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Chapter 12. Solutions. Solution. Solution- homogeneous mixture of 2 or more substances in a single phase Substances have to be soluble (dissolvable) “If not part of solution, part of precipitate” Solute- dissolved Solvent- does the dissolving
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Chapter 12 Solutions
Solution • Solution- homogeneous mixture of 2 or more substances in a single phase • Substances have to be soluble (dissolvable) • “If not part of solution, part of precipitate” • Solute- dissolved • Solvent- does the dissolving • If both liquid in equal amount, can’t say which is which
Types of solutions • Alloys- Brass (Zn + Cu), Sterling Ag (Ag + Cu) • G in G • G in L • L in L • L in S • S in L • S in S • Examples of each will be discussed
Mixtures • Heterogeneous • Either colloid or suspension
Colloid • Colloid • Middle size particles • 1 nm – 1000 nm • Can’t be filtered • Does not settle out over time • Muddy water • Mayo – oil, water, egg yolk • Tyndall Effect- light scatters, appears “foggy” (movie theater projector light stream)
Suspension • Largest particle size • Particles settle out over time • Over 1000 nm • Can be filtered • Blood- rigor mortis, centrifuge • Milk- layers of cream • Soil- rock layers • Other examples
Electrolytes • Solutes can be electrolytes or nonelectrolytes • Electrolytes- dissolve in water and conduct electricity • Nonelectrolytes cannot conduct electricity • Examples of each • Review of dipoles, van der Waals forces
How to affect rate of dissolution • Increase surface area of solute • Agitate • Heat • What does each do to the solute • Translation
Solution equilibrium • Dissolution and crystallization occur at the same rate • See double arrow (Scarecrow in Wizard of Oz giving directions) • How we push it to one side- Le Chatlier’s Principle
Saturation • Saturated- maximum amount of solute dissolved • Unsaturated- can add more solute • Supersaturated- more than saturated, add one flake and it crystallizes (seeding) • Boil saturated to make supersaturated • Examples
Solute-Solvent interactions • Like dissolves like- polar vs. nonpolar • Hydration- water breaks solute • L + L- immiscible if don’t mix • L + L- miscible if mix • Examples • Increase Pressure, go to L phase
Gases • Henry’s Law- solubility of gas is directly proportional to the partial pressure of gas on liquid surface • Rapid escape of gas from liquid- effervescence • Increase temperature, decrease gas solubility
Liquid and solid • Can’t predict liquid solubility if change temp. • Increase temperature, increase solid solubility • Enthalpy chart of dissolving 2 solids, enthalpy released
Molarity • M = mole solute/L solution • M1V1 = M2V2 • Example problems
molality • m = moles solute/kg solvent • Example problems
Normality • Dissolvable hydrogens/L solution
Mole ratio • X = moles solute/moles solvent
V/V ratio • Volume solute/volume solvent