1. STAR Review Standard 4 Gases and Their Properties

2. Gas Pressure  Gas molecules inside a volume are constantly moving around freely.  During this molecular motion they frequently collide with each other and with the surface of any enclosure there may be in.

3. Movement of Gases

4. STP  Standard Temperature and Pressure Equivalent STP values Standard TemperatureStandard Pressure 0oC0oC 1 atm 273.15 K (SI units)101,325 Pa (SI units) 32 o F101.325 kPa (SI units) 760 mm Hg 14.7 lb/in 2 1 bar

5. Absolute Zero  Absolute zero is the point where no more heat can be removed from a system,  0 K or -273.15°C  In classical kinetic theory, there should be no movement of individual molecules

6. One of the first instruments used to measure gas pressure was designed by the Italian scientist Evangelista Torricelli (1608-1647). He invented the barometer, an instrument that measures the pressure exerted by the atmosphere.

7. Boyle’s Law  P1V1=P2V2  As pressure increases, volume decreases

8. Charles’s Law

9. Gay-Lussac’s Law

10. Combined Gas Law

11. Ideal Gas Law  PV = nRT  P= pressure (atm)  V= volume (Liters)  N= # of moles  R= constant (0.821 L. atm/mol. K)  T= temperature (Kelvin)