Chemistry

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Chemistry
Chemical Reactions Solutions vs. Mixtures
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What do you think of when you hear CHEMISTRY?
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Chemistry is all around us!

• Food
• Photography
• Fisherman
• Medicines
• Textiles
• Playgrounds

A CHEMICAL IS ANY SUBSTANCE WITH A DEFINITE
COMPOSITION!
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Chemical Reactions Review!
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What is a Chemical Reaction?

• When a chemical reaction occurs, bonds between
  atoms are formed or broken.
• This causes substances to combine and recombine
  as different molecules.
• This happens a lot inside an organisms cells!
• All the chemical reactions that occur within an
  organism are referred to as that organisms
  METABOLISM!

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What is a Chemical Reaction?

• Scientists use chemical equations to represent
  the chemical reactions. (Kind of like in math!)

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How to Read a Chemical Equation

• Plants synthesize complex molecules, like starch,
  caffeine, and chlorophyll from simple molecules,
  like CO2 and H2O
• EX
• 6CO2 6H2O C6H12O6 6O2
• Here glucose (sugar) is made from CO2 and H2O!

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How to Read a Chemical Equation

• EX
• 6CO2 6H2O C6H12O6 6O2

Reactants Products
Yields
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Classification of Matter

• We can classify matter into one of three states
  (solid, liquid or gas), but this is very general!
• We also classify matter into one of four
  categories element, compound, mixture, or
  solution.
• Lets see how to do this!

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ELEMENTS

• An element is a substance that cannot be broken
  down into simpler chemical substances.
• There are 92 naturally occurring elements on
  earth and many synthetic elements as well.
• EX Gold, Carbon, Lead

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COMPOUNDS

• A compound is a substance that is composed of
  atoms of two or more different elements that are
  chemically combined.
• EX Water is a combination of oxygen atoms and
  hydrogen atoms.

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MIXTURES

• A mixture is a combination of substances in which
  individual components retain their individual
  properties.
• So the two substances are not chemically
  combined!
• EX Sand and sugar mixture you can still pick
  out the sand particles and the sugar grains.
  They do NOT make a new substance.

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SOLUTIONS

• A solution is a mixture in which one or more
  substances are evenly distributed in another
  substance.
• One substance is dissolved in another!
• EX Kool-Aid! The Kool-aid crystals dissolve in
  water making a tasty treat!

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Use your brain!

• Matter can be homogenous or heterogeneous!
• What do those words mean?
• Remember your roots!

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Did you figure it out?

• If something is HOMOGENOUS, that means it is the
  SAME throughout!
• If something is HETEROGENEOUS, that means there
  are different parts to it!

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Chemistry is interesting!
Study these notes tonight!