1. A student put 25.0 cm 3 of Na(OH) solution with an unknown concentration into a conical flask using a pipette. The sodium hydroxide reacted with exactly 20.0 cm 3 of 0.50 mol/dm 3 HCl added from a burette. What was the concentration of the sodium hydroxide? 1)Moles of HCl added 0.50 x (20.0/1000) =0.010 moles of HCl 2) Moles of Na(OH) 0.010 moles 3) Concentration of Na(OH) 25 cm 3 = 0.025 dm 3 0.010/0.025 = 0.40 moles/dm 3

2. Solubility curves L.O.:  Explain how solubility changes with temperature and pressure.  Predict what will happen when we cool a saturated solution.

3. What is there in our water? Water contains calcium and magnesium salts.

4. What type of compounds dissolved in water? Ionic compounds dissolved in water. What about gases?

5. Solubility: amount of solute in grams that can be dissolved in 100 grams of solvent.

6. The solubility of most solid solutes increases as the temperature rises

8. Saturated solution A solution in which no more solute will dissolve

9. Task: 1)Workbook pages 117-118 2)Extension: workbook 115-116