Original Hypothesis: Prior to performing any measurements or calculations in the lab, it was originally hypothesized that the 10 mL volumetric pipette would be the most precise and most accurate instrument, while the 10mL graduated cylinder would be the least precise and least accurate instrument.
Sample Calculation: For the 10 mL volumetric pipette, three weight of water measurements were taken by first weighing a beaker on the scale, measuring 10 mL of water with a volumetric pipette, putting the measured amount of water into the beaker, and then reweighing the beaker. Next, the weight of water was calculated by subtracting the weight of the empty beaker from the weight of the beaker containing water. These values were then converted to water volume using the density of water at a temperature of 19.5 °C; 0.998 g/ml. The weight of water measurements, 9.82 g, 9.90 g, and 9.94 g, were converted to water volume by dividing by 0.998 g/ml as shown below. Volume = (9.82 g) / (0.998 g/mL) = 9.84 mL Volume = (9.90 g) / (0.998 g/mL) = 9.92 mL Volume = (9.94 g) / (0.998 g/mL) = 9.96 mL
The average water volume was then calculated by averaging the three obtained water volumes. Average Volume = (9.48 mL + 9.92 mL + 9.96 mL) 3 = 9.91 mL
Discussion:
Instruments that are both precise and accurate provide the best …show more content…
The average water volume calculated for the burette was 10.029 mL, which is 0.029 mL from the actual water volume of 10mL. Because, 0.029 mL was the smallest difference from the actual 10 mL, it is considered the most accurate piece of equipment. On the contrary, the least accurate instrument, the graduated cylinder, provided an average water volume of 9.672 mL, which is 0.328 mL from 10 mL, the largest difference presented from the three instrument
Sample Calculation: For the 10 mL volumetric pipette, three weight of water measurements were taken by first weighing a beaker on the scale, measuring 10 mL of water with a volumetric pipette, putting the measured amount of water into the beaker, and then reweighing the beaker. Next, the weight of water was calculated by subtracting the weight of the empty beaker from the weight of the beaker containing water. These values were then converted to water volume using the density of water at a temperature of 19.5 °C; 0.998 g/ml. The weight of water measurements, 9.82 g, 9.90 g, and 9.94 g, were converted to water volume by dividing by 0.998 g/ml as shown below. Volume = (9.82 g) / (0.998 g/mL) = 9.84 mL Volume = (9.90 g) / (0.998 g/mL) = 9.92 mL Volume = (9.94 g) / (0.998 g/mL) = 9.96 mL
The average water volume was then calculated by averaging the three obtained water volumes. Average Volume = (9.48 mL + 9.92 mL + 9.96 mL) 3 = 9.91 mL
Discussion:
Instruments that are both precise and accurate provide the best …show more content…
The average water volume calculated for the burette was 10.029 mL, which is 0.029 mL from the actual water volume of 10mL. Because, 0.029 mL was the smallest difference from the actual 10 mL, it is considered the most accurate piece of equipment. On the contrary, the least accurate instrument, the graduated cylinder, provided an average water volume of 9.672 mL, which is 0.328 mL from 10 mL, the largest difference presented from the three instrument