Chapter 3 Section 3 The behavior of Gases

Measuring Gases When working with gases it is helpful to know its volume, temperature and pressure Volume The volume of the gas is the same as the volume of its container. Temperature is a measure of the average energy of motion of the particles of matter. Pressure of the gas is the force of its outward push divided by the area of the walls of the container. Unit for pressure is Pascal (Pa).

Temperature and Volume When the air inside a balloon cools, its volume decreases. When the air inside a balloon warms up its volume increases. Charles’s Law states that when the temperature of a gas increases at constant pressure, its volume increases. When the temperature of a gas decreased at constant pressure, its volume decreases. The graph of Charles’s law will show that the volume of a gas is directly proportional to its temperature under constant pressure.

Pressure and Volume Boyle’s Law states that when the pressure of a gas at constant temperature is increased, the volume of the gas decreases. When the pressure is decreased, the volume increases. The graph for Boyle’s law shows that gas pressure is inversely proportional to volume at constant temperature.

Pressure and Temperature Increasing Temperature Raises Pressure When temperature of a gas at constant volume is increased, the pressure of the gas increases. When the temperature is decreased, the pressure of the gas decreases.