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CHEMISTRY 1211KSection B-05Precision and Accuracy of MeasurementsHonor Code: 09/13/2013
I. DATASection A: When is a Gram a Gram?Mass of empty packet of sweetener: 0.253 g (± 0.002 g)Nominal mass of sweetener: 1 g Number of balance used: #1 Table 1: Mass of five different packets of sweetener weighed on balance number 1.Trial NoMass of sweetener in grams(±0.002 g)Percent error11.070 g7.290 %21.097 g7.110 %31.140 g6.842 %41.057 g6.149 %51.047 g5.253 %Average mass of sweetener in grams: gStandard deviation of five measurements: gTable 2:Mass of one packet of sweetener weighed on five different balances.Balance NoMass of sweetener in grams(±0.002 g)Percent error11.029 g3.596 %21.030 g3.689 %31.029 g3.596 %41.029 g3.596 %51.025 g3.220 %Average mass of sweetener in grams: g
Standard deviation of five measurements: gSection B: Measuring LiquidsVolume (mL)Smallest Graduation (mL)Estimated Precision (mL)25 0.5± 0.01100 1 ± 0.1100010± 0.1 Table 3: Precision of 25, 100 and 1000 mL graduated cylinders.Table 4: Mass of 10 mL of water delivered by a 10 mL graduated cylindered.Theoretical Volume (mL)Total mass measurement (g)Calculated mass of added water (g)Calculated V10116.4289.7109.7320126.08519.42019.430 135.70829.04329.1Average volume delivered by a 10 mL graduated cylinder: mLStandard deviation of measurements: mLTable 5: Mass of 10 mL of water delivered by a 10 mL serological pipette.Theoretical Volume (mL)(±0.06 mL)Total mass measurement (g)(±0.002 g)Calculated mass of added water (g)Calculated V10 116.428 9.763 9.720 126.014 19.34919.330 135.644 28.979 29.0Average volume delivered by a 10 mL serological pipette: mLStandard deviation of measurements: mLRoom Temperature: 21.5oC
Density of water: 1.000 kg/mLTable 6:Mass of 10 mL of water delivered by a 10 mL Grade A volumetric pipette.