17 Temperature and Kinetic Theory Thermal Equilibrium and Temperature Gas Thermometers and Absolute Temperature The Ideal Gas Law The Kinetic Theory of Gases Hk: 15, 33, 39.

Temperature & Energy temperature: a measurement of the average KE per molecule thermal energy: the kinetic energy resulting from the random movement of atoms and molecules absolute temperature scale: a scale in which the temperature is proportional to the thermal energy. Has true zero.

Thermal Equilibrium thermometric property: A physical property that changes with temperature, e.g. volume. thermal equilibrium: zero net heat flow while in thermal contact 0 th Law 

0 th Law

Celsius Fahrenheit Conversions

Absolute Kelvin Scale

Ideal Gases N molecules (few intermolecular collisions, no long range forces) v = average speed P due to wall-collisions (P ~ Nv/t) t = time between same-wall collision

Ideal gas pressure

Ideal Gas Law

11 Gas Thermometer PV ~ NT P ~ T Gas cools, avg. KE  0, (absolute zero), P  0, ≈ -273 °C

12 Ex. Constant Pressure process on an Ideal Gas What % increase in V occurs for an ideal gas heated from 20C to 40C? (V ~ T) (It does not double, b/c C is not a thermodynamic temperature scale) V2/V1 = T2/T1 = (273+40)/(273+20) = % increase in volume.

Summary Thermal Equilibrium and Zeroth Law Temperature and scales and conversions Thermometric properties and thermometers Ideal Gas Law Kinetic Theory explains gas behavior in terms of Newton’s Laws of Motion. /

The absolute temperature of a gas is most closely associated with its molecules average 1.Velocity 2.Speed 3.(Speed) 2 4.Momentum

What happens to the pressure of an ideal gas going from state A to B? 1.Increases 2.Decreases 3.No change