Accuracy and Precision
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Experiment #4
Weighing and Volumetric Techniques — Accuracy and Precision
Abstract
The purpose of this experiment is to become familiar with proper techniques for using the analytic balances, graduated cylinder, burette and pipette and determine which is more accurate and/or precise. In this experiment, the burette and pipette were more exact than the graduated cylinder and the analytic balance gave a very accurate and precise answer.
Results / Report
1) Weighing Copper
Copper sample #: 1
Balance #: 14
Temperature: 22.8EC
Weighing Attempt #
Mass of Copper Sample (g)
3.1234
3.1233
3.1235
3.1232
Average Mass
= (3.1234g + 3.1233g + 3.1235g + 3.1232g) Д* 4
=3.1234g
Standard Deviation
( – )
( – )
3.1234
3.1233
3.1235
3.1232
ОЈ =
Or 0.0001
2) Burette Readings
a) Graduated Cylinder
b) Pipette
Initial Volume (mL)
44.72
44.91
Actual amount added (mL)
Actual amount added (mL)
34.81
34.98
24.90
25.00
15.05
15.08
Graduated Cylinder average
( 9.91б0.01 mL + 9.91б0.01 mL + 9.85б0.01 mL ) Д* 3
= 9.89б0.03 mL
Pipette average
(9.93б0.01 mL + 9.98б0.01 mL + 9.92б0.01 mL) Д* 3
= 9.94б0.03 mL
Device
Initial Mass (g)
Final Mass (g)
Resulting Water Mass (g)
Graduated Cylinder
21.5291
31.2987
9.7696
Pipette
20.5674
30.4927
9.9253
Burette
21.2779
31.3261
10.0482
TRUE VALUES
Graduated Cylinder
Density @ 24.3EC = 0.997225g/mL
Volume = Mass Д* Density
= 9.7696g Д* 0.997225g/mL