Chapter 3: Water and the fitness of the enviroment

Water (H2O)

• a polar covalent bond

Water propterties

• all a result of hydrogen bonding with water molecules.

cohesion

• water molecules being attracted to each other (forms bodies of water, droplets, etc)

• Water sticking to water- hydrogen bonding

Adhesion

• water sticking to other polar molecules (through hydrogen bonding

• Ex: water sticking to your skin- hydration 

Capillary Action

• Water moving up a small tube despite gravity

• due to: cohesion, adhesion, and hydrogen bonding

• Ex: water going up a tree

Water has a high specific heat

• Amount of heat needed to raise 1 gram of substance to 1°C

• Water resists temp changes maintains homeostasis

• Ex: Human body temp is stable.

Water stabilizes climate/temp

• leads to climate moderation

• water absorbs a lot of heat energy without changing temp

Ice floats(water expands when it freezes)

• The distance between water molecules INCREASES from liquid to solid

• Why?- Hydrogen bonding

Water is the universal solvent

Solute: Material being dissolved (Salt)

Solvent: Liquid (water) doing the dissolving 

Solution: a homogeneous mixture of both

Hydrophilic: attracted to water

Hydrophobic: not attracted to water

Solution Concentration

• usually based on morality

• Morality- numbers of moles of solute per liter of solution

Moles

The molecular weight of a substance in grams

P^H

• Power or potential of hydrogen

• measure of [H^t] in a solution

• Dissociation: water can split into two ions

PH scale

measures the amount of H^t or H3O^t in a solutution

Buffers

• Materials that have both acid and base properties

• Resist PH shifts

• Cells and other biological solutions often contain buffers to prevent damage

Ocean Acdifcation

as a result of the burning of fossil fuels, more CO2 is trapped in the ocean