Specification points:
· the techniques and procedures used in experiments to measure volumes of solutions; the techniques and procedures used in experiments to prepare a standard solution from a solid or more concentrated solution and in acid-base titrations.
Key definitions:
- Acid = H+ donator
- Base = H+ acceptor
- Concentrated = contains more solute than solvent
- Dilute = contains more solvent than solute
For example:
You are asked to make 250 cm³ of a standard solution of potassium carbonate. You will need to weigh out 2.5 g of solid.
Write a method to make this solution.
Include all the equipment needed.
Mention any steps you would take to ensure that the solution has the correct concentration.
You will need:
250 cm³ Conical flask
Beaker
2.5g of solid (Potassium carbonate)
Distilled water
Balance
Funnel
Glass rod
Dropping Pipette
Method:
1. Weight out 2.5g of Potassium carbonate using a balance.
2. Dissolve the solid in 100cm³ of distilled water in a beaker
3. Stir with a glass rod until all the solid has dissolved.
4. When completely dissolved, use a funnel to transfer the solution to a 250cm³ volumetric flask
5. Wash out the beaker several times with distilled water and add the washings to the flask.
6. Add distilled water close to the mark, then use a dropping pipette to add the last drops of water so the bottom of the meniscus is on the line.
7. Place the lid on then invert the flask to mix.
8. Your standard solution is now ready.
Comments