Introduction to Matter

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Introduction to Matter
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Chemistry is the study of matter and how it
changes...

• Matter is anything that has mass and takes up
  space (or has volume).
• There are 3 topics you have studied which are not
  matter because they have no mass or volume. What
  do you think they are?
• Light
• Sound
• Electricity

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Atoms
Elements
Compounds
All compounds are molecules... but not all
molecules are compounds!!
Molecules
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ATOMS

• The smallest particle that has properties of an
  element is an atom!
• Atoms are matter!
• What are the parts of an atom?????

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ELEMENTS

• An element is a substance that cannot be broken
  down into a simpler substance.
• Each element has a one or two letter symbol.
• RELATIVE AMOUNTS OF THE ELEMENTS IN YOUR BODY

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COMPOUNDS

• A compound is a substance made of atoms of more
  than one element bound together.

H2O2
CO
O2
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MOLECULES

• Molecules are the smallest unit of a substance
  that exhibit all of the properties characteristic
  of that substance.

H2O
O2
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CHEMICAL FORMULAS

• A chemical formula is a written way to show what
  elements and how many atoms of an element are in
  a compound or molecule.

Example
2
2
or
stars
I can count that I have four stars
I have two to the second power in stars
or
H
H
H2
I can write the chemical formula by writing the
symbol for Hydrogen followed by a subscript that
shows how many atoms of hydrogen there are
I can count that I have two atoms of Hydrogen (H)
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Practice!

• Two atoms of Oxygen
• O2
• Four atoms of Carbon
• C4
• One atom of Chlorine
• Cl
• One atom of Carbon and two atoms of Oxygen
• CO2

If the chemical formula for a water molecule is
H2O, what does 3H2O mean???
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Pure Substances v. Mixtures

• A pure substance is matter with a fixed
  composition and definite properties. Compounds
  can be pure substances
• A mixture is a combination of more than one pure
  substance.

Which of these are Pure Substances and which are
Mixtures??
Cough Syrup
Water
Salt Water
Sugar
Apple Juice
Aluminum
Moving on...
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MIXTURE!!!
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PURE SUBSTANCE!!!
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Classification of Mixtures

• We can mix solids and liquids or liquids with
  liquids.
• If the substances are not uniformly mixed your
  substance is a heterogenous mixture.
• If the substances are uniformly mixed then your
  substance is a homogeneous mixture.
• Any part of a system that has uniform composition
  and properties is called a phase.
• A homogeneous mixture will have one phase.
• A heterogeneous mixture will have two or more
  phases.

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When dealing with liquid-liquid mixtures...

• A mixture with liquids that are miscible will
  dissolve into each other in various proportions.
• A mixture with liquids that are immiscible will
  not mix with one another.