What do the term homogeneous and heterogeneous mean?

Question

What do the term homogeneous and heterogeneous mean?

Answer 1

A homogeneous substance is that which has uniform composition and other properties at all its locations. Thus, all the samples from different locations of that substance will show uniform properties. Theoretically, there is no substance which is really homogeneous since local variations do exist on atomic and molecular scale. However, most of the 'pure' substances are considered as homogeneous for all practical purposes.

Thus a glass of water, the air in a closed room (at equilibrium and without heat sources) are examples of homogeneous substances.

It is easier to identify inhomogeneous mixtures (heterogeneous) and compounds than to certify a substance as homogeneous. The finer our tools, the more inhomogeneous we will find it. Also, the smaller the sample size, the more will be the variation from sample to sample.

Answer 2

Homogenous - of a single consistency or character. Often considered to be an indication of purity.  Water, pure gold, air, and glass come to mind.

Heterogenous - Having more than one consistency or character.  Oil and vinegar dressing comes to mind.

Answer 3

homogeneous means of the same or a similar kind or nature

Heterogeneous is an adjective used to describe a thing that has a large number of variants or different shape and structure.

heterogeneous reactionchemical reaction

Main

any of a class of chemical reactions in which the reactants are components of two or more phases (solid and gas, solid and liquid, two immiscible liquids) or in which one or more reactants undergo chemical change at an interface, e.g., on the surface of a solid catalyst. The reaction of metals with acids, the electrochemical changes that occur in batteries and electrolytic cells, and the phenomena of corrosion are part of the subject of heterogeneous reactions. By far the majority of the researches on heterogeneous reactions are devoted to heterogeneous catalysis (e.g., the reactions between gases or liquids accelerated by solids). Heterogeneous reactions are of considerable practical interest; they are not, however, understood as well as those reactions that occur in only one phase (homogeneous reactions).

Now homogeneous: are

any of a class of chemical reactions that occur in a single phase (gaseous, liquid, or solid), one of two broad classes of reactions—homogeneous and heterogeneous—based on the physical state of the substances present. The most important of homogeneous reactions are the reactions between gases (e.g., the combination of common household gas and oxygen to produce a flame) and the reactions between liquids or substances dissolved in liquids (e.g., the reactions between aqueous solutions of acids and bases). From the theoretical standpoint, homogeneous reactions are the simpler of the two classes of reactions because the chemical changes that take place are solely dependent on the nature of the interactions of the reacting substances

Answer 4

homogeneous; in chemistry, involving substances in the same phase (solid, liquid, or gas)

heterogeneous; of a mixture) composed of different substances or the same substance in different phases, as solid ice and liquid water.

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