Chem Unit 2

viscosity

A measure of the resistance of a liquid to flow

surface tension

The energy required to increase the surface area of a liquid by a given amount.

Crystalline Solid

A solid whose atoms, ions, or molecules are arranged in an orderly, geometric, three dimensional structure.

Ionic Solid

Solids that are held together by oppositely charged ions. Example: NaCl

Molecular Solid

Solids that are held together by oppositely charged ions. Example H2O

Amorphous Solid

A solid in which the particles are not arranged in a regular, repeating pattern.

Melting Point of a crystalline solid

the temperature at which the forces holding its crystal lattice together are broken, causing the solid to become a liquid.

Vapor Pressure

The pressure exerted by a vapor over a liquid.

Boiling Point

The temperature at which the vapor pressure of a liquid equals the external or atmospheric pressure.

Freezing Point

The temperature at which a liquid is converted into a crystalline solid.

Triple Point

The point on a phase diagram representing the temperature and pressure at which three phases of a substance can coexist.

Critical Point

The critical pressure and critical temperature above which a substance can not exist as liquid.

Adhesive Forces

Force of attraction between molecules that are different.

Cohesive forces

Forces of attraction between identical molecules.

Diffusion

The movement of one material through another from an area of higher concentration to an area of lower concentration.

Effusion

gas escaping through a tiny opening.