RP9 - Investigating pH changes Flashcards
What is an acid?
A proton donor.
What is a base?
A proton acceptor.
What is an alkali?
A base that dissolves in water.
Why are acid-base indicators used?
To detect when a reaction reaches
completion/becomes neutral, usually by the presence of a colour change.
Why does a pH probe need to be calibrated?
So that the pH values for each pH reading are accurate.
What is accuracy?
The more accurate the data, the closer it
is to the actual value.
How can you investigate how a weak acid’s pH changes upon addition of strong base?
Add 2 cm3 of NaOH from a burette to
ethanoic acid, in a conical flask.
Continue adding 2cm3 of NaOH,
measuring the pH each time.
Why is it important to stir the resulting solution?
So all acid and base is thoroughly mixed, so the pH doesn’t significantly vary
throughout the solution as this would
give an inaccurate reading.
How would you analyse this data?
Plot a graph of measured pH values
(y-axis) against volume of NaOH
solution added (x-axis).
What is the shape of the curve
