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CHEMISTRY POST-LAB FOR EXPERIMENT 1 Charlotte Steininger – 902616356 Lab Section A1 A. BALANCE: WHEN IS A GRAM, A GRAM? 1. The precision of a manufacture when putting 1.0 g of sugar into each packet is relatively consistent, but there is an average standard deviation of around .0659 g. This indicates that within a sample of multiple packets, each one will have a varying weight due to the deviation of the precision. Accuracy is not incredibly reliable because an average percent error of 9.58% was calculated when all of the actual values were compared to the measured values. This lack of accuracy may be accounted for in the experimenter’s inability to sustain the use of the same balance for each measurement. If the manufacturer had stated that each packet contained 1.000 g, there would be less consistent precision because the variability would be +- .002 as opposed to +- .2, but the accuracy would be much more reliable. 2. Exercise A-3 makes it apparent to the experimenter that it is necessary to use the same balance or scale throughout an experiment in order to achieve minimal deviation and optimal precision. Accuracy, however, remains unreliable, obtaining a percent error of 17.7%. This inaccuracy does not have much to do with the balance itself, but more to do with the manufactures’ inaccuracy. In order to distinguish this difference in accuracy, it is also necessary to consistently use the same balance during an experiment. B. MEASURING LIQUIDS 1. The 10 mL volumetric pipet, which has a precision of +-.02, is theoretically supposed to deliver the most precise and accurate results, while the serological pipet has a tolerance of +- .06 and the 10 mL graduated cylinder has a tolerance of +-.05. In this specific experimentation pertaining to the measurement of liquids, none of the glassware delivered results were directly correspondent to that of their
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