1. 备课人：丁海林

2. New word Solubility Solubility curve Solute Sugar (sucrose) solvent Salt (sodium chloride) solution crystallisation Insoluble Supersaturation saturated solution unsaturated solution Limestone (calcium carbonate)

3. What is solubility? The solubility of a substance refers to the maximum amount of that substance that can be dissolved in a given quantity of solvent at a certain temperature.

4. Measuring solubility ① at a particular temperature ② 100 grams ofsolvent （一 般为水） ③ maximum mass of solute ( 达到饱和）④溶质的 质量（单位为克） To determine the maximum mass of solute that can be dissolved in 100 grams of solvent at a particular temperature 1 、 One way of measuring solubility ： 注意点 : (1) 理解这个概念，抓住四个要素 :

5. Solubility curve The relationship between solubility and temperature can be represented by a solubility curve

6. key questions 2.What is the solubility of the following solids at 20°C? a sodium nitrate b potassium nitrate c sodium chloride 1.Use the solubility curves in Figure 11.1 to answer the following questions. 1 At what temperature is the solubility of potassium nitrate: a 50 g/100 g? b 100 g/100 g? c 150 g/100 g? a 30°C b 55°C c 62°C a 82 g/100 g b 36 g/100 g c 36 g/100 g

7. 4.What mass of the following compounds will dissolve in 200 g of water at 30°C? a CuSO 4.5H 2 O b KNO 3 c NaNO 3 3.What mass of the following compounds will dissolve in 100 g of water at 40°C? a CuSO 4.5H 2 O b KNO 3 c NaNO 3 a 25 g b 65 g c 100 g a 42 g b 96 g c 184 g

8. An 80 g sample of NaNO 3 is added to 200 g of H 2 O at 20°C. Use the solubility curve in Figure11.1 to calculate how much more NaNO 3 needs to be added to make the solution saturated with NaNO 3 at 20°C. Worked example 11.1b Solution From the solubility curve, at 20°C a saturated solution of NaNO 3 contains 85 g of NaNO 3 in 100 g of H 2 O. So, in 200 g of water, mass of NaNO 3 needed to make a saturated solution:= 2 × 95 g = 190 g 80 g of NaNO 3 has already been added to 200 g H 2 O. So the extra amount of NaNO 3 needed: = 190 − 80 g= 110 g

9. Crystallisation The sugar that will no longer stay dissolved comes out of solution as crystals. This process is known as crystallisation

10. Worked example 11.1c What happens if a solution containing 50 g of potassium nitrate in 100 g of water is allowed to cool from 40°C to 20°C? Solution The solubility curve of potassium nitrate (Figure 11.1) shows that, until the solution drops to 32°C, the 50 g of solute will remain in solution. At 32°C, 50 g of potassium nitrate is just enough to saturate 100 g of water. As soon as the temperature drops a little more, there is more solute present than can remain dissolved, so crystallisation begins. At 20°C, the solubility of potassium nitrate is 32 g per 100 g.So amount solid that will crystallise out of solution:= 50 − 32 g= 18 g

11. 1.What mass of copper sulfate needs to be dissolved in 50 g of water to make a saturated solution at 40°C? 14 g 2. 25 g of potassium nitrate is dissolved in 100 g of water at 30°C. Is this solutionsaturated? No 3.If 100 g of KNO 3 is added to 100 g of H 2 O at 40°C, how much of it will remaim undissolved? 35 g