1. Starter for 10 Connect your learning Sit back to back – label yourselves A & B

2. Starter for 10 Connect your learning Solvent

3. Starter for 10 Connect your learning Solution

4. Starter for 10 Connect your learning Solute

5. Starter for 10 Connect your learning Concentration

6. Match up the following words and definitions. Solvent Solute Solution Formed when a substance dissolves in a liquid. The liquid part of the solution that the substance dissolves in. The substance that dissolves in the liquid. Concentration How much solute is dissolved in the solvent

7. Learning outcomes (c) State how to make a standard soluton (B) Calculate the amount of substance in mol, using solution volume and concentration (A/A*) Calculate the mass of a solute needed to prepare a certain volume of a standard solution

8. What units are used to measure concentration? g cm 3 mol dm -3 cm 3 mol dm 3

9. If the volume of the solution is measured in dm 3. n = c x V Where n = amount of substance, in mol c = concentration of substance, in mol dm -3 V = volume of solution, in dm 3 NB if the volumes are small (i.e. cm 3 ) divide V by 1000 Complete question 1 from the text book

10. Standard solutions Solution of known concentrations Used in titrations You will firstly calculate an example and then use your results to make up a standard solution Use a volumetric flask – two types available, find out what they are and when you should use each type

11. To calculate a standard solution you need to; 1.Consider the volume of solution required 2.Work out the amount, in mol, of solute needed 3.Convert the amount of solute to a mass, in g, so you know how much to weigh out

12. Examples In a solution with a concentration of 4 mol dm -3 there are 4 moles of solute dissolved in every 1 dm 3 of the solution. In 1 dm 3 there are 4 mol of dissolved solute In 2 dm 3 there are 8 mol of dissolved solute In 0.25 dm 3 there is 1 mol of dissolved solute If you know the concentration in mol dm -3, you can find the amount, in mol, in any volume of solution

13. Worked example Find the mass of KOH required to prepare 250 cm 3 of a 0.200 mol dm -3 solution

14. Worked example Find the mass of KOH required to prepare 250 cm 3 of a 0.200 mol dm -3 solution 1.Find the amount of KOH, in mol, required in the solution: n (KOH) = c x V/1000 = 0.200 x 250/1000 = 0.0500 mol 2. Convert moles into grams Molar mass, M(KOH) = 39.1 + 16.0+ 1.0 = 56.1 g mol -1 Amount n = mass m molar mass M Hence, m = n x M = 0.0500 x 56.1 = 2.805g

15. Calculate Find the mass of sodium chloride required to prepare 250cm 3 of a 0.300 mol dm -3 solution When calculated we are going to make up a standard solution based on the results

16. Molar solutions Referred to as ‘M’ on bottles e.g. 2M HCl M means molar and refers to a solution with a concentration in moles per dm -3 2 mol dm -3 and 2M means the same thing! Question 3 from the text book

17. Complete questions 1-3 on pages 17 in the text book Last weeks homework (exam questions, on the wiki lesson 6) – complete questions 1iii and 2ii Homework