Chapter 12-14

Solid

State of matter with a fixed shape and volume.

Liquid

State of matter with a definite volume but no fixed shape.

Gas

State of matter with no fixed shape or volume.

Molar Mass

Mass of one mole of a substance (g/mol).

Molar Volume

Volume occupied by one mole of a substance (L/mol).

Crystalline Solids

Solids with a highly ordered, repeating arrangement of atoms/molecules.

Amorphous Solids

Solids with no long-range order or repeating structure.

Vapor Pressure

The pressure exerted by a vapor in equilibrium with its liquid.

Dispersion Forces

Weak intermolecular forces increasing with molecule size.

Like Dissolves Like

Polar solvents dissolve polar substances; nonpolar solvents dissolve nonpolar substances.

Adhesion

Attraction between molecules of different substances.

Cohesion

Attraction between molecules of the same substance.

Surface Tension

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

Capillary Effect

The ability of a liquid to flow against gravity in a narrow space.

Viscosity

A liquid’s resistance to flow.

Meniscus

The curve of a liquid’s surface in a container.

Condensation

Gas to liquid phase change.

Heat of Phase Change

Energy required for a substance to change phase.

Dynamic Equilibrium

A state where the rates of forward and reverse processes are equal.

Heating Curve

Graph showing temperature vs. heat added.

Crystal Lattice

3D arrangement of atoms or molecules in a crystalline solid.

Unit Cell

The smallest repeating unit in a crystal lattice.

Coordination Number

Number of nearest neighbors around an atom in a crystal.

Packing Efficiency

Percentage of space occupied in a crystal lattice.

Simple Cubic (SC)

1 atom/unit cell, 52% packing efficiency.

Body-Centered Cubic (BCC)

2 atoms/unit cell, 68% packing efficiency.

Face-Centered Cubic (FCC)

4 atoms/unit cell, 74% packing efficiency.

Polymorphs

Different crystal structures of the same substance.

Metallic Bonding

Positive metal ions surrounded by a 'sea of electrons.'

Band Theory

Explains electrical conductivity based on valence and conduction bands.

Conductor

Freely moving electrons (e.g., metals).

Semiconductor

Conductivity increases with temperature.

Insulator

No free electrons (e.g., rubber).