Performing the Titration

Question 1

he key piece of equipment used in the titration is the burette

Burettes are usually marked to a precision of 0.10 cm3

Since they are analogue instruments, the uncertainty is recorded

Answer 1

to half the smallest marking, in other words to ±0.05 cm3

Question 2

The end point or equivalence point occurs when the two solutions have reacted

Answer 2

completely and is shown with the use of an indicator

Question 3

A white tile is placed under the conical flask while the titration is performed,

Answer 3

to make it easier to see the colour change

Question 4

Measuring a known volume (usually 20 or 25 cm3) of one of the solutions with a ……… and placing into

Answer 4

a volumetric pipette and placing it into a conical flask

Question 5

The other solution is placed in the burette
To start with, the burette will usually be filled to

Answer 5

0.00cm cubed

Question 6

A few drops of the………………. are added to the solution in the …………..

Answer 6

indicator

conical flask

Question 7

The tap on the burette is carefully opened and the solution added, portion by portion, to the conical flask until the indicator

Answer 7

starts to change colour

Question 8

As you start getting near to the end point, the flow of the burette should be

Answer 8

slowed right down so that the solution is added dropwise
You should be able to close the tap on the burette after one drop has caused the colour change

Multiple runs are carried out until concordant results are obtained
Concordant results are within 0.1 cm3 of each other

Question 9

percentage uncertainty equation

Answer 9

percentage uncertainty = uncertainty / measured value x 100

Question 10

Using a burette to find the initial reading and final reading
In all these example you have to read the instrument twice to obtain the quantity
If each you time you read the instrument the measurement is ‘out’ by the stated uncertainty, then your final quantity is potentially ‘out’ by twice the uncertainty