Unit 9 part 1: States of Matter Lecture Notes

A set of vocabulary flashcards based on lecture notes covering the kinetic theory of gases, pressure units, properties of liquids and solids, and changes of state.

Kinetic Theory

A theory that deals with the movement of particles (atoms, molecules), stating that gas particles are small, far apart, and in constant, random motion.

Random walk

The rapid, chaotic, random, and constant motion of gas particles for a given temperature.

Perfectly elastic

A characteristic of gas particle collisions with objects or other particles where no energy is lost.

Gas Pressure

The force exerted when gas particles collide with another object; billions of molecules are required for measurable force.

Vacuum

A condition containing no particles and no collisions.

Atmospheric pressure

Pressure resulting from the collisions of air molecules with an object, which is measured with a barometer and decreases at higher elevations like Mt. Everest.

Pascal (Pa)

The SI unit of pressure.

Standard Pressure Equivalents

$$1\,atm = 101.3\,kPa = 14.7\,psi = 760\,mmHg\text{ (torr)} = 1013\,mb$$

Average Kinetic Energy

A measure of the motion of particles in a substance; temperature is defined as the measure of this average energy.

Absolute zero

The temperature at which all motion of particles stops, defined as $0\,K$ or $-273^{\circ}C$.

Evaporation

A form of vaporization where a liquid turns into a gas at the surface, which is a cooling process because high-energy particles are removed.

Vapor Pressure

The force exerted by a gas above a liquid, which increases as temperature increases and can be measured with a manometer.

Boiling Point

The temperature at which the vapor pressure of a liquid is equal to the external air pressure.

Normal B.P.

The boiling point of a substance at $1\,atm$ of pressure.

Crystalline

A solid that possesses an orderly arrangement of particles.

Melting point

The temperature at which a solid turns to a liquid as particles gain enough kinetic energy to break attractive forces.

Allotropes

Solids that exist in more than one form; example Carbon allotropes include diamond, graphite, and buckminsterfullerene.

Amorphous

Solids that have no ordered arrangement and no definite melting point, such as rubber, plastic, and glass.

Sublimation

The direct change of state from solid ($S$) to gas ($G$).

Deposition

The direct change of state from gas ($G$) to solid ($S$).

Triple point

The point on a phase diagram at which all three states of matter exist at once.