A student put 25.0 cm3 of Na(OH) solution with an unknown concentration into a conical flask using a pipette. The sodium hydroxide reacted with exactly 20.0 cm3 of 0.50 mol/dm3 HCl added from a burette. What was the concentration of the sodium hydroxide?

1)Moles of HCl added0.50 x (20.0/1000) =0.010 moles of HCl2) Moles of Na(OH)0.010 moles3) Concentration of Na(OH)25 cm3 = 0.025 dm3

0.010/0.025 = 0.40 moles/dm3

Solubility curves

L.O.: Explain how solubility changes with temperature and pressure.

Predict what will happen when we cool a saturated solution.

• What is there in our water?

Water contains calcium and magnesium salts.

• What type of compounds dissolved in water?

Ionic compounds dissolved in water.

What about gases?

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

The solubility of most solid solutes increases as the temperature rises

• Saturated solution

A solution in which no more solute will dissolve

• Task:1)Workbook pages 117-1182)Extension: workbook 115-116