The Chemistry of Life

1
The Chemistry of Life

• Biology

2
The Nature of Matter
3
Atoms

• Basic unit of matter
• Protons
• charge
• In nucleus
• Neutrons
• No charge
• In nucleus
• Electrons
• - charge
• Around nucleus

4
Elements

• Pure substance of only one atom

5
Compound

• 2 or more elements combined
• Some other examples?

Sodium chloride (NaCl) salt
6
Chemical Bonds

• Ionic
• Electrons transferred from one atom to another
• Ex NaCl (salt)
• Covalent
• Electrons are shared between atoms
• Ex water (H2O)

7
Properties of Water
8
Why is water important?

• DONT WRITE THESE DOWN
• Water is 70 of our total body weight
• 75 of the Earth is covered in water
• A person can live without food for more than a
  month but can only live without water for one
  week
• All cells contain water and most are bathed in it
• Many chemical reactions have water as a reactant
  or product
• Many reactions occur in water

9
Some important terms

• Mixture a material composed of two or more
  elements or compounds that are physically mixed
  together but not chemically combined (ex. Sugar
  and sand)
• Solute the substance that is dissolved (ex.
  Salt)
• Solvent the substance in which the solute
  dissolves (ex. Water)
• Solution mixture of two or more substances in
  which the molecules of the substances are evenly
  distributed (ex. Salt water)
• Suspension mixture of water and an non-dissolved
  materials (ex. Oil and water)

10
As a solvent.

• Excellent because it is polar
• Polar ? a more negative side of the molecule and
  a more positive side of the molecule

11
Properties of Water
12
1. Cohesive Forces

• Water sticks to itself due to hydrogen (H) bonds
• Weak attractions between and poles of water
  molecules

Hydrogen bonds
13
2. Adhesive forces

• Water sticks to other charged substances
• This is why water makes things wet

14
3. Surface tension

• Water molecules push and pull at each other

15
4. Capillary action

• Adhesion cohesion together push water around
• Water rises in very fine tubes
• Microscopic spaces soil, plants, etc.

How water rises through stems of plants to their
leaves