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Vaporization
Vaporization
Evaporation in an open container. Condensation rate will probably never be as high as evaporation rate.
Vaporization
VaporizationEvaporation in a closed container. Condensation rate will eventually equal evaporation rate.
Vaporization
What factors affect the rate of evaporation?
How Temperature Affects Evaporation Rate
What factors affect the rate of evaporation?
Temperature
Surface area
Strength of intermolecular attractive forces
What factors affect equilibrium vapor pressure?
What factors affect equilibrium vapor pressure?
Temperature
Strength of intermolecular attractive forces
Boiling
Boiling
An Exponential Equation for Pressure
• P = β exp(-ΔHvap /RT)
• ln P = ln β + ln exp(-ΔHvap / RT)
• ln P = ln β - ΔHvap / RT
• ln P = ln β - (ΔHvap / R) (1 / T)
• Y = b + mX
• Plot ln P against 1 / T. Slope = -ΔHvap/R
• ΔHvap = -R . Slope where R = 8.314 J / K mol
The 2-Point Clausius-Clapeyron Equation
• ln P = ln β - (ΔHvap / R) (1 / T)
• ln P2 = ln β - (ΔHvap / R) ( 1 / T2)
• Ln P1 = ln β - (ΔHvap / R) (1 / T1)
• ln P2 - ln P1 = (ΔHvap / R) (1 / T1 - 1 / T2)
• Ln (P2 / P1) = (ΔHvap / R) (1 / T1 - 1 / T2)