1. Concentration Chin-Chin Salonga 11A

2.  The majority of reactions are carried out in solution rather than in the gaseous phase.  Solution – a homogenous mixture of a solute that is being dissolved in the solvent  Solvent – what dissolves the solute /solution  Aqueous solution – the solvent is water

3. Molar concentration

4. Units of concentration  Mass per unit volume, g dm -3  Mol per unit volume, mol dm -3  Parts per million (ppm): one part in 1 x 10 6 parts. 1 ppm = 1 mg dm -3

5. Concentration calculations  Example 1: Molarity of solution Calculate the concentration, in mol dm -3, of a solution formed when 0.475g of magnesium chloride, MgCl 2 is completely dissolved in water to make a solution with a volume of 100 cm 3.

6. Example 1: solution

8. Example 2: Concentration of ions Determine the concentration, in mol dm -3 of the chloride ions in example 1 above.

9. Example 2: solution

10. Example 3: Mass of solute Calculate the mass, in g, of potassium hydrogen phthalate, C 8 H 5 O 4 K (a primary standard) om 250 dm 3 of a 1.25 mol dm -3 solution.

11. Example 3: solution

12. Example 4: Concentration of standard solution A standard solution is prepared by dissolving 5.30g of sodium carbonate, Na 2 CO 3 in 250 cm 3 of distilled water in a volumetric flask. A 10.0 cm 3 sample of this solution is removed by bulb pipette and diluted with water to a final volume of 0.100 dm 3. Calculate the concentration, in mol dm -3, of the diluted solution.

13. Example 4: solution

15. Practice problems 1. A solution of calcium sulphate, CaSO 4, contained 0.500g dissolved in 2.00 dm 3 of water. Calculate the concentration in a) g/dm 3 and b) g/cm 3.

16. Practice Problem 1: solution

17. Practice Problem #2 Calculate the concentration, in mol dm -3, of a solution formed when 1.745g of calcium chloride, CaCl 2, is completely dissolved in water to make a solution with the volume of 100 cm 3.

18. Practice problem 2: solution