http://www.ck12.org Chapter 27. Glossary
27.4 D
Dalton’s law of partial pressures
A law that states that the total pressure of a mixture of gases is equal to the sum of all of the partial pressures
of the component gases.
decay series
A sequence of successive radioactive decays that proceeds until a stable nuclide is reached.
decomposition reaction
A reaction in which a compound breaks down into two or more simpler substances.
delocalized electrons
Electrons that are not confined to the bond between two atoms but are, instead, allowed to move between three
or more.
density
The ratio of the mass of an object to its volume.
dependent variable
The experimental variable that is observed during an experiment.
deposition
The change of state from a gas to a solid.
derived unit
The unit that results from a mathematical combination of SI base units.
diatomic element
An element whose natural form is of a diatomic molecule.
diatomic molecule
A molecule containing two atoms.
diffusion
The tendency of molecules to move from an area of high concentration to an area of low concentration until
the concentration is uniform.
dilute
A solution that has a relatively small amount of dissolved solute.
dimensional analysis
A technique that uses the units (dimensions) of the measurement in order to correctly solve numerical prob-
lems.
dipole
A molecule with two poles, a positive pole and a negative pole; also called a polar molecule.
dipole-dipole forces
The attractive forces that occur between polar molecules; the positive end of one dipole is attracted to the
negative end of a neighboring dipole.
disaccharide
A carbohydrate formed by the joining of two monosaccharides.
dissociation
The separation of ions that occurs when a solid ionic compound dissolves.
distillation
Method of separating a mixture based on differences in boiling points.
double covalent bond
A covalent bond formed by atoms that share two pairs of electrons.
double-replacement reaction
A reaction in which the positive and negative ions of two ionic compounds exchange places to form two new