BIO CH 3

Polarity allows

Water molecules to form hydrogen bonds with each other

Polarity of water

Electrons of the polar covalent bonds spend more time near oxygen than hydrogen= water polar molecule

4 water properties

-Ability to moderate temperature -cohesive behavior -expansion upon freezing -versatility as a solvent

Cohesion

Hydrogen bonds hold water molecules together (results in surface tension)

Moderation of temp by water

Water absorbs heat from warmer air and releases started heat to cooler air

PH scale

Determines whether a solution is acidic or basic

Acid

Substance that increases H+ concentration of a solution

Base

A substance that reduces H+ concentration of a solution

Acidic PH value

Values less than 7

Basic PH value

Value greater than 7

Acidic examples

Food

Neutral examples

Human

Basic examples

Cleaning supplies

Buffers

Substances that minimize changes in concentrations of H+ and OH- in a solution

Most buffers have

A weak acid and corresponding base