Mixtures

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Mixtures
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Mixtures

• A mixture is a form of matter that is composed of
  two or more elements, two or more compounds, or
  of elements and compounds.

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Mixtures

• In a mixture, the individual components USUALLY
  retain their own individual properties.
• In air, nitrogen, oxygen, argon, and other gases
  all retain their own individual properties.

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Mixtures

• The components of a mixture are physically
  combined and need NOT be composed in a definite
  (unique) ratio.

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Mixtures

• A mixture is not a substance because all samples
  are not necessarily alike in composition.

Does the salt and water mixture on the left
have to be made in the same ratio as the one on
the right?
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Mixtures

• A mixture can be either homogeneous or
  heterogeneous.
• A homogeneous mixture is one in which all of the
  components are UNIFORMILY distributed.
• A heterogeneous mixture is one in which the
  components are NOT UNIFORMILY distributed.

HOMOGENEOUS
HETEROGENEOUS
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Mixtures

• Solutions are the ONLY type of homogeneous
  mixtures!
• All mixtures of two or more different gases are
  homogeneous and thus solutions.

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Mixtures

• Filtering cannot separate a solution because the
  components are too small.

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Mixtures

• A solution will not separate if left standing.

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Mixtures

• A beam of light will not be diffracted when
  passed through a liquid or gaseous solution and
  thus will remain unseen.

a solution
not a solution
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Mixtures

• Alloys are also solutions because they are a
  homogeneous mixture of two or more metals!
• ALLOYS ARE NOT COMPOUNDS BECAUSE THE ELEMENTS DO
  NOT HAVE TO BE IN A UNIQUE RATIO!
• Brass, bronze, and steel are examples of alloys.

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Mixtures

• All other types of mixture are heterogeneous
  because the components are not uniformly (evenly)
  distributed.
• Suspensions and colloids are two examples of
  heterogeneous mixtures.

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Mixtures

• A suspension is a heterogeneous mixture in which
  some of the component particles are large enough
  to be seen by the naked eye and which will
  separate when left standing.

Suspension before settling.
Suspension after settling.
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Mixtures

• A colloid is a heterogeneous mixture in which the
  components are microscopic (the particles cant
  be seen by the eye) and will not separate when
  left standing.

In this colloidal silver mixture, the particles
of silver are too small to be seen with the
naked eye.
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Mixtures

• A colloid can be distinguished from a solution by
  shining a light beam through the sample. If the
  light can be seen, then the same is a colloid.

a solution
a colloid
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Mixtures

• Ex. (1) A mixture of nitrogen gas, oxygen gas,
  and argon gas is classified as
• (1) an element
• (2) a compound
• (3) a homogeneous mixture
• (4) a heterogeneous mixture
• Ex. (2) The alloy bronze is composed of copper
  and tin. Bronze is classified as
• (1) an element
• (2) a compound
• (3) a homogeneous mixture
• (4) a heterogeneous mixture

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Mixtures

• Ex. (3) Brine is a solution of salt and water.
  Brine is classified as
• (1) an element
• (2) a compound
• (3) a homogeneous mixture
• (4) a heterogeneous mixture
• Ex. (4) Which class of matter cannot be separated
  by either a physical method or a chemical
  method?
• (1) an element
• (2) a compound
• (3) a homogeneous mixture
• (4) a heterogeneous mixture

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Mixtures

• Ex. (5) Which class of matter can be separated by
  a chemical method but not by a physical
  method?
• (1) an element
• (2) a compound
• (3) a homogeneous mixture
• (4) a heterogeneous mixture
• Ex. (6) In which class of matter can the
  components usually be separated by filtering?
• (1) an element
• (2) a compound
• (3) a homogeneous mixture
• (4) a heterogeneous mixture

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Mixtures