Chemistry Review

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Chemistry Review
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What is matter?

• anything that takes up space has mass.
• EVERYTHING IS MADE OF MATTER!!!

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So what is matter made of?

• ATOMS!!

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What does an atom look like?

• we dont really know what atoms look like, but
  we do know what they are made of!
• This is just a model-

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The 3 subatomic particles of an atom

1. Proton has a charge, is in the nucleus.
2. Neutron has a neutral charge is also in the
   nucleus.
3. Electron has a charge and is in the electron
   cloud around the nucleus, usually in specific
   levels.

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So how do atoms make all this stuff?

• There are over 100 different ELEMENTS.
• These elements bond with other atoms, maybe of
  different elements or the same elements, and make
  COMPOUNDS.
• Compounds act differently then the atoms they are
  made of.

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• Whenever atoms bond or a bond is broken some
  energy may be absorbed stored or some energy is
  released.

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So what is a compound?

• 2 or more atoms that are chemically bonded.
• (Compounds can be created or broken down
  chemically, elements cant be broken down.)

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What are 2 main types of chemical bonds?

1. Ionic 1 atom loses electron(s) 1 atoms gains
   electron(s)
2. Covalent the atoms share electrons.

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Ionic bond

• Sodium loses an electron, chlorine gets those
  electrons.
• Sodium becomes charged, chlorine becomes
  chargedand now the opposites are attracted to
  each other.

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Covalent Bond

• The oxygen and hydrogen atoms share electrons.

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Ummwhy are we learning about chemistry in
biology?
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• Every biological process is part of a chemical
  reaction!
• All of the energy we need depends on chemical
  reactions!

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• 5 elements make up over 90 of your body!
• C, H, N, O, P
• (Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorous)

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What about pH stuff?

• pH is the measure of the amount of hydrogen ions
  (H) in a solution.
• Lots of H makes a solution acidic.
• Lots of OH- (hydroxide ions) makes a solution
  basic (or alkaline)

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What about acids?

• They have a pH between 0 6 on the pH scale.
• They taste sour.
• They are corrosive (especially the really acidic
  things).

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What about bases?

• They have a pH between 8 14 on the pH scale.
• They taste bitter are slippery.
• They are also corrosiveespecially the really
  basic ones!

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What is 7 on the pH scale?

• 7 neutralpure water is an example.

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Why is pH important in biology?

• Many of the chemical reactions that take place
  can only occur at certain pHs.
• Also some things in the environment are damaged
  by pH changes.

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The pH scale