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Solutions. Definitions Types of Solution Solutions, Colloids, Suspensions Process of Dissolving Rate of Solution Concentration Solubility. Definitions. Homogenous Mixture – two or more substances which have the same composition throughout; uniform; in the same state of matter
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Solutions Definitions Types of Solution Solutions, Colloids, Suspensions Process of Dissolving Rate of Solution Concentration Solubility
Definitions • Homogenous Mixture – two or more substances which have the same composition throughout; uniform; in the same state of matter • Solutions, Colloids, Suspensions • Heterogeneous Mixture – two or more substances which have a mixture in which the ingredients are not uniformly dispersed. • Fruity Pebbles
Definitions • Solution - homogeneous mixture of two or more substances Solute - substance being dissolved, present in smaller amount Solute particles very small Solvent - present in greater amount
Definitions Solute - KMnO4 Solvent - H2O
Types of Solutions • Based on state of solvent. • All solid-liquid-gas combos are possible. • EX: dental amalgam (alloy of silver, mercury, etc.) • liquid solute, solid solvent • solid solution
Types of Solutions air O2 gas and N2 gas gas/gas soda CO2 gas in water gas/liquid seawater NaCl in water solid/liquid brass copper and zinc solid/solid
Learning Check SF1 (1) element (2) compound (3) solution A. water 1 2 3 B. sugar 1 2 3 C. salt water 1 2 3 D. air 1 2 3 E. tea 1 2 3
Solution SF1 (1) element (2) compound (3) solution A. water 2 B. sugar 2 C. salt water 3 D. air 3 E. tea 3
Learning Check SF2 Identify the solute and the solvent. A. brass: 20 g zinc + 50 g copper solute = 1) zinc 2) copper solvent = 1) zinc 2) copper B. 100 g H2O+5 g KCl solute = 1) KCl 2) H2O solvent = 1) KCl 2) H2O
Solution SF2 A. brass: 20 g zinc + 50 g copper solute = 1) zinc solvent = 2) copper B. 100 g H2O+5 g KCl solute = 1) KCl solvent = 2) H2O
Dissolving • Solvation • occurs at the surface of the solute • solvent particles surround solute particles (+/- attraction) • solute particles are pulled into solution
Dissolving NaCl dissolving in water
NONPOLAR NONPOLAR POLAR POLAR “Like Dissolves Like” • Detergents • polar “head” with long nonpolar “tail” • can dissolve both types
Learning Check SF4 Which of the following solutes will dissolve in water? Why? 1) Na2SO4 2) gasoline 3) I2 4) HCl
Like dissolves like A ____________ solvent such as water is needed to dissolve polar solutes such as sugar and ionic solutes such as NaCl. A ___________solvent such as hexane (C6H14) is needed to dissolve nonpolar solutes such as oil or grease.
Solution SF4 Which of the following solutes will dissolve in water? Why? 1) Na2SO4 Yes, polar (ionic) 2) gasoline No, nonnpolar 3) I2 No, nonpolar 4) HCl Yes, Polar
Colloids • Have medium size particles • Cannot be filtered • Separated with semipermeable membranes • Scatter light (Tyndall effect)
Examples of Colloids • Fog • Whipped cream • Milk • Cheese • Blood plasma • Pearls
Suspensions • Have very large particles • Settle out • Can be filtered • Must stir to stay suspended
Examples of Suspensions • Blood platelets • Muddy water
Rate of Solution - Solids • Solids dissolve faster (have greater solubility) with... • more stirring • small particle size(increased surface area) • high temperature
Temperature and Solubility of Solids Temperature Solubility (g/100 g H2O) KCl(s) NaNO3(s) 0° 27.6 74 20°C 34.0 88 50°C 42.6 114 100°C 57.6 182 The solubility of most solids (decreases or increases ) with an increase in the temperature.
Temperature and Solubility of Solids Temperature Solubility (g/100 g H2O) KCl(s) NaNO3(s) 0° 27.6 74 20°C 34.0 88 50°C 42.6 114 100°C 57.6 182 The solubility of most solids increases with an increase in the temperature.
Rate of Solution - Gases • Gases dissolve faster and have great solubility if... • no shaking or stirring • high pressure above surface • low temperature
Temperature and Solubility of Gases Temperature Solubility (g/100 g H2O) CO2(g) O2(g) 0°C 0.34 0.0070 20°C 0.17 0.0043 50°C 0.076 0.0026 The solubility of gases (decreases or increases) with an increase in temperature.
Temperature and Solubility of Gases Temperature Solubility (g/100 g H2O) CO2(g) O2(g) 0°C 0.34 0.0070 20°C 0.17 0.0043 50°C 0.076 0.0026 The solubility of gases decreases with an increase in temperature.
Concentration • Concentrated solution • large amount of solute • Dilute solution • small amount of solute
Concentration • % by Volume: usu. liquid in liquid • EX: 10% juice = 10mL juice + 90mL water • % by Mass: usu. solid in liquid • EX: 20% NaCl = 20g NaCl + 80g water • % solution = mass of solute x 100 • mass of solution
UNSATURATED SOLUTION more solute dissolves SATURATED SOLUTION no more solute dissolves SUPERSATURATED SOLUTION becomes unstable, crystals form Concentration concentration
Solubility Solubility maximum grams of solute that will dissolve in 100 g of solvent at a given temperature varies with temperature based on a saturated solution g of solute 100 g water
Learning Check S1 At 40C, the solubility of KBr is 80 g/100 g H2O. Indicate if the following solutions are (1) saturated or (2) unsaturated A. ___60 g KBr in 100 g of water at 40C B. ___200 g KBr in 200 g of water at 40C C. ___25 KBr in 50 g of water at 40C
Solution S1 At 40C, the solubility of KBr is 80 g/100 g H2O. Indicate if the following solutions are (1) saturated or (2) unsaturated A. 2 Less than 80 g/100 g H2O B. 1 Same as 100 g KBr in 100 g of water at 40C, which is greater than its solubility C. 2 Same as 60 g KBr in 100 g of water, which is less than its solubility