BIOL-1010 Water

General Info

Adhesion: water molecule’s ability to stick to OTHER surfaces (not itself)

Cohesion: individual water molecule’s ability to stick to other water molecules through hydrogen bonding

Surface Tension: is a measure of how hard it is to break the surface of a liquid (related to cohesion)

A large mount of energy is required to change the temperature of water
Water retains heat and slowly releases it
Oceans keep the Earth at a relatively constant temperature
Heat of vaporization is the heat a liquid must absorb to be converted to gas
As water evaporated, heat is removed and the surface cools (evaporative cooling)
^ helps stabilize internal temperatures in organisms

Solid water is less dense than liquid water.

Bodies of water freeze from the top down
If ice sank, all bodies of water would eventually freeze solid making life impossible on earth.
Ice (Hydrogen bonds are stable)
Water (not stable; break and reform)
Water is the universal solvent
- Dissolves polar molecules & ions
- dissolved ions surrounded by hydration shells
Water organizes nonpolar molecules
- Hydrophilic “water-loving” - polar
- Hydrophobic “water-fearing” - nonpolar
- Water causes hydrophobic molecules to aggregate or assuming specific shapes
Water can form ions even though it is a covalent molecule
- Hydronium (H^+)
- Hydroxide (OH^-)
- water is a rule breaker

Solution: homogenous mixture of substances (no longer see the separate pieces once mixed)

Solvent: dissolving agent of a solution

Solute: substance that is dissolved

Aqueous Solution: water is the solvent

Polar and nonpolar solutions do not mix.

pH scale: used to measure degree of acidity

ranges from 0-14

pH = measure of (H^+)