Chapter 13.2 Pgs. 390-393 Haeri Lee, Natalie Curtis, Jen Deasy

Chapter 13.2

Pgs. 390-393

Haeri Lee, Natalie Curtis, Jen Deasy

Kinetic Theory

• Kinetic theory says particles are in constant motion, but particles of a liquid are attracted to each other.

• Intermolecular Attractive Forces: keep particles close together, reduce amount of space between particles. – Motion and attraction helps determine physical

properties. – Why liquid has a definite volume.

Vaporization

• Def: conversion of a liquid into a gas or vapor. • Evaporation: when this occurs on a non-

boiling liquid.– Liquid evaporated faster when heated: KE of

particles increases, and particles w/ highest KE escape first. As this occurs, liquid’s temperature decreases.

Liquid Vapor (Gas)Evaporation

Condensation

Vapor Pressure

• Def: measure of force exerted by a gas above a liquid in a sealed container.– In constant VP, equilibrium btw liquid & vapor where

evaporation of liquid = condensation of vapor.• KE & VP: An increase in contained liquid

temperature increases vapor pressure bc warmed particles have higher KE so they can escape the surface of the liquid and collide w/ the walls.

As temperature increases, vapor pressure increases

Pressure & Vapor Pressure

• Vapor pressure measured with a manometer; when liquid is added pressure increases due to VP, pushing the mercury in the manometer.– In just air, nothing happens bc pressure is same on

both sides.• Pressure is the force upon an object. Vapor

pressure is the amount of force vapor applies to the liquid in a closed container.