Chapter 3 part 2 THE GAS LAWS Pressure

Chapter 3 part 2 THE GAS LAWS

Pressure �The result of a force distributed over an area �Unit for pressure is : �Pascal = N/m 2 �Usually expressed in k. Pa – kilopascals

Pressure �Formula for Pressure: �Pressure = Force ÷ Area �Example: 100 newtons of force is exerted over an area of 5 m 2. How much pressure exists?

Factors that affect gas pressure �Factors that affect the pressure of an enclosed gas are . . . �Temperature �Volume �Number of particles

Temperature �Raising the temperature INCREASES the pressure IF. . . �The volume and # of particles are constant

Volume �Reducing the volume INCREASES the pressure IF. . . �The temperature and the # of particles remains constant

Charles’s Law �Relates Volume and Temperature �The volume of a gas is directly proportional to its temperature (pressure held constant) �Formula:

Boyle’s Law �Relates PRESSURE and VOLUME �Temperature is held constant �Inverse Relationship �Formula:

Combined Gas Law �Describes the relationship among the temperature, volume, and pressure of a gas �# of particles is held constant �Formula:

Practice Problems �A gas has a volume of 5. 0 L at a pressure of 50 k. Pa. What happens to the volume when the pressure is increased to 125 k. Pa? Temp is held constant? �Gas stored in a tank at 273 K has a pressure of 388 k. Pa. The safe limit for the pressure is 825 k. Pa. At what temp will the gas reach this pressure?