Dalton’s Law of Partial Pressures

The total pressure of a mixture of gases is just the sum of the pressures that each gas would exert if it were present alone.

Decomposition Reaction

The breakdown of a compound into two or more components.

Degenerate Orbitals

Orbitals that have the same energy.

Delocalized Molecular Orbitals

Molecular orbitals that are not confined between two adjacent bonding atoms but actually extend over three or more atoms.

Denatured Protein

Protein that does not exhibit normal biological activities.

Density

The mass of a substance divided by its volume.

Deoxyribonucleic Acids

A type of nucleic acid.

Deposition

The process in which the molecules go directly from the vapor into the solid phase.

Diagonal Relationship

Similarities between pairs of elements in different groups and periods of the periodic table.

Diamagnetic

Repelled by a magnet; a diamagnetic substance contains only paired electrons.

Diatomic Molecule

A molecule that consists of two atoms.

Differential

An equation used to describe electron motion by the wave equation.

Diffusion

The gradual mixing of molecules of one gas with the molecules of another by virtue of their kinetic properties.

Dilute

A procedure for preparing a less concentrated solution from a more concentrated solution.

Dilution

A less concentrated solution prepared from a more concentrated solution.

Dipole Moment

The product of charge and the distance between the charges in a molecule.

Dipole-Dipole Forces

Forces that act between polar molecules.

Diprotic Acid

Each unit of the acid yields two hydrogen ions upon ionization.

Disaccharide

An organic compound formed by a dehydration-condensation reaction between two simple sugars (monosaccharides).

Dispersion Forces

The attractive forces that arise as a result of temporary dipoles induced in the atoms or molecules; also called London forces.

Displacement Reaction

An atom or an ion in a compound is replaced by an atom of another element.

Disproportionation Reaction

A reaction in which an element in one oxidation state is both oxidized and reduced.

Donor Atom

The atom in a ligand that is bonded directly to the metal atom.

Donor Impurities

Impurities that provide conduction electrons to semiconductors.

Double Bond

Two atoms are held together by two pairs of electrons.

Dynamic Equilibrium

The condition in which the rate of a forward process is exactly balanced by the rate of a reverse process.