Acid Base Equilibria
In part one, solution was slowly titrated until an obvious change in pH occurred.
On a pH
titration graph at the point of equivalence point there is a great increase in pH.
Using this
fact and a pH meter the equivalence point was determined.
The Ka value was a little high
because the exact value of equivalence was passed during the titration.
The formula for
this part is CH
3
OOH
H+CH
3
COO.
In Part one the calculated Ka’s for the solutions are very close to the actual Ka.
2.5x10^5,
1.9x10^5, and 2.6x10^5 are all very close to the actual Ka of 1.76x10^5.
The Calculated
Ka’s are higher because of measuring and rounding error in the experiment.
The
graduated cylinder only measures to .1ml and the pH meter only reads to one decimal place.
Adding that to rounding error can explain why the Ka is larger than its actual value.
In the
first measured pH versus actual pH there was 0% difference indicating that the two pH’s
are equal, and in the second there was only a 5% difference.
This indicates that the
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 Spring '07
 Hooker
 Valence, pH, Test method, pH meter

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