Chemistry Dictionary Terminology "O"

Chemistry Dictionary

Terminology "O"

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Octahedral

A term used to describe molecules and polyatomic ions that have one atom in the center and six atoms at the corners of a octahedron.

Octane Number

A number that indicates how smoothly a gasoline burns.

Octet Rule

Many representative elements attain at least a share of eight electrons in their valence shells when they form molecular or ionic compounds; there are some limitations.

Oil

Liquid triester of glycerol and unsaturated fatty acids.

Open Sextet

Refers to species that have only six electrons in the highest energy level of the central element (many Lewis acids).

Optical Activity

The rotation of plane polarized light by one of a pair of optical isomers.

Optical Isomers

Stereoisomers that differ only by being nonsuperimposable mirror images of each other, like right and left hands, also called enantiomers.

Ore

A natural deposit containing a mineral of an element to be extracted.

Organic Chemistry

The chemistry of substances that contain carbon-hydrogen bonds.

Osmosis

The process by which solvent molecules pass through a semipermable membrane from a dilute solution into a more concentrated solution.

Osmotic Pressure

The hydrostatic pressure produced on the surface of a semipermable membrane by osmosis.

Ostwald Process

A process for the industrial production of nitrogen oxide and nitric acid from ammonia and oxygen.

Outer Orbital Complex

Valence bond designation for a complex in which the metal ion utilizes d orbitals in the outermost (occupied) shell in hybridization.

Overlap

The interaction of orbitals on different atoms in the same region of space.

Oxidation

An algebraic increase in the oxidation number; may correspond to a loss of electrons.

Oxidation Numbers

Arbitrary numbers that can be used as mechanical aids in writing formulas and balancing equations; for single- atom ions they correspond to the charge on the ion; more electronegative atoms are assigned negative oxidation numbers (also called Oxidation states).

Oxidation-reduction Reactions

Reactions in which oxidation and reduction occur; also called redox reactions.

Oxide

A binary compound of oxygen.

Oxidizing Agent

The substance that oxidizes another substance and is reduced.