Chemistry - Errors and correct technique in volumetric analysis
Errors and correct technique in volumetric analysis
As with all practical procedures there are errors associated with
Systematic errors such as those associated with manufacturer's accuracy of
balances and glassware are unavoidable but the effect of these errors can
be significantly reduced by properly designed experiments.
Random errors such as missing the endpoint of a reaction or spilling some
of a reaction mixture may be reduced by repeating the analysis.
Consider the impact of the errors associated with using of a burette
during a titration.
The use of a burette during titration requires three 'measurements':
* initial reading of the scale,
* recognition of the endpoint and
* final reading of the scale.
The cumulative uncertainity (error) in a measured volume from a burette
may be as high as plus or minus 0.12 mL.
In a titre of 2.00 mL this accounts for an error of (0.12 / 2.00) x 100 =
In a titre of 20.0 mL however, the error is [0.12 / 20.0] x 100 = 0.6%.
This again emphasises why a titre of 20 mL is preferrable to a titre of 2
mL and the importance of including this consideration in experimental
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