Buffer solutions and pH curves Flashcards Preview

Topic 12.2 (Acid-base titrations) > Buffer solutions and pH curves > Flashcards

Flashcards in Buffer solutions and pH curves Deck (4)
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1

the buffer range on pH curve is the............region

the flatter region on the left side of the equivalence point

2

in the buffer range of a pH curve, the pH change is.............and over this range the concentrations of both acid and conjugate base molecules is................

gradual change
considerable concentrations of both

3

the experimental method for calculating Ka from a pH curve is:

-titrating a strong base with a weak acid
-plot a graph of pH against the volume of base added
-from the graph, the minimum volume of base required to to completely react with all the acid is determined at the equivalence point
-the pH at the half equivalence point is then calculated as this value is equal to the pKa value of the weak acid
-as Ka = 10 (-pKa) (to the power of)

4

the equation linking Ka and pKa is:

Ka = 10(-pKa)
pKa = -lg Ka