 Kinetic= motion  All matter consists of small particles  The molecules are in constant, random, rapid motion  All collisions are elastic (no net loss of energy)

 As temperature increases, the molecules velocity increases, increasing the pressure on the container.

 The average distance traveled between collisions.  An oxygen molecules will collide with other molecules 4.5 billion times per second!

 The temperature of a substance is a measure of the average kinetic energy of its particles.  Absolute zero – the temperature at which molecular motion stops ( o C)

 Caused by gas molecules colliding with the sides of a container  Force per unit area  Units: 1 atm = kPa = 760 mmHg = 760 torr

 How many mmHg is in one kPa? 7.5 mmHg

 Open Manometer – atmosphere exerts pressure on one side and gas sample exerts pressure on the other side ◦ Add if gas pressure is greater ◦ Subtract if air pressure is greater  Closed Manometer (barometer) – vacuum on one side, gas pressure on the other side ◦ No addition or subtraction necessary

StateShapeVolumeCompressible?Flows?SolidDefiniteIndefiniteNoNo LiquidIndefiniteDefiniteNoYes GasIndefiniteDefiniteYesYes

 The pressure produced when vapor particles above a liquid collide with container walls; a dynamic equilibrium exists between the liquid and the vapor.  Vapor pressure increases with temperature.  A substance with weak intermolecular forces has a high vapor pressure and low boiling points. (these are volatile – alcohols, ethers)  A substance with strong intermolecular forces has a low vapor pressure and high boiling point (these are nonvolatile – water, molasses, glycerol)

 Critical Point – above this temperature, no amount of pressure can liquefy it.  Triple Point – all three phases are in equilibrium