Other slides in this set
This part of C3 appears to be difficult.
It isn't, it's actually VERY straightforward.
However, you will need to concentrate,
and attempt all the exercises.
Make sure your notes are clear.
You WILL need a calculator
Introduction & a definition
Titrations are used to work out the
concentration of an unknown solution.
You can also work out how much of a
solution will be needed for neutralisation
of a known concentration.
Concentration: the number of moles of
a solute in 1dm3 solution.
(1 dm3 = 1000cm3)
Example 1 (follow carefully...)
Calculating concentration of a solution from a known
mass of solute.
If 40g NaOH is used to make 500cm3 of solution,
what is the concentration in mol/dm3?
40 x1000 = 80g of NaOH in 1000cm3
1 mole of NaOH = 40g (RAM in g)
So, 80g = 2 moles
So, the concentration of the NaOH solution is 2
Example 2 (still following?)
Calculating the mass of a substance in a known
What is the mass of H2SO4 in 25ocm3 of 1mol/dm3?
1 mole H2SO4 = (1x2) + 32 + (16x4) = 98g
1mol/dm3 concentration = 98g H2SO4 in 1000cm3 of
98x 250 = 24.5g H2SO4 in 250cm3 of 1mol/dm3
In a titration, we have 2 solutions
One (in burette) is a known concentration
The other (in the conical flask, measured to a
known volume using the pipette & filler) is a
known substance, but unknown
The result of the titration can help us
calculate the number of moles of a
substance in the solution in the conical