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Pure Substance Definition

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					Pure Substance definition is that, it is a material that
is homogeneous or has constant composition.

Throughout the sample, a pure substance or chemical
substance has constant properties. Chemical
elements and chemical compounds are pure
substances.

All elements are pure substance. Examples of
chemical elements that are pure substances are tin,
sulphur, and diamond.
Chemical compounds on the other hand that are pure
substances include water, salt, sugar, gold, and
baking soda. Example, for pure water, it has the
same properties and the same ratio of hydrogen to
oxygen.
Pure water is composed of 2 hydrogen atoms and 1
oxygen atom which are bonded chemically. Pure
water us an example of pure substance definition
because distilling it will not separate water into its
components which are hydrogen and oxygen. Instead,
it will only produce water vapor. For pure gold on the
other hand is composed only of 1 pure gold atom.
Pure substance definition is explained more by theses
example.
The chemical or pure substance definition is clear, all
elements are pure substances. This is because they have
no impurities and are not combined yet to other elements
or compounds.

A compound on the other hand is a combination of 2 or
more elements. But even if it is a combination of elements,
this combination of elements or compounds can no longer
be separated into 2 or more substances.

Another example of a compound pure substance is a salt.
Salt is a mixture Sodium and Chlorine. Even through
sifting, decantation, visual sorting, magnetic attraction,
separating funnel, filtration, evaporation, crystallization,
distillation, or other physical and mechanical ways are
applied to the salt, the 2 elements cannot be separated.
   Scientists have found out that there were certain basic
    substances found in all materials. These substances
    which are also referred as “building blocks of matter”
    are called elements. All of these are pure substances
    which cannot be broken down to simpler substances.
    Compounds, as explained above, are substances that
    are made by combination of 2 or more elements.

   Other pure substance definition is a sample of matter,
    whether an element or compound, which composed of
    one component. The element or compound should have
    definite chemical and physical properties and
    composition. A pure substance cannot be separated into
    2 or more substances by mechanical or physical method
    like filtering, crystallization, sifting, distillation, and
    other means.
Additional pure substance definition is that its properties
do not rely on how it is purified or prepared. It has
constant chemical composition and the properties are
always constant. But, there is also exemption to this pure
substance definition. There is pure substance that can be
defined as a form of matter that has both distinct
properties and definite composition. There are several
alloys that have uncertain composition.

Chemical or pure substance displays sharp boiling and
melting point. Based on the pure substance definition, it
also has constant density, color, and appearance
throughout the sample. But for some, homogenous
mixtures like vegetable oil, air, and honey are also
considered based on pure substance definition.

http://puresubstance.org/pure-substance-definition-
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posted:4/27/2012
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