Properties of Water Essential Standard Bio.4.1 Understanding how biological molecules are essential to the survival of living organisms.

Water Chemical reactions of living things take place in aqueous environment Many unique properties

1. Polarity Polarity - sharing of atoms unequally Water shares hydrogen atoms unevenly Oxygen atom is negatively charged Polar substances dissolve in polar substances (water) Nonpolar – sharing of atoms equally Nonpolar substances do not dissolve in water

2. Hydrogen Bonding Hydrogen bonds – weak bonds between hydrogen of one molecule and oxygen of another molecule

3. Attractive Forces Cohesion – attraction between like substances Creates surface tension Adhesion – attraction between unlike substances Capillarity – ability of substance to draw another substance into it

4. Temperature Moderation Temperature does not experience significant change until after hydrogen bonds break Requires lots of heat!