D

d block Dalton's law
decay constant degenerate orbital
degree of ionization deionized water
deliquescent delocalized molecular orbital
denaturation density
deoxyribonucleic acid deposition
deuterium dextrorotatory
diagonal relationship dialysis
diamagnetic diastereomer
diatomic differential rate equation
differentiating solvent diffusion
dilution dimensional analysis
dimer dipolar force
dipole dipole moment
diprotic disintegration
dispersion force disproportionation
dissociation distillation
DNA double bond
dry ice ductile
dynamic equilibrium  




d block

Columns 3 through 12 of the periodic table, containing elements in which the d atomic orbitals are being filled.


Dalton's law

The statement that the total pressure of a mixture of gases is equal to the sum of the partial pressures of the component gases.


decay constant

A rate constant for radioactive decay or other first-order decomposition reaction.


degenerate orbital

One of two or more orbitals having the same energy.


degree of ionization

The extent to which species in solution ionize. Often applied to the dissociation reactions of acids and bases.


deionized water

Water that has been passed through ion exchange resin to remove impurities that are ionic.


deliquescent

Absorbing moisture from the air so readily as to dissolve in the absorbed water to form a solution.


delocalized molecular orbital

A molecular orbital that encompasses more than two atoms.


denaturation

Chemical or physical forces acting upon a protein so as to disrupt its secondary and tertiary structure. The biological activity of the protein is lost.


density

The ratio of the mass of a material to its volume.


deoxyribonucleic acid

The macromolecules that constitute the genetic material of chromosomes; abbreviated DNA.


deposition

The process of forming a solid from a gas.


deuterium

The isotope of hydrogen having one neutron in its nucleus.


dextrorotatory

Descriptive of a substance that rotates the plane of polarized light to the right.


diagonal relationship

Similarities in chemical or physical properties found between one element (or its compounds) and another element and found in the periodic table either above and to the left or below and to the right of the first element.


dialysis

A process in which ions or small molecules in a solution pass through a semipermeable membrane while larger molecules remain behind.


diamagnetic

Describing a substance containing no unpaired electrons that is repelled by a magnetic field.


diastereomer

One of two or more compounds that have the same chemical composition and that have the same atoms joined to each other, but that are not mirror images of each other.


diatomic

Containing two atoms per molecule.


differential rate equation

An equation that describes the rate of a reaction as a function of the concentrations of reactants (and products), also called rate law.


differentiating solvent

A solvent that is a sufficiently weak base or acid that the acid or base strength of a pair of substances may differentiated in that solvent.


diffusion

The spreading of a material into another (usually a gas or liquid).


dilution

The addition of solvent to a solution (or mixture) to decrease the concentration of a solute (or component).


dimensional analysis

A technique in which the cancelling of units is used as a tool to check the correctness of a calculation.


dimer

A molecule formed by the combination of two smaller identical units.


dipolar force

The attraction between polar molecules as a result of the partially positively charged portion of one molecule being oriented toward the partially negatively charged portion of another molecule.


dipole

An overall electrically neutral species having separated, equal positive and negative charges; such a species tends to assume certain orientations more than others in an electric field.


dipole moment

The separation of electrical charge in a molecule that makes the molecule polar.


diprotic

Describing an acid which can donate two hydrogen ions ("protons") to a base.


disintegration

The event of a nuclear transformation caused by radioactive decay or nuclear bombardment.


dispersion force

Intermolecular forces arising from an instantaneous dipole in one molecule inducing a dipole in another molecule.


disproportionation

A reaction in which a substance undergoes both oxidation and reduction.


dissociation

The breaking apart of one species into two or more smaller species; often applied to an acid as it forms hydrogen ion and its conjugate base and to the ionization of an electrolyte.


distillation

A technique for separating the components of a liquid by vaporizing a portion of the liquid and condensing its vapor.


DNA

Abbreviation for deoxyribonucleic acid; the macromolecules that constitute the genetic material of chromosomes.


double bond

The sharing of two pairs of electrons between bonded atoms to form a strong linkage between the atoms.


dry ice

Frozen carbon dioxide; called dry because of its tendency to sublime (form a gas without first forming a liquid).


ductile

Able to be drawn into a wire.


dynamic equilibrium

A self-establishing state reached when opposing reactions occur at the same rate - any change moving the system from equilibrium will be opposed, and the system will return to equilibrium if possible.



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