Properties of Water and pH

http://www.youtube.com/watch?v=aVmU3CLxvgU

Van der Waals Forces

• Van der Waals forces- force between molecules due to intermolecular attraction.

Hydrogen Bonding

• Hydrogen bonding- a type of intermolecular attraction due to differences in electronegativity between a polar molecule that contains hydrogen and an atom in another polar molecule.

Properties of Water• ALL a result of water’s ability to hydrogen

bond!• Cohesion• Adhesion– Capillary action

Properties of Water

• Heat capacity

• Expands when frozen• Ice is less dense than water

Mixtures of Water• Solutions- all components are evenly distributed.– Solute– Solvent

• Suspensions- all components are NOT evenly distributed, water and nondissolved material.

Example of both a solution and a suspension: blood

pH Scale

• Indicates the concentration of H+ in a solution.pH = -log [H+]

Buffers

Buffers

• Weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH.

• Buffers dissolved in living organisms play an important role in maintaining homeostasis in organisms.