaccurate data can also