The Precision Of A 50 Ml Beaker

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The precision of a 50 ml beaker, 25 ml grad. cylinder., and a 25 ml pipette were determined by transferring each type to a tared 50 ml beaker. The density of copper was determined through volume displacement in water. The pipette was fond to be the most precise with a mean volume of 24.843±0.184ml. While the 25 ml cylinder had a volume of 24.601±0.708 ml and the 50 ml beaker had a volume of 24.074±1.98 ml. The density of copper was found to be 9.190±0.836, with an accuracy of 2.567%. The difference in density measurements could be due to human error or temperature differences.
Background: Previously submitted on D2l.
Procedure: Hirko, R. Chemistry 112L General Chemistry I Laboratory, Ninth Edition; bluedoor: Minneapolis, 2015; Experiment 1.
Results:

Vessel T/°C H2) Mass/g Density/ g/cc V/ mL
50 mL beaker 21.1° 23.454 0.99797 23.502
50 mL beaker 21.1° 24.935 0.99796 24.986
50 mL beaker 21.1° 23.687 0.99797 23.735
Mean Volume 24.074
Uncertainty 1.98
25 mL grad. Cyl. 20.7° 24.806 0.99799 24.292
25 mL grad. Cyl. 20.9° 24.268 0.99804 24.854
25 mL grad. Cyl. 20.8° 24.609 0.99802 24.657
Mean Volume 24.601
Uncertainty 0.708
25 mL pipette 21.4° 24.837 0.99791 24.889
25 mL pipette 21.3° 24.829 0.99789 24.881
25 mL pipette 21.3° 24.706 0.99792 24.757
Mean Volume 24.843
Uncertainty 0.184

Trial 1 Trial 2 Trial 3
Mass dry cylinder /g 27.250 27.337 27.260
Mass dry cylinder + metal / g 61.331 61.415 61.335
Mass dry cylinder + metal + water to 10.00 ml mark 67.961 67.487 67.410
Mass metal / g 34.081 34.078 34.075
Mass water/ g 6.63 6.072 7.075
Volume water/ cc 6.644 6.085 6.088
Volume metal / cc 3.356 3.915 3.912
Density metal / g/cc 10.155 8.704 8.71
Mean Density ± Uncert...

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... error that may be present is inconsistent temperatures. In each of these trials temperature was never measured to make sure the number was actually 21°C. This temperature discrepancy could lead to inaccuracies in finding the mean density.
To improve part 2 of this experiment more accurate measurements are needed. More time needs to be spent on obtaining an accurate measurement of water up to the 10 ml line. Temperature also needs to be taken before each trial to accurately calculate the mean density for each trial. Adding a trial with a liquid, other than water, would require changes in the numbers used to calculate the density of the metal, but could provide additional data to confirm the density found.

Acknowledgements:
I would like to recognize my lab partner Chad White for assistance in the experiment, my TA Amos Dwamena, and my lab coordinator Mandy Orth.

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