Water

An extremely unusual chemical

Covalent Bonds

• Share electrons• “complete” one

another• Strong – hard to break

Heat capacity

• Ability to hold onto a large amount of heat

• Takes a lot of energy to raise the temperature of water

• Importance to living things?

Phoenix

Atlanta

Boise, Idaho

Providence, RI

Average daily high: 225oFAverage daily low: -243oF

So the big so what?

• Water in the atmosphere helps to moderate climate.– Kept within reasonable limits

Latent Heat

• Water gives off a large amount of heat when it changes phases

• Importance to living things?

HOMEOSTASISMaintaining steady internal

conditions

But…all is not equal

• Unequal electronegativity– Ability to attract

electrons• Do not share electrons

equally

SO WHAT?

Polar Covalent Bonds

• Unequal sharing of electrons

• Creates oppositely charged poles

• Opposites attract• Like a chemical magnet• Creates hydrogen

bonding

So What?

• Universal Solvent– Can exchange nutrients– Can exchange waste

So What?

• Medium for chemical reactions

• Participant in chemical reactions– Product of

photosynthesis = oxygen

So What?

• Adhesion

So What?

• Cohesion

So what?

• Paper clip challenge– Addition of soap

So What?

• Capillary Action

So What?

• Density