1. I.N. 22 LIVING THINGS: Properties of Water And Acids/Bases Headings
Vocabulary
Important Words

2. Living Things Use & Need Energy
a.) Energy comes from food, used to maintain body b.) AUTOTROPH: produce own food c.) HETEROTROPH: must consume food d.) DECOMPOSER: breaks down dead material for food

3. Living things respond to their surrounding
a.) Rxn to a stimulus
b.) Action causes a rxn
c.) Rxn is called a: Response
d.) Involves one individual

4. Question: Describe the properties of water that make it important to living things.
Water is Polar:
It has an uneven distribution of electrons between the hydrogen and oxygen atoms
One side is positive
Other is negative

5. Water Properties: Water is cohesive Cohesion:
attraction B/T same molecules
causes molecules to draw inward at surface
Ex: Some insects & spiders can “walk” on the surface of H2O
Water is adhesive
Adhesion:
attraction between different mol.
causes H20 to bend at surface
Ex: capillary action-pulls column of water up to the top of a plant
Water Properties:

6. Water is called “Universal solvent”: dissolves many other substances due to polarity
Differences in charges pulls/pushes substances apart
Water exhibits evaporative cooling: removes heat when it evaporates from a surface
Ex: sweating cools skin
Water expands during freezing: expands into crystal formation releasing heat
Ex: rocks broken up by ice creating soil; ice layer protects fruit from freezing

7. Acids, Bases and the pH scale
The pH scale measures the concentration of H+ ions (how acidic something is)
Ranges from 0-14
At 7: H+ ions and OH- ions are equal so it is neutral
0-7: Acidic, has more H+ ions
7-14: Basic, has more OH- ions

8. ACIDS: release H+ when mixed with water
Sour, corrosive
Ex: HCl, H2SO4
Always have H at front of formula
BASES: release OH- when mixed with water
Bitter, slippery, usually in cleaners
NaOH, CaOH
Always have OH at end of formula

9. What is a buffer?
Buffers are weak acids or bases that react w/strong acids and bases
prevent sharp changes in pH
Helps to neutralize pH
Helps control pH in blood, digestive tract, etc. = maintain Homeostasis