Catalyst
A substance that accelerates a chemical reaction without itself being a reactant.

Cathode
The positives electrode at which reduction occurs.

Cation
An atom or molecule with a positive charge.

Charles's Law
The volume a gas varies directly with temperature.

Compound
A substance formed by the chemical combination of two or more elements.

Concentration
The relative abundance of a solute in a solution.

Congeners
Elements with similar properties, found in one column of the periodic table.

Conjugate
An acid and base that are related by removing or adding a single hydrogen ion.

Covalent bond
Atoms linked together by sharing valence electrons.

Critical point
A point in a phase diagram where the liquid and gas states cease to be distinct.

Crystalline
The regular, geometric arrangement of atoms in a solid.