Notes #1: Gases WCHS Chemistry

KINETIC MOLECULAR THEORY “Molecules Move” Theory - a gas consists of small particles that are in constant random motion. Most of a gas is empty space This allows us to change the volume!

KINETIC MOLECULAR THEORY The speed of a gas particle is proportional to its temperature… Higher temp = FASTER movement = LARGER volume = gas EXPANDS Lower temp = SLOWER movement = SMALLER volume = gas CONTRACTS

QUICK NOTE Explosion & Implosion → aggressive & fast vs. Expansion & Contraction→slow & controlled

SIMULATION https://phet.colorado.edu/en/simulation/legacy/gas-properties

Pressure = force per unit area Atmospheric Pressure = pressure exerted by the force of the air above 14.7 lbs of pressure per square inch! About the same as having a small car pressing down on you!

In an Airplane Under water

Pressure can be increased by: Increasing the number of molecules Blowing up a balloon Increasing the temperature Decreasing the volume Gases ALWAYS go from HIGH pressure → LOW pressure!

CLOSED SYSTEM vs. OPEN SYSTEM Closed System - an isolated system that CANNOT interact with an outside environment Open System - a system that CAN interact with an outside environment

EXPLOSION vs. IMPLOSION Explosion - outward movement Due to high pressure in a closed system Implosion - inward movement Due to low pressure in a closed system L H L H