Final Review - have low vapor pressures , b/c the molecules...

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Chemistry 302 Vaporization or evaporation – endothermic process which transforms liquid into gas. Requires a lot of energy to overcome the strong IMF’s in liquid. Energy req. to vaporize 1 mole of liquid @ 1 atm is called standard heat of vaporation, ΔH o vap Importance of endothermic nature: water is a coolant. Water has a really high heat of vaporization. Normal boiling point: temperature at which liquid boils at 1 atm. Condensation: process by which vapor molecules re-form a liquid Equilibrium occurs when the rate of condensation = the rate of evaporation. Vapor pressure- pressure of the vapor present at equilibrium. Principally determined by the size of the IMF’s in the liquid. Liquids that have large IMF’s
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Unformatted text preview: have low vapor pressures , b/c the molecules need high energies to escape the vapor phase. At higher temperatures , liquids have higher vapor pressures . Ln (Pvap) = (-Delta Hvap / R)(1/T) + C Ln (K) = (-Delta H standard/R)(1/T) + Delta S/R Ln(P T1,vap / P T2, vap) = (Delta H vap/R)(1/T2 1/T1) Like liquids, solids have vapor pressures as well, especially those that sublime, going directly from solid to gas state without passing through liquid state. Notes from Quest Tests & Homeworks-Decane (C10H22) is the most miscible in benzene (C6H6) because like dissolves like-If going in this direction (Solid Liquid Gas) , Delta S and Delta H are Positive.-Hydrocarbons cannot be dissolved in water-For phase change, use Q = m*c*deltaT , for only phase change but no temp change, use Q = m* c = n * Delta H...
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Final Review - have low vapor pressures , b/c the molecules...

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