Phase Changes and Heat Transfer - Video Notes

Vocabulary flashcards covering phase changes, heating curves, and related heat calculations from the lecture notes.

Phase change

A transition between solid, liquid, or gas states that occurs with heat transfer and typically happens at a specific temperature and during which heat is absorbed or released without a rise in temperature.

Isothermal

A process in which the temperature remains constant.

Latent heat

Heat absorbed or released by a substance during a phase change without a change in temperature.

Heat of fusion

The amount of energy required to melt one gram (or one mole) of a solid at its melting point; also called enthalpy of fusion.

Heat of vaporization

The amount of energy required to vaporize one gram of a liquid at its boiling point; enthalpy of vaporization.

Enthalpy

A measure of the total heat content of a system; in these contexts it is the heat energy associated with phase changes.

q = m c ΔT

The formula for heat added or removed when the temperature changes; m is mass, c is specific heat capacity, ΔT is change in temperature.

Specific heat capacity

The amount of heat required to raise the temperature of 1 gram of a substance by 1 degree Celsius (or 1 kelvin).

Heating curve

A graph of temperature versus heat added that shows diagonal rises and plateaus during phase changes.

Plateau

A flat region on the heating curve where a phase change occurs and temperature remains constant.

Melting

Phase change from solid to liquid; requires heat of fusion.

Boiling (vaporization)

Phase change from liquid to gas; occurs at the boiling point; heat of vaporization is absorbed.

Condensation

Phase change from gas to liquid; releases heat; temperature remains constant during the change.

Freezing

Phase change from liquid to solid; releases heat; occurs at the freezing point.

Joule

The SI unit of energy; 1 joule equals 1 newton meter.

Calorie

A unit of energy used in chemistry and food; 1 calorie equals 4.184 joules.