VSEPR: Valence Shell Electron pair Repulsion: Allows to predict the geometry of molecules. -All electrons repel each other. Valence bond theory: bonds form wen atomic orbitals mix to become hybrid orbitals.Trigonal planr= 1s+2p orbital to give three sp2 orbitals.Tetrahedral=1s+3p, to give 4 sp3 orbitals.Pi bonds= side to side overlapSigma bond= head on overlap of sp2 orbitals.Atomic orbitals form MOs spanning the entire molecule (not just between nuclei)x atomic orbitals produce x MOs.Dipole-dipole forces (includes hydrogen bonds) the A-B bond has a permanent dipole. (weaker thancovalent bonds)London dispersion forces: the bond has a temporary dipole, most common for symmetric systems.IMFs are weak because they involve partial charges. Solids strong IMFsLiquids moderate IMFsGases no IMFsWhich has the highest boiling point? HF, HCl, HBr, HIAll have dipole moments, HF highest dipole moment. Strength (high to low)Covalent= 100-400 kj/molHydrogen bond= 4-50Dipole dipoleLondon forcesHydrogen bond: particular type of dipole dipole moment. Very strong , very electronegative. Strong partial charges on H and (N,O,F). Water, HF and NH2 have higher bps because they have H-bonds.Larger molecular mass = more electrons= larger cloud=easier to induce polarization= stronger DFsPolarizability (how readily the electron cloud is distorted)Vapor: gas phase of a substance that is solid or liquid at 25 degrees celcius and 1 atm. Water at room temp, vapor pressure= 25 torr.Higher Vapor Pressure=lower IMF (Patm=Pvap+Phg, Pvap=Patm-PHg)Higher surface area=faster evaporation. Water wants to be at equilibrium (25 torr). Vaporization rates increase with : increased SA, increased T, decrease IMFPvap increases with: increasing T (higher temp, easier to push molecules into gas phase), decreasingIMF strength.Unstable- BO=0Stable- Higher BOWhen the p orbitals from any two atoms combine to form molecular orbitals how many MOs form? 6 #atomic orbitals mixed=#molecular orbitals formed, P orbitals come in sets of 3, so 2=6.Longest bond=weakest, smaller BOBoiling point- temp where Pvap=Patm, the particles have enough energy to break IMFs.High boiling points are due to: STRONG IMFs, large molar mass.Ring = flatRank BPs based off:Molar massShapesIMFsHfusion=amount of energy put into a solid to go from solidliquid. (endothermic, +) 1 mol/solid. CHvaporization: liquid to gas.Heat of vaporization has a larger magnitude than heat of fusion. (IMF issue, when u apply heat to a solid, you don’t have to break every bond)A nonvolatile solute raises a solvent’s boiling point. The solute can be an electrolyte or a nonelectrolyte. ΔTb=Kb*msoluteKf= freezing point depression constantTf=freezing point depressionChapters 10-12, Skip 11.4, 12.3,-12.4A solution of 5g lauryl alcohol in 0.1 kg of benzene freezes at 4.1 degree celcius, what is MM of laurylalcohol? Kf=5.12 degC Tf=5.5 deg/C?Electrolyte or nonelectrolyte? Nonelectrolyte because its an alcohol 5.5-4.5=5.12(5g (g/mol)/.1kg]Osmotic pressure (atm)=MRTHypertonic-out solution more concentrated, water leaves cells= SHRVELSHypotonic-water comes in= BURSTS.Electrolytes: when put in solutions it dissociates into how many moles _____.?Observed value for I is lower than expected due to ion pairing reduces numbers of particles. OP=iMRTΔTb=i*Kb*msoluteΔTb=i*Kb*msolutePsolution=Xsolvent*PsolventMore moles of solute slow down process of vapotization.Higher boiling point: higher molality=larger BPHigher freezing point=less solute smaller