Intermolecular Interactions

01 23045 vaporizaon

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Unformatted text preview: uires work! •  Usually measured in –  mJ/m2 (milliJoule/meter2) –  Cen+poise (10 ­3 Pa*s) Droplets 43 2 E total = πr * E bulk + πr * E surface 3 E bulk < 0 < E surface Small drops are almost all surface and unfavorable. As they grow, the surface area/volume decreases. The maximum is the cri<cal nucleus. Growth becomes spontaneous. NucleaFon and Growth are fundamental processes. ~17 H2O molecules ~1 H2O molecule 7081#)9."' !"#$%&'()*+'&#,')-.'/.01#,2' (#$ ~187 H2O molecules #$ #$ )##$ "###$ !(#$ !'#$ !&#$ !%#$ !"##$ ~60 H2O molecules 54 molecules (~728pm) is the critical radius. Growth becomes spontaneous. (Going downhill = spont.) $)340,'(562' ")##$ (###$ metastability •  Some+mes a phase should form but does not –  This is kine<c stability –  Nuclea+on has not started –  It will eventually. But when? •  Rearrangement of bonds •  Supercooled water but not superheated •  Gases do not supercool (significantly) Pharmaceu+cals •  Many pharmaceu+cals –  Made using metastable zone crystalliza+on Viscosity •  Ability of molecules to flow around each other –  Gases have very low viscosity –  Raising T makes a liquid more gas like –  Raising T lowers viscosity •  Als...
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This note was uploaded on 12/13/2012 for the course CHE 2045 taught by Professor Osegovic during the Fall '12 term at University of South Florida.

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