CHEM 1312H 1nd EditionExam # 1 Study Guide Lectures: 1 - 8Lectures 1 and 2 (1/5 and 1/7)- there exists intermolecular forces between gases, liquids, and solidso ionic forces (ion – ion): Coloumb’s Law states that there is an attraction proportional to the product of the distance between the centers of the two atomso intermolecular (no charges): a) Dipole – Dipole (dip-dip): between polar covalent molecules, or molecules that have a permanent dipole moment b) Hydrogen Bonding (special type of dip-dip): molecules contain one of the highly electronegative atoms Fluorine, Oxygen, or Nitrogen (FON) c) London Dispersion Forces (LDFs): attractions between atoms or uncharged, non-polar molecules such as CH4- the farther you move down a period, the bigger the electron clouds get  increased polarizability (the squishability of the electron cloud)  easier for LDFs to act because dipole moments come about easier when electrons are easier to snatch away - heavier molecules (increased molecular weight) = more LDFs- always present as a forceo intramolecular forces are generally stronger; these forces include ionic, covalent,and metallic forces (to be covered later)Lecture 2 (1/7) and associated readings:- PROPERTIES- Viscosity: resistance of a liquid to flowo depends on the attractive forces between moleculeso for related compounds (such as hydrocarbons), viscosity increases with molecular weighto for any given substance, viscosity decreases with increasing temperature- Surface tension: imbalance of IMFs at the surface leads the molecules there to experience a net inward/downward pull; this reduces the surface area and makes them pack closely together- Capillary action: the rise of liquid up very narrow tubeso binding of similar molecules is called cohesive forces- PHASE CHANGESo every phase change also has an energy change/transfer associated with ito melting is also called fusion: the increased freedom of motion of the particles requires energy, measured by the heat of fusion ΔHfus gas to liquid = condensation liquid to gas = vaporization liquid to solid = freezing solid to liquid = melting/fusion solid to gas = sublimation gas to solid = deposition- heat of vaporization ΔHvap is the energy required to turn liquid to gas- ΔHvap is usually greater than ΔHfus for a substance because the energy that is needed to completely mobilize all participles is greater- HEATING CURVESo enthalpy changes can be calculated from heating curveso- heat in J (used to calculate the slope-y parts of the heating curve, so AB and CD) q = (mass in grams)(specific heat)( ΔT )- heat energy (used to calculate flat parts of curve, so BC and DE) q = (mass in grams)( either ΔHfus or ΔHvap)- CRITICAL TEMPERATURE AND PRESSUREo critical temperature: the highest temperature at which a distinct liquid phase canexisto critical pressure: the pressure required to bring about liquefaction at the critical temperature- VAPOR PRESSUREo the pressure exerted by a vaporo dynamic equilibrium: condition in which two opposing processes occur simultaneously at equal rateso liquids that evaporate readily are volatileLecture 3 (1/9)- Liquid crystals: “hybrids” between solids and liquids so that there is still some movement within the crystal among particles, but there is also enough structure so as to remain a solido a) normal liquido b) nematic liquid crystal (refer to Lecture 3 for illustrations)o c) smectic A liquid crystal (refer to Lecture 3 for illustrations)o d) smectic C liquid crystal (refer to Lecture 3 for illustrations)o molecules align along the long axis to maximize IMFso pitch: distance required for the top layer of molecules in a cholesteric structure to be replicated after a certain number of rotations (refer to Lecture 3 for illustrations) if the pitch is larger, you’re diffracting longer wavelengths of light and vice versa: red lights = longer pitches, blue lights = shorter pitches as you change the temperature, you also change the pitch distance- heat the liquid, pitch gets smaller, turns more blue- cool the liquid, pitch gets longer, turns more red to make a liquid crystal:- you want long, rod-like rigid molecules- you also want strong bonds/attractions (like IMFs) but not too strong of attractions (so no ionic + - charges) that would completely discourage movement in between moleculesLecture 4 (1/12)- SOLIDSo amorphous solids: no long range order; structure is similar to liquid’s, but ions/molecules/atoms don’t have freedom of motion ex, glass, rubbero crystalline solids: 3D order, atoms are arranged in an orderly repeating patterno unit cell: smallest repeating unit of a crystal (building blocks)o crystal lattice: the geometrical pattern of points on which the unit cells are arranged (the building)- OVERVIEW OF THE CLASSES OF SOLIDSo ionic solids (ion – ion forces): composed of cations and anions, held together by mutual electrostatic attractions between cations and anions ex, NaCl, KBr, MgO high melting points and boiling points, typically brittle (when a hammer hits an ionic solid and disrupts the structure, the molecular layers shift laterally and cations with cations and anions with anions come in contact with each other; upon contact, they immediately repel, which results in thebrittle solid breaking and shattering), many dissolve in water o molecular solids (LDF, dip-dip, hyodrogen bonding): composed of molecules held together by IMFs, tend to be soft and have low boiling and melting points ex, ice (composed of H2O), solid CO2 low melting and boiling points, softero covalent network solids (covalent bonding): atoms that are bonded to its neighbor(s) by strong covalent bonds ex, diamond (pure carbon), graphite, SiC high boiling and melting points, typically hard, typically insoluble and very stableo metallic solids (metallic bonding (to be defined)): held together by collectively shared valence electrons (this is what allows it to conduct electricity) high melting points and boiling points, malleable, ductile, good electrical conductorsLecture 5 (1/14) and associated readings- 3D STRUCTURESo primitive cubic lattice: atoms are at all the corners (1 atom total/unit cell)o body centered cubic lattice: lattice points at all 8 corners of the unit cell, along with one at the center of the unit cells (2 atoms total/unit cell)o face centered: all 8 corners, along with at all 6 faces (6 atoms/unit cell)- METALLIC