Energy and Matter Chapter 2.

Review!  Easter Island:  Colonized about 2,900 years ago  Soil and tree resources exhausted (Natural Capital)  Over 300 statues built to appease angry gods.  War over remaining resources, cannibalsim.

SCIENCE!

Science Vs. Junk  Junk science is untested ideas presented as sound science!  How reliable are sources making the claim? Do they have an agenda? Are they experts? What is their source of funding?  Do conclusions follow logically from the observations?  Has the claim been verified by impartial peer review?  How does the claim compare with the consensus view of experts in the field?

Matter and Compounds  Matter is anything that has mass and takes up space.  Elements are specific atoms of a given type  Compounds are forms when atoms of 2 elements form a covalent bond. –Ionic Compounds –Covalent Compounds

Atoms, Ions, Compounds  Atom: Smallest unit of matter that has characteristics of an element.  Ion: an atom that has lost or gained an electron. –Cation: Positive charge –Anion: Negative charge  When 2 ions form a bond, the result is a compound.

Compounds and Formulas  Each compound has a formula. –NO is Nitric Oxide. It is one Nitrogen and one oxygen. (Covalent) –KBr is Potassium Bromide and is one Potassium and one Bromine. (Ionic)  Hydrocarbons are compounds with carbon and hydrogen, like methane (CH 4 )  Chlorinated Hydrocarbons are compounds of carbon, hydrogen, and oxygen atoms.

Subatomics  Each atom has a small nucleus and surrounding cloud of electrons –Electrons are negative –Protons are positive –Neutrons have no charge at all.  Atomic number = # protons in nucleus (equal number of electrons…)  Atomic Mass = #protons + neutrons

Matter types

Physical and Chemcial Changes  Physical Changes do not change chemical composition. (melting, boiling)  Chemical Changes do, and are the result of a chemical reaction. (Combustion, Decomposition)

Law of Conservation of Matter  When a chemical or physical change occurs, no atoms are created or destroyed.  There is no away to “throw away”  Undesirable, dangerous, or damaging chemical products are called Pollutants.

Types of Pollutants  The law of conservation of matter means that we will always have pollutants and must come up with a way to manage what we do produce.  Persistence is a measure of how long the pollutant stays in the air, water, soil, or body.

Types  Degradable, nonpersistent: broken down completely or reduced to acceptable levels by natural processes.  Biodegradable: Broken down by living organisms.  Slowly degradable, persistent: Takes decades to degrade.  Non-degradable: Cannot be broken down.