Behavior of Gases Kinetic Molecular Theory (KMT)

Properties of Gases 1)No definite shape: they take on the shape of their container

Properties of Gases 2) No definite volume: they will expand to fill their container

Properties of Gases 3) Unlike solids and liquids, they can be easily compressed

Kinetic Molecular Theory (KMT) This theory tries to explain why gases behave the way they do. It is model of IDEAL gas behavior.

Kinetic Molecular Theory (KMT) Idea # 1: Gases are made of particles (atoms or molecules) that are in constant random straight-line motion

Kinetic Molecular Theory (KMT) Idea # 2: Gases particles collide with each other and the walls of their container. These collisions are elastic, meaning no energy is lost during the collision, only transferred. These collisions are measured as pressure of the container walls

Elastic Collisions

Kinetic Molecular Theory (KMT) Idea # 3: Gas particles are separated by great distances. Therefore the volume of the individual gas particles is negligible compared the volume of the container.

Kinetic Molecular Theory (KMT) Idea # 4: Gas particles are so far apart they do not attract each other.

Pressure and number of gas particles More particles = higher pressure

Temperature and volume Higher Temperature = bigger volume (if the container has expandable walls so that pressure does not change) WHY? Remember temp = ave kinetic energy Higher temp means the gas particles move faster, hitting the walls of the container harder and pushing it outward

The igloo fiasco

Temperature and Volume Volume Temperature

Temperature and pressure Higher temperature = higher pressure (if walls of container are not exandable) WHY? temp = ave kinetic energy Higher temp means the gas particles are moving faster, hitting the walls of the container harder. This results in more pressure measured on the container walls

Exploding cans…. + = ?

Temperature and Pressure Pressure Temperature

Pressure and Volume Increasing the pressure on a gas in a container will decrease the volume

Pressure and Volume Volume Pressure