Kinetic Molecular Theory (KMT)

Kinetic Molecular Theory (KMT)

Kinetic Molecular Theory (KMT)

States of Matter Solid

Particles close together May only vibrate

Liquid Particles not as close together Particles may move past each other, but

attracted to each other Gas

Particles far apart Particles may move past each other, NOT really

attracted to each other

States of Matter Solid

Particles close together May only vibrate

Liquid Particles not as close together Particles may move past each other, but

attracted to each other Gas

Particles far apart Particles may move past each other, NOT really

attracted to each other

• Particles close together

• May only vibrate

• Particles close together

• May only vibrate

SolidSolid

Liquid• Particles not as close

together • Particles may move

past each other, but attracted to each other

Gas• Particles far apart• Particles may move

past each other, NOT really attracted to each other

Liquid• Particles not as close

together • Particles may move

past each other, but attracted to each other

Gas• Particles far apart• Particles may move

past each other, NOT really attracted to each other

LiquidLiquid

GasGas

Molecules Cause Pressure

Kinetic Molecular Theory

Particles of matter are ALWAYS in motion

Volume of individual particles is zero. Collisions of particles with container

walls cause pressure exerted by gas.

Particles exert no forces on each other.

Average kinetic energy µ Kelvin temperature of a gas.  

Measuring Pressure

The first device for measuring atmospheric pressure was developed by Evangelista Torricelli during the 17th century.The device was called a “barometer”

Baro = weight Meter = measure

An Early Barometer

The normal pressure due to the atmosphere at sea level can support a column of mercury that is 760 mm high.

PressureIs caused by the collisions of molecules with

the walls of a container is equal to force/unit area SI units = Newton/meter2 = 1 Pascal (Pa) 1 atmosphere = 101,325 Pa 1 atmosphere = 1 atm = 760 mm Hg = 760

torr