Mixtures of Matter

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Mixtures of Matter

• Most stuff is a mixture!
• Section 3.3

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Mixtures

• Combo of 2 or more pure substances.
• Physically combined but chemically combined.
• Each substance retains its own identity and
  properties.

not
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Mixtures

• Variable composition
• No unique properties. (Think of sugar and salt
  mixed together.)
• Separated by physical methods.
• May be homogeneous or heterogeneous.

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Types of Mixtures

1. Heterogeneous

• See a boundary or regions that look
  different.
• ice water, granite, pepper

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Types of Mixtures

• Constant composition throughout, single phase.
• Solutions (all 3 phases), air, windex, kool-aid,
  sterling silver

1. Homogeneous

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Homogeneous Mixtures
Gas / Gas Gas / Liquid Gas / Solid Liquid /
Gas Liquid / Liquid Liquid / Solid Solid /
Gas Solid / Liquid Solid / Solid
Air Soda Water H2 in Pt Water in Air Alcohol in
Water Mercury in Silver Mothballs in Air Salt in
Water Silver in Gold
SOLUTIONS
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Hints for Mixtures

• Solutions in the gas liquid phases transmit
  light. (No particles big enough to scatter
  light.) They look translucent.

Homogeneous
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Hints for Mixtures

• Suspensions look cloudy the particles are big
  enough to scatter light. They settle on
  standing. If it has to be shaken or stirred,
  its a heterogeneous mixture!

Heterogeneous
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CuSO4(aq)
source
source
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Hints for Mixtures

• Any formula with (aq) is a solution or a
  homogeneous mixture.
• If 1 substance is dissolved in another, its a
  solution or a homogeneous mixture.

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Hints for Mixtures

• Which of the following is a mixture?
• NaCl(s)
• CH3OH(l)
• HF(g)
• KCl(aq)

Means KCl H2O
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Hints for Mixtures

• Potassium iodide dissolved in water is an example
  of
• A) element
• B) compound
• C) homogeneous mixture
• D) heterogeneous mixture

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Separating Mixtures

• Physically combined.
• Separation based on physical properties.
• Sorting Appearance
• Filtration Size
• Distillation Boiling Point
• Crystallization Solubility
• Magnet Magnetization
• Chromatography Travel ability

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Use differences in appearance to sort the coins.
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Filtration based on differences in particle size.
Larger particles are trapped by filter.
source
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Distillation
Based on differences in boiling point.
source
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source
Paper Chromatograhy
source
Based on differences in intermolecular forces.
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Crystallization
Source
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Crystallization
source
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Magnetic Properties

• Magnetic properties can be used to separate
  mixtures.
• Sand iron filings can be separated with a
  magnet.