More about Matter

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More about Matter

• Use the information on these slides to check and
  improve your organization of matter.

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Is Air matter?

• What are the two criteria for matter?
• Takes up space
• Has mass

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What is NOT Matter?

• Energy!

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What is the composition of matter?
Matter
Pure Substance
Mixture
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What is a pure substance?

• A pure substance has a definite composition
  (chemical formula).
• The composition of a substance will have the
  same percent of elements no matter where the
  sample was obtained.
• Water from the Cuyahoga River and water from the
  Pacific Ocean (once cleaned up) will have the
  same ratio of hydrogen to oxygen.
• Oxygen here is the same as in Columbus

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What is a pure substance?

• A pure substance, by definition, is an element or
  a compound.
• Water is a compound, and thus a pure substance.

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Pure Substance
Pure Substance
Compound
Element
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What is an element?

• a pure substance made of only one kind of atom
• An atom is the smallest unit of an element that
  maintains the properties of that element.

Element
Atom
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Elemental Samples

• Zinc, copper, lead, carbon, sulfur
• anything on the periodic table

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What is a compound?

• a substance that is made from the atoms of two
  or more elements that are chemically bonded
• has a definite chemical formula
• cannot be broken down any farther by
• simple physical means
• smallest amount of a compound with all the
  properties is a molecule

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What is a compound?

• A molecule is the smallest unit of a compound.

Compound
Molecule
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Examples of compounds?

• Carbon dioxide CO2
• Water H2O
• Sugar C6H12O6
• Oxygen O2
• Table salt NaCl
• 1 molecule of table salt is the smallest amount
  that is still table salt. Cant break it down
  any farther by physical means

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What is the composition of matter?

• Matter

Pure Substance
Mixture
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Mixture

• A mixture is made up of two or more substances
  that are not chemically combined.
• Mixtures can be separated by simple physical
  means.
• e.g. sand and salt, salad

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Mixtures

• Two mixtures containing the same substances may
  not have the same proportions.
• Example not all salads have the same amount of
  tomatoes, but they are all salads

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Water and Food Coloring Mixture

• Two mixtures of the same substances may have
  different proportions.

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Mixtures
Mixtures
Homogeneous
Heterogeneous
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Homogeneous Mixture

• Homogeneous mixtures are uniform in composition,
  i.e. particles are evenly spread throughout and
  you cant see any differences
• They have the same proportion of components
  throughout.
• Examples
• - Salt water - Sugar water
• - Air - Carbonated water

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Solution

• A homogeneous mixture when two or more
  substances are evenly distributed in one
  another.

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Alloy

• A solid or liquid mixture of two or more metals
  (e.g. brass, bronze)
• Is a solution, because particles are evenly
  spread

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Homogeneous Mixture
Solution
Alloy
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Heterogeneous Mixture

• Heterogeneous mixtures are not uniform
  throughout you can see differences
• Molecules are not evenly spread
• If the particles settle over time, its called a
  suspension (if they dont settle, its called a
  colloid)

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What is a suspension?

• A mixture in which particles settle over time.
• Examples Orange juice with pulp and muddy water

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Heterogeneous Mixture
colloid
Suspension
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Working backwards...4 examples
Matter
Pure substance
Mixture
homogeneous
heterogeneous
element
compound
suspension
solution
alloy
atom
molecule
Italian salad dressing
brass
black coffee
gold
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What is a colloid?

• A heterogeneous mixture suspension where the
  particles are small enough not to settle.
• May appear to be the same throughout but it is
  not!
• Examples
• -Fog -Jello
• -Paint -Smoke
• -Whipped cream -Marshmallow

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Tyndall Effect

• Sometimes the particles are too small to see.
• Light does not pass through colloids because
  their particles scatter light.
• This is called the Tyndall Effect.

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What is an emulsion?

• A special case of a colloid
• A mixture of two immiscible liquids (ones that
  usually dont mix)
• Examples mayonnaise, butter, whole milk