Laboratory work
Making a standard solution
Purpose of the work:
In this activity you will be introduced to the concentration
measurment of molarity, and you will learn how to do the necessary calculations
to prepare molar solutions, or solutions of a specific molarity.
Materials:
·
Solid
·
Distilled water
·
250 mL beaker
·
Beaker Stock
·
Balance
·
massing paper
·
scoopula
Procedure:
1.
Accurately weight a substance for dissolving using a watch glass or a
beaker (both must be clean and dry).
2.
Carefully pour the solid into a volumetric flask. You may use a lab
funnel to avoid spilling the substance.
3.
Half fill the flask with water and accurately stir it. Do not turn
over the flask.
4.
Fill the flask with water until it is up to the ring graduation
marking. The bottom of the water meniscus should be on the same level as the
ring.
5.
Close the flask with a stopper and turn over the flask several times
to complete mixing.
Questions:
1.
40 g of sugar dissolved in 250 ml of water. Calculate the mass
fraction of sugar in this solution.
2.
Calculate the mass of soluble and solvent in 500 grams of 15% NaOH
solution.
3.
How many grams of hydrogen per 100 ml of solution of 36% HCl (ρ =
1,183 g / mL)? Calculate molar, equivalence concentrations and titres of this
solution.
4.
How many grams a solution of 0.5 L 96% H2SO4 (ρ
= 1,84 g / ml)?
5.
26% KOH solids density is 1.24 g / ml. How many KOH concentrations
are there in 5 liters of this solution?
6.
How many grams of potassium sulphate dissolved in 200 ml of solution
of 1N K2SO4.