14.2Concentrationofsolutionssssssss).pptx

14.2Concentrationofsolutionssssssss).pptx

1. Concentration of solutions Chapter 14 – section 2

2. Objectives: Define molarity, and calculate the molarity of a solution. Define molality, and calculate the molality of a solution . Describe the procedure for preparing a solution of a certain molarity .

3. What is concentration? Is a measure of the amount of solute in a given amount of solvent or solution

4. What is Molarity? Is the number of moles of solute in one liter of solution The unit is molar (M)

5. Sample problem: What is the molarity of a potassium chloride solution that has a volume of 400.0 mL and contains 85.0 g KCl ?

6. What is Molality? Is the concentration of a solution expressed in moles of solute per kilogram of solvent The unit is molar (m)

7. Sample problem: What is the molality of a sodium chloride solution that has a 400 g and contains 55g NaCl ?

8. Preparing solution of a specified molarity: Prepare 1 liter of 0.5 M of CuSO 4 Page 463

9. How do you Prepare 1 liter of 0.5 M of CuSO4? Find out the mass of the substance Add the amount of mass to a volumetric flask. Fill the flask up to 1 liter. Shake it well Molarity = moles / Volume (L)  0.5 = n / 1 = 0.5 mol Number of moles = mass / M.M  0.5 = mass / 249.68 = 124.8 g