Here's How to .....make a solution of a particular molarity.
CONCEPT: Molarity defines the
concentration of a solution. To make molarity measurable one needs to
convert formula weight of the chemical substance into grams. The weight of this
unit is known as a mole (Avogadro's Number). Unlike the mole pictured to
the left, in a chemical mole there are 6.02 x 10 23
gloves and goggles and label all solutions!
||To make a 1Molar
solution of a compound...
Determine the mass required for
liter of the solution as follows:
- To determine the mass, find the formula weight for the
compound. Ex. for NaCl the FW is 58, combine the atomic mass of
Na (23) and Chlorine(35) = 58 grams
|Balances need to
be zeroed - with the empty weighing pan on the balance, push the
out the required mass (in the example above 58 grams of NaCl is necessary for an 1 molar solution).
Place desired mass into a
beaker or flask.
||Add about 80%
of the total amount of distilled water to the beaker, stir and
heat until dissolved.
To finish, add enough distilled water to the beaker to reach the
final volume needed.
Reduce mass proportionally to the amount of volume needed.
Example: If you need 100ml of solution, mass would be 5.8 grams of NaCl
50 ml solution, mass = 2.9 grams of NaCl