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A measure of the amount of matter in an object. Mass is usually measured in grams or kilograms.

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Net Ionic Equation

Equation that results from canceling spectator ions and eliminating brackets from a total ionic equation.

Acid Anhydride

Compound produced by dehydration of a carbonic acid. General formula is R--C--O--C--R. Chemical compound that reacts with water to form an acid and are usually oxides of nonmetallic elements.

Mole Fraction

The number of moles of a component of a mixture divided by the total number of moles in the mixture.



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


Having the same electronic configurations.

Capillary Action

The drawing of a liquid up the inside of a small-bore tube when adhesive forces exceed cohesive forces, or the depression of the surface of the liquid when cohesive forces exceed the adhesive forces.

xenon hexafluoride

A colorless, crystalline compound, XeF6, that melts at 50°C to a yellow liquid, and boils at 75°C.

Effective Nuclear Charge

The nuclear charge experienced by the outermost electrons of an atom, the actual nuclear charge minus the effects of shielding due to inner-shell electrons.
Example: Set of dx2-y2 and dz2 orbitals, those d orbitals within a set with lobes directed along the x-, y-, and z-axes.

Evaporation Rate

The rate at which a particular substance will vapourize (evaporate) when compared to the rate of a known substance such as ethyl ether. This term is especially useful for health and fire-hazard considerations.

Kinetic-molecular Theory

A theory, that attempts to explain macroscopic observations on gases in microscopic observations on gases in microscopic observations on gases in microscopic or molecular terms.