CHEM 122 11th EditionExam # 2 Study Guide Lectures: 10 - 16Lecture 10 (February 10th )- Solutions: a homogeneous mixture uniformly mixed on the molecular level.- Alloys: solid metal solutions- Components: Substances in a solution- Concentration of Solutions:o Concentration can either be qualitative or quantitative.o Qualitative: dilute solution (little solute) or concentrated solution (lots of solute)o Quantitative: Exact amount of solute in a solvent or solute.o Mass Percentage: Mass of solutetotal solution massx 100 %- Parts Per Million (ppm): Mass of solutetotal solution massx 106- Parts Per Billion (ppb): Mass of solutetotal solution massx 109- Mole Fraction: Moles solutetotal moles solution=mole fraction(XA❑)<1o Has no units- Molarity: Moles soluteliter solution=Molarity(M )o Mol/Lo Based on solution volume- Molality: Moles solutekg solution=Molality(m)Solution Formation- Driving forces for solution formation:1. Tendency toward randomness, becoming increasingly disordered2. Enthalpy change in forming a solution, releasing energy or adding energy.- Solvation: interaction of the solvent with a dissolved soluteo With water this interaction is called hydration- Hydrate: Sphere of molecules surrounding the solute.Solution Process1. Solvent molecules are separated, requiring energy an endothermic process (∆ H1¿2. Solute particles are separated, requiring an endothermic process (∆ H2¿3. The solute-solvent molecules interact, releasing energy, an exothermic process (∆ H3¿4. Energy change equation for the process:a.3¿∆ HSoln=∆ H1+∆ H2+∆ H¿b. If 3¿∆ H¿¿¿ then the solution process is exothermicc. If 3¿∆ H¿¿¿ then the solution process is endothermicd. If the solution process is too endothermic then the solution will not dissolve and a solution is not formedLecture 11 (February 9th )Solubility: The maximum amount of solute that will dissolve in a given quantity of solvent at a given temperature- Saturated Solution: dissolving process proceeds until no further solute dissolves- Dynamic equilibrium: no net change in the concentration of dissolved solute.- Supersaturated Solution: a solution that has more dissolved solute than the solubility permits.Solubility of Two Liquids:- Miscible: two liquids are soluble in all proportionso Ex: water and ethanol mix completely.- Immiscible: liquids that aren’t solubleo Ex: water and oil. Oil sits on top of water because they don’t mix.Liquids that are miscible have similar intermolecular forces and immiscible don’t.Solubility of Gases in Liquids:- Gas dissolve in liquids to form solutions. For a gas molecule to dissolve in a liquid it must strike the surface of the liquid and get captured by the liquid.- As partial pressure of the gas increases, there are more collisions of gas molecules with the surface resulting in more gas dissolving.- Henry’s Law: C=k Pgo C: solubility of the gas in the solvent (g/L)o Henry’s Law ConstantoPg: Partial pressure of the gas over the solution (atm, torr)- Solubility at two partial pressures: C1P1=c2P2Lecture 12 (February 11th )Temperature effects on gas solubility:- Solubility of a gas in a liquid decreases with increasing temperature.Colligative Properties of Solutions: physical properties of solutions that depend only on the concentration of solute particles; not on the chemical identity of the particles.- Vapor Pressure: pressure exerted by the vapor when the liquid and vapor state is in equilibrium, only happened in a closed container.Nonvolatile: Particle that doesn’t have a vapor pressure, all ions are nonvolatileo Raoult’s Law: Gives the vapor pressure of a solution containing nonvolatile solute.oPsoln=XsolventPsolventoPsoln: Vapor pressure of the solutionXsolvent: Mole fraction of the solventPsolvento: Vapor pressure of pure solvento Vapor Pressure lowering Equation:o∆ P= XsolutePsolvento=PsolventoPsolution o Total vapor pressure of the solution:oPtotal=XAPAo+XBPBo- Boiling Point Elevation: the boiling point of solution with nonvolatile solutes is higher than that of the pure solvent.o Equation for boiling-point-elevation: ∆ Tb=Kb∗m o∆ Tb: Boiling point increase (∆ C❑o)oKb: Boiling-point-elevation constant (C❑o/m ¿om: molality of the solute particlesLecture 13 (February 13th)Freezing-Point-Depression:- When a solution freezes, crystals of pure solvent generally form. A solute is not usually soluble in a solid crystalline solvent. This lowers the freezing point of the solution compared to just freezing the solvent.- Freezing Point of the Solution: the temperature that crystals of pure solvent begin to form.- Equation for freezing point depression: ∆ Tf=Kf∗mo∆ Tf:decrease∈freezing pointoKf: Freezing point depression constantom: Molality of the solute particlesOsmosis and Dialysis:- Osmosis: passage of solvent molecules from a dilute solution to a more concentrated solution- Dialyzing membrane: a membrane that allows water and small solute particles to pass through- Osmotic membrane: membrane that only allows small solvent molecules to pass, blocks solute molecules.- Osmotic Pressure: pressure required to stop solvent flow from pure solvent into a solution. (π ¿- Osometer: a device for measuring osmotic pressure.- Osmotic Pressure Equation: π =MRTo M: molarity of the solutiono R: ideal gas constant (.0821)o T: Kelvin temperature- Hypotonic: solution with lower osmotic pressure and high solute concentration. Solvent flows out of the cell and causes the cell to shrivel- Hypertonic: solution of higher osmotic pressure and low solute concentration. Solvent flows into the cell and caused the cell to swell and burst- Isotonic: when the solutions have the same osmotic pressureLecture 14 (February 18th)Chemical Kinetics: speeds of chemical reactions take place.- What affects the Rate of reactions:1. Chemical nature of the reactants2. Ability of the reactants to collide3. Surface area of the solid reactant4. Concentration of the reactant5. Temperature6. Catalyst: a substance that can speed up a reaction.- How to measure rate:ochange∈moles productchange∈time=∆ moles product∆ t - Change in moles product:o Mol product (final time) – mol product (initial time)o When products are formed the product is positiveo When reactants are consumed, change in the reactant is negative- Average rate of a chemical reaction:oAverage Rate=change∈molchangetRate law equation: relates the rate of a reaction to the concentration of