Section 2: Gas Behavior

• Objective: define the relationship

between volume and pressure of a gas

state Boyle’s Law define the relationship

between pressure and temperature of a gas

define the relationship between volume and the temperature of a gas and state Charles’s law What gas law explains why

thishot air balloon rises?

Key Terms

• temperature– The measure of the average kinetic energy of

the particles in a substance.

• pressure– The force exerted on a surface divided by the

total area over which the force is exerted

• Boyle’s Law– The relationship between the pressure and

volume of a gas at constant temperature; when volume increases, pressure decreases.

• Charles’s Law– The relationship between the temperature and

volume of a gas at constant pressure; when temperature increases, volume increases.

Three properties of gases

Volume: gaseshave the same volume as theircontainer.

Temperature: average kinetic energy of the molecules.

Pressure: force/area

Relationship between pressure & volume of a gas.

The volume of a fixed amount of gas varies inversely withThe pressure of the gas.

Boyle’s Law

Boyle’s Law: when the pressure of a

gas is increased at constant temperature,

the volume of the gas decreases. When

The pressure is decreased, the volume

increases.

Relationship between pressure and temperature

Gay-Lussac’s law: When the temperature of a gas at a constant volume is increased, thepressure of the gas increases. When the temperature is decreased, the pressure of the gasdecreases.

Why must truck drivers monitor and adjust tire pressure on long trips, especially during the hot summer months?

Tires on 18-wheelers arevery large and stiff.

The volume of thesetires does not vary much.

Relationship between volume and temperature

A direct relationship exists between volume and temperature.

Charles's Law: when the temperature of a gas is increased at constant pressure, its volume increases. When the temperature ofa gas decreased its volume decreases.

The volume of a balloon is less in a beaker of ice water than if the same balloon is in a beaker of hot water. Why does this happen?