Termolecular Reaction

An elementary step that involves three molecules.

Ternary Compounds

Compounds consisting of three elements.

Theoretical Yield

The amount of product predicted by the balanced equation when all of the limiting reagent has reacted.

Theory

A unifying principle that explains a body of facts and the laws that are based on them.

Thermal Energy

Energy associated with the random motion of atoms and molecules.

Thermal Pollution

The heating of the environment to temperatures that are harmful to its living inhabitants.

Thermochemical Equation

An equation that shows both the mass and enthalpy relations.

Thermochemistry

The study of heat changes in chemical reactions.

Thermodynamics

The scientific study of the interconversion of heat and other forms of energy.

Thermonuclear Reactions

Nuclear fusion reactions that occur at very high temperatures.

Thermosphere

The region of the atmosphere in which the temperature increases continuously with altitude.

Third Law of Thermodynamics

The entropy of a perfect crystalline substance is zero at the absolute zero of temperature.

Titration

The gradual addition of a solution of accurately known concentration to another solution of unknown concentration until the chemical reaction between the two solutions is complete.

Tracers

Isotopes, especially radioactive isotopes, that are used to trace the path of the atoms of an element in a chemical or biological process.

Transition Metals

Elements that have incompletely filled d subshells or readily give rise to cations that have incompletely filled d subshells.

Transition State

See activated complex.

Transuranium Elements

Elements with atomic numbers greater than 92.

Triple Bond

Two atoms are held together by three pairs of electrons.

Triple Point

The point at which the vapor, liquid, and solid states of a substance are in equilibrium.

Triprotic Acid

Each unit of the acid yields three protons upon ionization.

Troposphere

The layer of the atmosphere which contains about 80 percent of the total mass of air and practically all of the atmosphere’s water vapor.