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CHEM 126 Chapter 12
CHEM 126 Final
Question | Answer |
---|---|
Ion-Dipole force | - strength depends on charge density & size of ion (stronger as charge of ion or magnitude of dipole increases) - most commonly found in solutions - positive (cation) attracts partially negative & anion (anion) attracts partially negative - EX: h20 + N |
Dipole - Dipole force | attractive forces between positive end of 1 polar molecule & negative end of another polar molecule - weaker than ionic & covalent bonds (only significant when touching) - EX: I + Cl |
Ion Induced Dipole force | - ion induces a dipole of an atom/in a nonpolar molecule (disrupt e- arrangement in nonpolar specieis --> form a dipole) - EX: Fe+2 induces 02 |
Dipole Induced Dipole force | - polar molecules induce a dipole in an atom/in a nonpolar molecule (disrupt e- arrangement in nonpolar species) - EX: ethanol (polar) induces I2 (nonpolar) |
Hydrogen Bond | - strongest bond - H + (N, O, or F) - H has high + charge density & high - charge density |
Dispersion Forces | - NON POLAR molecules induce dipolse on each other - ex: oils, gas, unfamiliar forms of substance - polarizable e-clouds |
range of attraction strength | 1. ionic 2. covalent 3. ion-dipole 4. hydrogen bonding 5. dispersion forces 6. dipole-dipole 7. ion-induced dipole 8. dipole-induced dipole |
properties of a solid | high intermolecular forces, low KE, high PE |
properties of a liquid | medium intermolecular forces, equal KE and PE |
properties of a gas | low intermolecular forces, high KE and low PE |
melt/fusion | solid to liquid (increase temp) q = n(∆H°fus) |
freeze | liquid to solid (decrease temp) q = n(-∆H°fus) |
vaporize/boil | liquid to gas (increase temp) q = n(∆H°vap) |
condensation | gas to liquid (decrease temp) q = n(-∆H°vap) |
sublimation | solid to gas (increase temp) |
deposition | gas to solid (decrease temp) |
vapor pressure | - liquid gas equilibium - high vapor pressure --> evaporate more quickly - system will adjust rates of vapor/condensation to return to same vapor pressure |
boiling point | vapor pressure = external, varies with altitude due to pressure change |
melting/freezing point | - solid liquid equilibrium, pressure has no effect |
PHASE DIAGRAM | - line between two phases = where at equilibrium - triple point = all at equilibrium - critical point = when equilibrium between liquid and gas becomes non-existent and turns into state in between both |
surface tension | -energy required to increase the surface area (J/m2) - increase SA -> molecules move up to exterior by breaking attractions in the interior - stronger intermolecular forces -> more energy to increase SA -> more surface tension |
capillarity | - rising of a liquid against the pull/gravity through a narrow space - competition between IMAFs within a liquid & those between the liquid & tube walls |
concave up vs. concave down meniscus | - UP: IMAFs are stronger within substance vs between the substance & glass - DOWN: IMAFs from substance and glass form adhesive bonds with glass, cohesion forces between glass & substance |
polar & nonpolar surface interaction | - adhesive forces between nonpolar (dipole induced dipole) are weaker than polar (H-bonds)-> pull away - EX: h20 & non polar surface |
Viscosity | - resistance of a fluid to flow - results from IMAFs that impeded movement of molecules around and past each other - liquid > gas(more places for IM forces to act) |
external effects on viscosity | - TEMP: v decreases with increased temp - MOLECULAR SHAPE: small/sphere - little contact, pour easily VS. long/large - more contact & pour slower |
bond length & covalent radius | - bond length: between two bonded atoms in the SAME MOLECULE - 1/2 bond length = covalent raidus |
van der waals distance & radius | - raidus: distance between nuclei of identical nonbonded atom, always larger than covalent radius - radii decreases across a period and increases down a group |