Gas Law & Kinetic Theory Summary

Objectives 1. State the P-V relation, the p-T relation, V-T relation and the general gas law for a fixed mass of gas 2. Describe an experiment to verify each gas law (or relations) 3. Apply gas laws to solve problems 4. Express temperatures in the Kelvin scale 5. Describe the physical significance of the absolute zero of temperature 6. Explain gas pressure in terms of the kinetic theory

Kinetic Theory General Gas Law Boyle’s Law PV/T=Constant Pressure Law Charles’ Law New Scale -- Kelvin Temperature Scale

Charles’ Law Boyle’s Law Pressure Law Describe an experiment to verify each gas law (or relations) Charles’ Law V/T=Constant Boyle’s Law Pressure Law P/T=Constant PV=Constant

General Gas Equation PV/T = constant P1V1/ T1 = P2V2/T2 Boyle’s Law: PV = constant Charles’ Law: V/T = constant Pressure Law: P/T = constant PV/T = constant P1V1/ T1 = P2V2/T2

Explain, in terms of the kinetic theory i. why the pressure of a gas increases when it is compressed at constant temperature? ii. why the pressure of a fixed volume of gas increases with temperature? iii. why the volume of a gas increases when heated at constant pressure?

Kinetic theory and Boyle’s Law i. why the pressure of a gas increases when it is compressed at constant temperature? Kinetic theory and Boyle’s Law When a gas is compressed at constant temperature, the molecules have less volume to move and hit the wall of the container more frequently. As a result, pressure will increases.

Kinetic theory and Pressure Law ii. why the pressure of a fixed volume of gas increases with temperature? Kinetic theory and Pressure Law As temperature rises, the molecules move faster, The molecules will hit the walls of the container frequently and violently. Hence, the pressure increases

Kinetic theory and Charles’ Law iii. why the volume of a gas increases when heated at constant pressure? Kinetic theory and Charles’ Law When a gas is heated, the gas molecules move faster and hit the wall of the container violently. The volume of gas must increase to keep the pressure constant. So that the gas molecules hit the wall less frequently.