Some Basic Chemistry

Review Terms Elements Molecule Atom Molecular Mass 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 Adhesion- holding 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 Conductivity- heat 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 Sweating Panting

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