The student should
follow following steps to make 1 L of 2.0 M CaCl₂.
1. First he should
calculate the number of moles of 2.0 M CaCl₂ in 1 L solution.
Molarity of the solution = 2.0 M
Volume of solution which should be prepared = 1 L
Molarity =
number of moles / volume of the solution
Hence, number of moles in 1 L = 2 mol
2. Find
out the mass of dry CaCl₂ in 2 moles.
moles =
mass / molar mass
Moles of CaCl₂ =
2 mol
Molar mass of CaCl₂ = 110.98 g/mol
Hence, mass of CaCl₂ = 2 mol x 110.98 g/mol
= 221.96
g
3. Weigh the mass
accurately
4. Then take a cleaned and dry1 L volumetric flask and place a funnel top of it. Then carefully add the salt into the volumetric flask and
finally wash the funnel and watch glass
with de-ionized water. That water also should be added into the volumetric
flask.
5. Then add some
de-ionized water into
the volumetric flask and swirl well until all salt are
dissolved.
6. Then top up to
mark of the volumetric flask carefully.
7. As the final step prepared solution should be labelled.
