Ap bio properties of water/chem stuff

Covalent bonds

2+ atoms share electrons

Ionic bonds

attraction between oppositely charged molecules, usually between a metal and non-metal

Hydrogen bonds

partially positive hydrogen atoms in one polar covalent molecule will be attracted to an electronegative atom in another polar molecule

Polarity

Polar covalent bonds created by unequal sharing of electrons between oxygen and hydrogen within a water molecule

cohesion

attraction of molecules for other molecules of the same kind

What holds H20 molecules together and increases cohesive forces

hydrogen bonds

What do cohesion and adhesion allow for

movement of water and nutrients against gravity

What causes surface tension

cohesion/hydrogen bonds

Adhesion

the attraction to other molecules that are polar or have charge

Capillary action

upward movement of water against gravity due to the forces of adhesion, cohesion, and surface tension, can only occur when adhesion is greater than cohesion

High specific heat

H20 resists change in temperature due to hydrogen bonds

uses for high specific heat

moderates air temp, stabilizes ocean temp

High heat of vaporization

water requires a large amount of energy to evaporate due to strong hydrogen bonds

what does high heat of vaporization leaed to

evaporative cooling: water molecules expand, as a result the surface they evaporate from gets cooler

Density

As water solidifies(becomes ice), it expands and becomes less dense due to hydrogen bonding

What does density allow for

Allows marine life to live in insulated environments under a sheet of ice, since ice is less dense than water

pH and buffering

water can disasociate into hydrogen and hydroxide ions, which creates a chemical balance that defines whether a solution is neutral, acidic, or basic