Transcript Some Basic Chemistry

Some
Basic
Chemistry
Review Terms
• Elements
• Atom
• Atomic Mass
• Atomic Number
• Isotope
• Electron Shells
• Compound
• Molecule
• Molecular
Mass
• Chemical
Reactions
• Solute
• Solvent
Bonds
• Ionic Bonds- Transfer of
electrons
Bonds
• Covalent- Sharing of
electrons
–Polar- Shared unequally
–Nonpolar- Shared equally
Nonpolar
Polar
Bonds
• Hydrogen Bond- Between
hydrogen of one molecule and
oxygen or nitrogen of another
molecule
Sketch a molecule of water.
Consider:
• The type of bond that holds atoms
within a molecule of water together
• The type of bond that holds
molecules of water together
• How many water molecules can
bind together?
Water
• 75% of a cell is water
• Polar Covalent Bond (Oxygen
is negative)
• Any 1 water molecule can
form up to 4 hydrogen bonds
Water
• Water is both cohesive and
adhesive
Water
• Cohesion- holding together of
like substances
Water
• Surface Tension- Due to
cohesion
Water
• Adhesionholding
together of
different
substances
Water
• Capillary
Action:
Allows
water to rise
against
gravity
Water
• Has high Specific Heat
• Takes a lot of heat to raise its
temperature and cools more
slowly
• High Thermal Conductivityheat spreads quickly
Water
• A good Evaporative Coolant
• Water vapor carries away a
lot of heat. (molecules with
most energy go away, taking
heat)
Water
• Allows organisms to stay cool
Panting
Sweating
Water
• Water is a solvent of ions and
other polar molecules
• Nonpolar substances do not
dissolve (fats and oils)
pH Scale
• Measures the amount of H+
and OH- ions in water.
• Acids release more H+ ions
• Bases release more OH- ions
(or one that accepts more H+)
Buffers
• Keep pH consistent
• Take up or release H+ ions or
OH- ions