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Solutions – Web Site Presentations. Homogeneous vs. heterogeneous Dissolving vs. melting. Theory of Solutions. 9 solute-solvent combinations Solutions, suspensions, colloids, emulsions. Theory of Solutions. Dilute, concentrated, unsaturated, saturated, and supersaturated
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Solutions – Web Site Presentations • Homogeneous vs. heterogeneous • Dissolving vs. melting
Theory of Solutions • 9 solute-solvent combinations • Solutions, suspensions, colloids, emulsions
Theory of Solutions • Dilute, concentrated, unsaturated, saturated, and supersaturated • 4 factors affecting solution formation
Theory of Solutions • Separating solutions into their components • Like dissolves like
Theory of Solutions • Relationship of equilibrium and solubility • Gases are less soluble in liquids at higher temperatures • Why do precipitates form?
Concentration units • Calculating Molarity (M=moles solute/liter solution) • Molality (m=moles solute/kg solvent) Added info! • Mole fraction (XA=mol A/mol total ) • Dilutions (M1V1=M2V2)
Colligative Properties • Properties that depend upon the number of solute particles present but NOT their type • Vapor Pressure Lowering • Boiling Point Elevation • Freezing Point Depression • Osmotic Pressure • Note: 1 mole of sugar dissolved in 1 kg of water will produce 1m sugar solution, but 1 mole of NaCl dissolved in 1kg of water will produce 2 moles of dissolved particles! This is why 1 mole of CaCl2 will lower the freezing point of water more than 1 mole of NaCl
Colligative Properties • Explain Boiling Point Elevation • ∆Tb=iKbm • Explain Freezing Point Depression • ∆Tf=iKfm
Osmotic Pressure / Vapor Pressure Lowering • External pressure which must be applied to stop osmosis • The greater the # particles in solution, the greater the osmotic pressure • π=iMRT where i is the number of dissolved particles, M is molarity, R is the gas constant, and T is the Kelvin Temperature • Vapor pressure is less when solute particles are present because they interfere with the evaporating process • Psoln=XaPa + ….. Where “a” refers to a liquid because you can only have vapor pressure over a liquid