Mixtures

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Mixtures

• Mr. V. Perez
• Grade 6 Science

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Mixtures

• A mixture is a material made up of two or more
  substances that have been combined physically,
  but not chemically
• The substances keep their own properties and can
  normally be separated
• The substances have no definite chemical
  composition
• What items can you see on the pizza?

• Cheese, peppers, sausage, sauce, green peppers,
  red peppers, onions, mushrooms, and meatballs

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Heterogeneous Mixtures

• Some of the items on pizza could be easy to see
  like the peppers, sausage, cheese, or sauce
• Some items, like the cheese, can be a mixture
  that cannot be seen
• Cheese is made from many compounds such as milk,
  proteins, butterfat, colorings, and additives.
  These substances went through a chemical change
  when they formed the cheese (before the cheese
  was even put on the pizza).
• Heterogeneous Mixtures are mixtures in which
  different materials can easily be distinguished
  (most of the time)
• Heterogeneous Mixtures have more than one color
• Ex trail mix, a mixed salad / tossed salad,
  pizza, dirt, salad dressings, granite, concrete,
  sand and water, etc.

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Heterogeneous Mixtures

• You might be wearing a heterogeneous mixture,
  such as a shirt made out of different fibers

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Homogeneous Mixtures

• Homogeneous Mixtures contain two or more gaseous,
  liquid, or solid substances blended evenly
  throughout
• Homogeneous Mixtures appear one color
• Vinegar is a homogeneous mixture because it is
  made up of particles of acetic acid mixed with
  water (and is a clear liquid)
• Ex milk, juice, salt, sugar, lemon juice
  (without pulp), sugar and water, salt and water,
  water and food coloring (dye), etc.
• Flat soda is a homogeneous mixture (because the
  carbon dioxide has been released from the soda)
• Another name for a homogeneous mixture (like
  vinegar or flat soda) is a solution

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Is Soda Heterogeneous or Homogeneous?
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Ways to Separate a Mixture

• Filtration separates bigger particles from
  smaller particles (by using filter paper,
  strainers, and screens that are different sizes).
  The spaces between the parts of the strainer or
  filter can vary in size depending on the amount
  of material that you want to pass through it.
  The larger the holes, the more material that
  passes.
• Evaporation is when some particles stay behind in
  a beaker after the water changes from a liquid to
  a gas
• Distillation is a process that can separate two
  substances in a liquid while recondensing AND
  collecting its vapor. This is how you get pure
  water.
• Magnetism can separate iron from other substances
  by using a magnet. Iron, nickel, and cobalt have
  magnetic properties and are attracted to a magnet.

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Filtration (Strainer)
A strainer, or screen, is used to separate the
seeds (large particles) from the sand (small,
fine particles). The holes in the screen are
small enough to let the tiny particles of sand
through.
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Filtration(Filter Paper)
Filter paper and a funnel can be used to separate
solid particles (that do not dissolve in the
liquid) from the liquid. The larger solid
particles get caught in the filter paper. The
liquid will be separated and end up in the beaker
on the bottom.
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Distillation

• The mixture, or impure liquid, is heated (in the
  distilling flask)
• The liquid water evaporates from the heat and
  rises as water vapor
• The water vapor condenses as it contacts the cool
  water in the condenser
• Pure liquid water is collected in the flask to
  the right
• The impure substance (debris) will remain in the
  distilling flask

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Magnetism
You can use a magnet to separate the iron filings
from the sand. The iron filings have the chemical
property of magnetism, so they are attracted to
the magnet. The sand is not attracted to the
magnet, so it will remain in the dish (and not on
the magnet).
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Mixtures Review
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Distillation Sheet - Answer Key

• The water and impurities are heated
• The water is boiling at 100º C
• Evaporation (liquid to gas). The flame is the
  energy source.
• The water vapor is cooled in the condenser. The
  water vapor travels to the flask with ice.
• Condensation (gas to liquid). Cooling the water
  vapor with ice.
• Evaporation (liquid to gas) and Condensation (gas
  to liquid).
• You get pure water by separating the water from
  the impurities.