CHM1046 EXAM 111.1SOLID LIQUID GASVolume Definite Definite IndefiniteShape Definite Takes shape of containerTakes shape/vol. of containerDensity High High LowCompressibility NOT Slightly YESMotion (of atoms) Vibrate Slide above each otherv. high motion11.2Intermolecular Forces: forces that determine the phase (S or L) of molecules; exists b/w differentmolecules; weaker than INTRAmolecular forces; ΔHvap, ΔHfus, ΔHsub-BP, Surface Tension, Viscosity• *Induced Dipole-Induced Dipole (Dispersion): exists in all moleculeso strength: larger the electron, larger the dispersion forceo larger the molecular mass, larger the dispersion force• Dipole-dipole: b/w polar covalent molecules• *Dipole-Induced Dipole: b/w polar and nonpolar molecules• Ion-dipole: b/w ionic and polar moleculeso depends on ionic charge and sizeo strength: cation>anion (+,-)• Ion-Ion: b/w ionic moleculeso forces increase as ionic charge increases and decreases as ionic radius increases• *Ion-Induced Dipole: b/w ionic and NONpolar moleculeso depends on charge, size, and polarizability (incr. with the incr. in # of e- or MW)• Hydrogen Bonding (special type of dipole-dipole): b/w H atoms in a polar bond (N-H, O-H, F-H) and electronegative (O,N,F) atomso depends on interaction b/w electrons on the EN atom and HoBP- stronger intermolecular forces increase BP*Van Der Waals Forces11.3Surface Tension- the stronger the intermolecular force, the higher the ST• on top/surface- increase Surface Area• in middle- different directions• Cohesion- attraction b/w like molecules (H20 & H20)• Adhesion- attraction b/w unlike molecules (H20 & glass)Viscosity- stronger intermolecular forces increase viscosity; decrease with increase in tempWater is special • very polar = H-bonds• ice is less dense than liquid water• Oxygen makes 2 H-bonds with H2o each H makes 1 H-bond with O11.4, 11.7Crystalline solid: rigid and long-range order; possesses ions that occupy specific(predictable) positions• Unit Cell: basic repeating structural unit of a crystalline solidAmorphous solid: lacks 3D geometry• glass: optically transparent fusion product of inorganic materials that have cooled to a rigid state without crystallizingo most foundo glass with different colors have different metal ions in them (Green-Fe2O, Fe2+, Blue-Co2+ or Cu2+)**different crystals differ in unit cells; in nature, there are 7 basic unit cell structures• cubic: typically found in natureCubic: 3 types-Coordination Number: number of closest atoms to central atom• Simple Cubic: 1 atom; Coordination #: 6• Body-centered: 2 atoms; Coordination #: 8• Face-centered: 4 atoms; Coordination #: 12-Closest Packing- hexagonal (HCP) and Cubic (CCP)o the closest cubic packing unit is a face-centered cubic cellRelationship between Edge Length (a) & Atomic Radius (r)• SCC: a=2r• BCC: a=4r/√3• FCC: a=√8r11.6Crystals• Ionic: Compounds, NOT ionic bonds (cations +anions)o when they melt/dissolve in solution, they WILL CONDUCT electricityo CsCl ZnS CaF2 NaCl• Covalent: covalent bonds/intramolecular (atoms)o Diamond Graphite C60 SiO2• Molecular: (molecules)o Pure Ice Pure Water Iodine CO2• Metallic: (metal atoms)o Cu Na FeHard/Soft Melting Point Type of Force Good/Poor Cond.Molecular Soft Low Intermolecular, H-Bond, D.D, DispPoorIonic Hard High Ion-ion, Electrostatic forcesPoorCovalent Hard High Covalent PoorMetallic Soft to Hard Low to High Metallic GoodIonic Force > H-Bond > Dipole-Dipole > Dispersion11.8 Solid phase: molecules are fixed • ≡they are in orderLiquid phase: molecules have more freedom• ≡still have/are in a certain orderGas phase: molecules are random• ≡FREEEquilibrium Vapor Pressure: vapor pressure measured when a dynamic equilibrium existsb/w condensation and evaporationo any liquid has an equilibrium with its gas formo H2O (l) ↔ H2O (g) at room tempDynamic Equilibrium: • Rate of Condensation = Rate of EvaporationVapor Pressure: pressure exerted by vapor at equilibrium with its liquid (at certain temp)• VP ↑ when temp ↑• the higher the intermolecular forces in a liquid, the lower the VP• the lower the VP, the more heat needed to boil the liquid• at boiling (change of L G), VP should equal the pressure surrounding• normal BP is the temp when VP reaches 1 atmMolar heat of Vaporization: (ΔHvap) energy required to vaporize 1 mole of a liquid at itsBP• constant for every liquid• VP ↑ with ↑ of temp• VP ↑ with ↑ intermolecular forces Boiling Point: temp at which the (equilibrium) vapor pressure of a liquid is equal to the external pressure (when VP= 1atm)• BP ↑ with ↑ of intermolecular forcesSolid-liquid Equilibrium: melting point of a solid or the freezing point of the liquid is thetemp at which the solid and liquid phases coexist in equilibrium • H2O (s) ↔ H2O (l)Clausius_Clapeyron equation: • lnP1/P2 = -ΔHvap/R * (1/T1 – 1/T2)• R = 8.314 J/K·molMolar heat of Fusion: (ΔHfus) is the energy required to let 1 mole of a solid substances atits freezing pointCalculate energy absorbed/released ΔHsub = ΔHfus + ΔHvap• ΔHfus = ΔHmelting = 333.55 J/g• ΔHvap = 2257 J/gEx. -10º ice 110º vapor1. mcΔT2. (startA) -10º ice 200g 0º ice (spec. heat = 2.05 J/g·K)3. 2.05 J/g·K * 200 g * 10º K = 4,100 J4. (AB) 0ºice 0ºwater (ΔHfus = 333.55 J/g)5. 333.55 J/g * 200 g = 67,110 J6. (BC) 0ºwater 100ºwater (spec. heat = 4.178 J/g·K)7. 4.178 J/g·K * 200 g * 100º K = 83,560 J8. (CD) 100ºwater 100ºvapor (ΔHvap = 2257 J/g)9. 2257 J/g * 200 g = 451,400 J10. (D finish) 100ºvapor 110ºvapor (spec. heat = 1.89 J/g·K)11. 1.89 J/g·K * 200 g * 10º K = 3,780 J12. 4,100 J + 67,110 J + 83,560 J + 451,400 J + 3,780 J = 609,950 J (startfinish)11.9Phase Diagram: summarizes the conditions at which a substance exists as a solid, liquid,or gasTriple Point: intersection on a phase diagram where three phases coexist in equilibrium(where all three lines meet on the diagram)• As pressure increases, BP/FP decreases12.1Solutions are made up of:• solute: substance that is being dissolved• solvent: solution the solute is dissolved in• classified according to:o types of solute & solvento amount of solutes in solvent (3 types) unsaturated: contains solute < max amount the given solvent can dissolve at certain temp saturated: contains max amount of solute in a given solvent at certain temp
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