mass
'no magic to the mole'
amount
molar mass
concentration
solution volume
gas volume
molar gas volume
Avogadro
constant, L
number of
entities, N
Now try the following question.
F6. CALCULATIONS INVOLVING CONCENTRATION, AMOUNT & VOLUME - 1
To begin with, two facile – easy – worked examples are considered.
These problems would more likely be set with the volume expressed initially in units of cubic centimetre, cm , or millilitre, mℓ or mL. These are the units that are normally most convenient for the majority of laboratory volume measurements with standard titrimetric glassware like volumetric flasks, pipettes, burettes, etc.
3
We shall now attempt the second example for LiOH again, but starting with a volume given in cm .
3
Although the last of these approaches is undeniably attractive, it is of the least use with ‘A’ level / IB / pre-U
concentration units according to Examiner mark schemes.
ASIDE: MONITORING BLOOD GLUCOSE LEVELS
However, the use of mmol (millimole) can be a convenient alternative, particularly when dealing
with biological fluids whose concentrations tend to be very dilute:
One way of measuring blood glucose levels – aka blood sugar level – is in terms of an amount concentration which, in practice, takes units of
which are all equivalent and refer to the concentration of glucose in the blood.