Essay on Determination of the identity of an unknown liquid

1637 Words Oct 2nd, 2013 7 Pages
Chemistry Lab
Report

Purpose
The purpose of this lab is to determine the identity of an unknown liquid by measuring its density and its boiling point and try to match it with those solutions given in Table 2 of experiment 2.

Procedure
Part A
In Part A, The main purpose was to find the determination of the density of the unknown (j41) and by doing that we had to determine volumes of the unknown liquid (j41) using three different volumetric devices which are graduated cylinder, pipette and burette. Then we had to perform three measurement trials on each device.
Graduated cylinder: I dried a clean 50.0 ml graduated cylinder and also measured with a balance and I got 66.39g after measuring the empty cylinder I added
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I don’t think there was any data that was useless in this experiment because each made a participation in finding the density or boiling point of the unknown solution.

2)

When measuring the density of the unknown liquid I used the graduated cylinder, volumetric pipette and burette. The graduated cylinder was accurate to +-0.5 while the volumetric pipette was accurate to +-0.01 and when measuring with the pipette I noticed that I measured 10ml with the pipette but when
I poured the liquid into a beaker it was measuring up to 40ml that was when I concluded that the pipette was very accurate and very much more accurate than the beaker. The burette was accurate to +- 0.04, the burette is so accurate but not as accurate as the pipette. The pipette is like a calculator with the full value of the measurement given while the burette is also like a calculator but with estimating values and the graduating cylinder is like a human trying to get the measurement of liquid with just his/her brain. If I was to repeat this experiment I would use the volumetric pipette since it is the most accurate out of the three.
3) The nature of the devices obviously limited the precision of my measurements and there was a significant error when measuring the density of the unknown liquid using the pipette I accidently used a 25ml pipette instead of 10ml which would have made my average value for my density get higher because when I

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