Pipetting, weighing, accuracy and plotting
In this practical, there were three parts in which basic skills and key ideas were put into practice as they are essential to working in the laboratory in order to get reliable and valid results; one of the basic skills put into practice was pipetting. This was the main objective for the whole practical, as pipettors are the fundamental tools used to measure liquids in laboratories. Not only did this develop the skills and confidence acquired for using pipettes, but it also gave an idea for what pipette would be best to measure out specific volumes for part three of the practical, which entailed finding out the concentration of a salt in an unknown substance by finding its density and comparing it to the density of water which is 1Kg. It was believed that the mechanical pipettor was going to be more accurate than the serological pipettor as the mechanical pipettor is renowned for accurate liquid dispensing.
The first part of the experiment consisted of the use of a 1000 µl mechanical pipettor and a serological pipette to pipette 1000 µl of pure water into a weighing boat on the scales to gain a weight of 1000 grams. This was repeated 3 times to increase the chances of gaining reliable data. After gaining the data, the average and standard deviation for both pipettes were calculated. In the second part of the practical, a 100 µl pipettor was included in addition to the previous two pipettes used in the first part of the practical. With each pipette, 100 µl of pure water was again pipetted which was repeated three times to increase the reliability. After retrieving the data, the average and standard deviation for all three pipettes were calculated. In the third part of the practical, water was measured at different volumes using a pipette of choice. This was based on the understanding of which pipette would produce an accurate and precise measurement for the specific volumes. This was...
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