AP Environmental Science Chapter 2: Environmental Systems

Matter

has mass and takes up space

Mass

measurement of matter (kg)

Weight

how mas is effected by gravity

Atom

smallest particle that can be an element

Molecule

multiple atoms

Element

multiple molecules; 94 naturally occuring, 24 man made

Compound

molecules containing more than one element

Nucleus

core containing protons and neutrons

Protons

postive charge, defines atomic number

Neutrons

neutral charge, more or less create isotopes

atomic number

number of protons

isotopes

elements with more or less than usual neutrons

Radioactive Decay

Radioactive (unstable) isotopes spontaneously release material from the nucleus

Half-Life

amount of time it takes for half of the material in an element to decay

y=x(.5)^z

when y=current amount of material, x=starting amount of material, and z=the number of half-lives passed in a given amount of time

Carbon Dating

Calculates the proportion of carbon-14 in dead biological material to see how long it has been dead

Oribitals

Electron clouds

Covalent Bonds

Shared electrons

ex) Methane

Ionic Bonds

Transferring electrions so that one becomes positively charged and the other negatively charged; not as strong as covalent

ex) Sodium Chloride

Hydrogen Bonds

weak, covalent bonds including hydrogen

organic compounds

carbon-carbon or carbon-hydrogen bonds

Lipids

non soluble

Nucleic Acids

DNA/RNA

Polar Molecule

One side is more positive and the other side is more negative ex) water

Surface Tension

Results from cohesion of water molecules at the surface

Capillary Action

results when water molecules are more attracted to other molecules than to each other

Boiling Point and Freezing Point

100C/212F=water becomes a gas

0C/32F=water becomes a solid

Solvent

Water=Universal Solvent

Acid

contributes hydrogen ions to a solution; when dissolved in water it separates into H+ and negatively charged ions

Base

contributes hydroxide ions to a solution; when dissolved in water it separates into OH- and positively charged ions

pH scale

logarithmic scale, so each # on the scale is a factor of 10

ex) 4 is ten times as acidic as a 5

above 7=Basic

below 7=Acidic

7= Water

Chemical Reaction

occurs when atoms separate from molecules they are a part of or recombine with other molecules

Law of Conservation of Matter

no matter created or destroyed

Inorganic Compounds

either do not contain carbon or contains carbon bound to elements other than hydrogen

Organic Compounds

carbon-carbon or carbon-hydrogen bonds are present

Carbohydrates

compounds composed of carbon, hydrogen, and oxygen atoms

ex) glucose (simple sugar)

Protein

made up of long chains containing nitrogen and organic molecules called amino acids

Enzymes

Proteins that control the rate of reactions

Cell

consists of four types of macromolecules and other substances surrounded by a membrane

Energy

ability to do work/transfer heat

Electromagnetic Radiation

a form of energy we percieve as heat

ex) light, ultraviolet, infrared

Photons

massless pockets of energy that travel at the speed of light and carry electromagnetic radiation

Wavelength

Determines the amount of energy carried in a photon

Joule

measure of energy

calorie

amount of energy it takes to raise 1 gram of water by 1 degrees C

1 calorie=4.184 J

Calorie

Food Calorie

1Calorie=1,000calories (1 Kilocalorie)

British Thermal Unit

amount of energy to raise 1 pound of water by 1 degree F

1BTU=1055J

Kilowatt-Hour

amount of energy used by running 1 Kilowatt of electricity for 1 hour

1kWh=3.6 Megajoules

Power

rate at which work is done

Energy=power*time

Power=Energy/time

Kinetic Energy

Energy in motion

Potential Energy

Energy stored

Chemical Energy

Potential energy stored between chemical bonds

Temperature

Kinetic Energy of a substance

First Law of Thermodynamics

The principle of conservation of energy. Energy can be transferred and transformed, but it cannot be created or destroyed.

Second Law of Thermodynamics

when energy is changed from one form to another, some useful energy is always degraded into lower quality energy (usually heat)

Energy Efficiency

ratio of the amount of work to total amount of energy expended

Energy Quality

the ease of use of an energy source (convienience, concentration, accessibility)

Entropy

a measure of the disorder of a system; increasing unless energy is added to create order

Open System

Exchanges in energy or matter occur across system boundaries; most systems are open

(sunlight, birds, water, migration all contribute to an open system)

Closed System

Matter and energy exchanged only within the system ex) some caves