Introduction
An ordinary laboratory pipette may be expected to deliver its nominal volume with good precision and good accuracy if it is used in the way recommended. In this experiment we investigate the precision and accuracy of such a pipette by making accurate determinations of the mass of water it delivers in repeated operations.

Materials
10.0-cm3 pipette, 50-cm3 beaker, thermometer, pipette filler, graph paper.
Procedure (Read carefully)
1.Clean the beaker and the pipette and dry the beaker.

2.Obtained distilled water in an Erlenmeyer flask and let it stand on the bench for about 15 min before determining its temperature.
3.Weigh the beaker on a balance which allows you to determine the mass to the nearest tenth of a milligram (i.e. ± 0.001 g).
4.Fill (use the pipette filler) and discharge the pipette as recommended, into the beaker, and determine the mass of water discharged by taking the difference.
5.Repeat step 4 until you have the results of four (4) such trials.

Note: You do not need to empty and dry the beaker between trials. Also, you should try not to spend more than a half-hour in the balance room doing this, so that everyone can have a chance to use the balances in the time allotted.

7.Determine the temperature of the water you have pipetted and take the mean of the two temperatures you have measured as the effective temperature of the water during the calibration.
Calculations
1. Find the mean of the four trials. The mean volume can now be determined from the mean mass and the density of water at the temperature you determined in 6 above. However, there is a correction to be made for the upthrust of air on the water during the weighing. In normal day-to-day use of balances we neglect this correction, but now that we are interested in accurate calibration, we will take this into account. The correction occurs because the upthrust of air on...

...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...

...Determining the accuracy of varieties of pipettes by weighing and finding the density of a liquid
Abstract
Different varieties of pipettes (P100, PR1000 pipettors and a serological pipette) along with a weighing balance was used in this investigation to check the density of an unknown liquid by first finding out what the liquid weighed and plotting a graph of the mass in grams against the volume of the liquid used in micro litres (µl) and finding...

...REACTION PAPER
THE WOUNDED PLATOON
Kevin Shields, a 24-year old Army Soldier, went out drinking with three Army buddies on November 30, 2007, from Fort Carson, Colorado, a base close to Colorado Springs. A few hours later, he was dead. He was shot twice in the head at close range and left by the side of the road by his army buddies. Shields' violent murder accentuated one of many violent attacks committed by the three Army buddies, who are now serving...

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