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Solubility Do Now: p.4. Remember…likes dissolve like. Things that dissolve in water Soluble ionic Acids (ex HCl ) Bases (ex. NaOH ) Polar covalent molecules. When Ionic Compound dissolved in water they dissociate= hydration. Cl -. CH 4 NaCl H 2 O CCl 4 CH 3 OH H 2 S CaBr 2
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Remember…likes dissolve like • Things that dissolve in water • Soluble ionic • Acids (ex HCl) • Bases (ex. NaOH) • Polar covalent molecules
When Ionic Compound dissolved in water they dissociate= hydration Cl-
CH4 NaCl H2O CCl4 CH3OH H2S CaBr2 C6H14 NH3 NH4OH C4H10 PH3 CH3CH2OH Identify the nature of each of the following as PC, NPC, or ionic. Ionic Nonpolar Cov. Nonpolar Cov. Ionic Polar Cov. Polar Covalent Polar Cov. Nonpolar Cov. Polar Cov. Polar Cov. Ionic Now try p.8 Nonpolar Cov. Polar Cov.
Solubility = the max amount of solute that can be dissolved in a solvent • Many solidsand gases dissolve in water • As you increase the temperature, you can dissolve more solid • Does this work the same with gas? • NOT the same for gases – as you increase temp, gas molecules KE • Where can you go to find if an ionic compound is soluble or insoluble in water? • Table F
Summary: Factors Affecting Solubility • Nature of the solvent and the solute: LIKE DISSOLVES LIKE • Temperature • Pressure (for systems with gases)
Factors that affect the rate at which something dissolves • Temperature • Stirring or agitation • Surface area (crushing/grinding)
Solubility curves show the relationship between solubility and temperature. • Can you guess which of these compounds are gases?! How do you know?!
Reading a solubility curve?! Table G tells you the max amount of solute you can dissolve in 100 g of H2O at a given temperature
Problem: How much KCl will dissolve in 100g of water at 50C? X = 42g KCl
Problem: How much KCl will dissolve in 300g of water at 50C? Hint: Use the graph to set up a proportion 42 g KCl = X g KCl 100 g H2O 300 g H2O X = 126g KCl
How much H2O is required to just dissolve 200 g NaNO3 at 20C? 88 g NaNO3 = 100 g H2O 200 g NaNO3 X g of H2O X = 227.3 g H2O
On the line – saturated (full, cannot hold any more solute • Below the line – unsaturated (can hold more solute) • Above the line – supersaturated (holding more solute then it should – very unstable)
Saturated Solution Is in equilibrium between solid particles dissociating into ions and ions forming crystals Cl- (aq)
Supersaturated Solution very unstable(this picture is showing the addition of 100 g of glucose to 100ml of water at 250C) Note: at 250C, only 91g of glucose will dissolve in 100 ml of water Let’s see what happens
Precipitation problems • A saturated solution of KNO3 is prepared in 100 g of water at 50C and then cooled down to 10C. How much KNO3 will precipitate?
88 g KNO3 in 100 g H2O at 50C 20 g KNO3 in 100 g H2O at 10C 88 g – 20 g = 68 g KNO3 precipitates