Calibration of Pipettes and Burettes
Lab 1: Calibration of Pipettes and Burettes
Names
TA Name, Thursday Lab: 1:40 P.M. - 4:10 P.M.
Aim:
This experiment sought to gather data regarding water volume gathered in glassware, then to statistically analyze the data, focusing on average and standard deviation, along with relative error gleaned from linear regression.
Introduction:
This experiment was divided into two parts. For part one of the experiment, 25 mL were transferred from a glass pipette to a tarred beaker and weighed using an analytical balance.
Temperature was noted at 21.5 degrees Celsius. Procedure was performed 20 times for a pipetter and 20 times for a glass pipette, with one student performing the entire experiment once, and another student performing the entire experiment a second time (Instructions, 2013).
Density, average volume of water delivered, standard deviation, and percent relative deviation were calculated, with accuracy, precision, and outliers considered. Since standard deviation was less than 10%, data was deemed acceptable and further subject for comparison of actual value to nominal value, and a t-test was used to find confidence interval (Skoog, 2004).
For the second part of the experiment, a glass burette was marked and filled to 0 mL.
Water was delivered to 1 mL and mass was determined. Water was then delivered to 5 mL, 10 mL, 20 mL, 35 mL, and 50 mL in turn. All of this was repeated a total of 2 times. Volume of water was determined, then average and standard deviation calculated for each volume. Finally, linear regression was used to find line of best fit and determine whether calculations were within tolerance (+/- 0.05 mL).
Results:
Pertinent equations: ρ = m/V where ρ = density (g/mL) m = mass (g)
V = volume (mL) xbar = (x1+x2+...+xN)/N where xbar = average x1, x2, …, xN = sample values
N = number of samples
δ = √(1/N) * (x1-μ)2+(x2-μ)2+…+(xN-μ)2
where δ = standard deviation
N = number of samples x1, x2, …, xN =
Names
TA Name, Thursday Lab: 1:40 P.M. - 4:10 P.M.
Aim:
This experiment sought to gather data regarding water volume gathered in glassware, then to statistically analyze the data, focusing on average and standard deviation, along with relative error gleaned from linear regression.
Introduction:
This experiment was divided into two parts. For part one of the experiment, 25 mL were transferred from a glass pipette to a tarred beaker and weighed using an analytical balance.
Temperature was noted at 21.5 degrees Celsius. Procedure was performed 20 times for a pipetter and 20 times for a glass pipette, with one student performing the entire experiment once, and another student performing the entire experiment a second time (Instructions, 2013).
Density, average volume of water delivered, standard deviation, and percent relative deviation were calculated, with accuracy, precision, and outliers considered. Since standard deviation was less than 10%, data was deemed acceptable and further subject for comparison of actual value to nominal value, and a t-test was used to find confidence interval (Skoog, 2004).
For the second part of the experiment, a glass burette was marked and filled to 0 mL.
Water was delivered to 1 mL and mass was determined. Water was then delivered to 5 mL, 10 mL, 20 mL, 35 mL, and 50 mL in turn. All of this was repeated a total of 2 times. Volume of water was determined, then average and standard deviation calculated for each volume. Finally, linear regression was used to find line of best fit and determine whether calculations were within tolerance (+/- 0.05 mL).
Results:
Pertinent equations: ρ = m/V where ρ = density (g/mL) m = mass (g)
V = volume (mL) xbar = (x1+x2+...+xN)/N where xbar = average x1, x2, …, xN = sample values
N = number of samples
δ = √(1/N) * (x1-μ)2+(x2-μ)2+…+(xN-μ)2
where δ = standard deviation
N = number of samples x1, x2, …, xN =