CHM1046 EXAM 1 SOLID Definite Definite High NOT Compressibility Motion of atoms Vibrate LIQUID Definite High Slightly GAS Indefinite Low YES Takes shape of container Takes shape vol of container Slide above each other v high motion Intermolecular Forces forces that determine the phase S or L of molecules exists b w different molecules weaker than INTRAmolecular forces Hvap Hfus Hsub BP Surface Tension Viscosity Induced Dipole Induced Dipole Dispersion exists in all molecules o strength larger the electron larger the dispersion force o 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 molecules o depends on ionic charge and size o strength cation anion Ion Ion b w ionic molecules o forces increase as ionic charge increases and decreases as ionic radius increases 11 1 Volume Shape Density 11 2 Ion Induced Dipole b w ionic and NONpolar molecules o 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 atoms o depends on interaction b w electrons on the EN atom and H o BP stronger intermolecular forces increase BP Van Der Waals Forces 11 3 Surface 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 temp Water is special very polar H bonds ice is less dense than liquid water Oxygen makes 2 H bonds with H2 o each H makes 1 H bond with O 11 4 11 7 Crystalline solid rigid and long range order possesses ions that occupy specific predictable positions Unit Cell basic repeating structural unit of a crystalline solid Amorphous solid lacks 3D geometry glass optically transparent fusion product of inorganic materials that have cooled to a rigid state without crystallizing o most found o 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 nature Cubic 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 cell Relationship between Edge Length a Atomic Radius r SCC a 2r BCC a 4r 3 FCC a 8r 11 6 Crystals Ionic Compounds NOT ionic bonds cations anions o when they melt dissolve in solution they WILL CONDUCT electricity o 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 Fe Hard Soft Melting Point Type of Force Good Poor Cond Molecular Soft Low Ionic Hard High Covalent Metallic Hard High Covalent Soft to Hard Low to High Metallic Intermolecular H Bond D D Disp Ion ion Electrostatic forces Poor Poor Poor Good Ionic Force H Bond Dipole Dipole Dispersion 11 8 Solid phase molecules are fixed they are in order Liquid phase molecules have more freedom still have are in a certain order Gas phase molecules are random FREE Equilibrium Vapor Pressure vapor pressure measured when a dynamic equilibrium exists b w condensation and evaporation o any liquid has an equilibrium with its gas form o H2O l H2O g at room temp Dynamic Equilibrium Rate of Condensation Rate of Evaporation Vapor 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 atm Molar heat of Vaporization Hvap energy required to vaporize 1 mole of a liquid at its BP 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 forces Solid liquid Equilibrium melting point of a solid or the freezing point of the liquid is the temp at which the solid and liquid phases coexist in equilibrium H2O s H2O l Clausius Clapeyron equation lnP1 P2 Hvap R 1 T1 1 T2 R 8 314 J K mol Molar heat of Fusion Hfus is the energy required to let 1 mole of a solid substances at its freezing point Calculate energy absorbed released Hsub Hfus Hvap Hfus Hmelting 333 55 J g Hvap 2257 J g Ex 10 ice 110 vapor 1 mc T 2 start A 10 ice 200g 0 ice spec heat 2 05 J g K 3 2 05 J g K 200 g 10 K 4 100 J 4 A B 0 ice 0 water Hfus 333 55 J g 5 333 55 J g 200 g 67 110 J 6 B C 0 water 100 water spec heat 4 178 J g K 7 4 178 J g K 200 g 100 K 83 560 J 8 C D 100 water 100 vapor Hvap 2257 J g 9 2257 J g 200 g 451 400 J 10 D finish 100 vapor 110 vapor spec heat 1 89 J g K 11 1 89 J g K 200 g 10 K 3 780 J 12 4 100 J 67 110 J 83 560 J 451 400 J 3 780 J 609 950 J start finish 11 9 or gas Phase Diagram summarizes the conditions at which a substance exists as a solid liquid Triple 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 decreases 12 1 Solutions are made up of solute substance that is being dissolved solvent solution the solute is dissolved in classified according to o types of solute solvent o 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 supersaturated contains max amount of solute a saturated solution can have Three types of solutions o liq liquid o solid liquid o gas liquid 12 2 What happens to the intermolecular forces when we form a solution in order to dissolve a solute in a solvent o solute solute interaction break up o solvent solvent interaction break up o form solvent solute interaction For breaking and forming bonds H1 solvent solvent H1 0 endothermic H2 solute solute H2 0 endothermic H3 solvent solute H3 0 exothermic Hsol H1 H2 H3 H3 is either or To …
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