Agenda

• Ideal Gas Law• Gas Laws Review• Gas Laws Practice

Gas Variables

žFour variables to describe a gas:

Pressure (P)Volume (V)Temperature (T)Amount (n)

Ideal Gas Law

žFour variables to describe a gas:

Pressure (P)Volume (V)Temperature (T)Amount (n)

Ideal Gas Law

PV = nRT

P = PressureV = Volumen = Number of MolesR = Gas Constant (Always Provided!)T = Temperature

Ideal Gas Law Relationships

PV = nRTAs Pressure Increases, Temperature Increases

By extension – As Pressure Decreases Temperature Decreases

As Volume Increases, Temperature AND Pressure DecreaseBy extension – As Volume Decreases, Temperature and Pressure Increase

As Amount (number of moles) Increases, Pressure and Temperature Increase

By extension – As Amount Decreases, Pressure and Temperature Decrease

The initial temperature of a 1.0 L sample of argon is 20.° C. The pressure is decreased from 720 mm Hg to 360 mm Hg and the volume increases to 2.14 L. What was the change in temperature of the argon? PV = nRTR = 62.36 L mmHg K−1   mol−1

Kinetic Molecular Theory

Postulates1. Gases consist of tiny particles.2. These particles are so small, compared with the distances between them, that the volume (size) of the individual particles can be assumed to be negligible (zero).3. The particles are in constant random motion, colliding with the walls of the container. These collisions with the walls cause the pressure exerted by the gas.4. The particles are assumed not to attract or to repel each other.5. The average kinetic energy of the gas particles is directly proportional to the temperature of the gas.

Handouts

• Gassy Relationships Handout• Gas Laws Handout• First 3 Gas Laws Worksheet• Gas Relationships Review

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