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备课人:丁海林. New word Solubility Solubility curve Solute Sugar (sucrose) solvent Salt (sodium chloride) solution crystallisation Insoluble Supersaturation.

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Presentation on theme: "备课人:丁海林. New word Solubility Solubility curve Solute Sugar (sucrose) solvent Salt (sodium chloride) solution crystallisation Insoluble Supersaturation."— Presentation transcript:

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


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