Biology CH2a

Element - cannot be broken down into other substances by chemical reactions

Matter - anything that takes up space and has mass

Chemistry - the study of matter

compound - 2 or more elements in a fixed ratio

atom - smallest unit having the properties of an element

subatomic particles - the composition of an atom, protons, electrons, neutrons 

Proton - in center of atom, positive charge, 1 dalton, determines chemical identity

Electron - orbits the nucleus, negative charge, negligible mass, move at speed of light

Neutron - in center of atom, no charge, 1 dalton

Atomic mass - number of protons and neutrons

Atomic Number - number of neutrons

isotope - different atomic form of same element, same # of protons but diff # of neutrons

electron shell - represent energy levels

valence shell - outermost shell and contains valence e-

valence electrons - outermost electrons with high energy

covalent bond - sharing of pair valence e- between two atoms (strongest bond)

hydrogen bond - a weak bond, partial pos hydrogen is attracted to electronegative atom

ionic bond - attraction between oppositely charged ions (medium strength)

ion - charged atom/molecule

molecule 0- made of 2 or more atoms, covalent bond

electronegativity - affinity for e- (the more electronegative, the more it pulls shared e- to itself)

polar covalent bond = between elements with different electronegative values

nonpolar covalent bond - occurs between elements that have the same electronegativity

Van Der Waals interaction - weak attraction when atoms are so close that outer electron shells barely touch

cohesion - hydrogen bonds cause water molecules to stay close to eachother

adhesion - clinging of one substance to another

surface tension - measure of how difficult it is to stretch or break the surface of a liquid

Kinetic Energy - energy of motion

Thermal Energy - kinetic energy associated with the random movement of atoms or molecules

Temperature - average kinetic energy of the molecule in a body of matter

heat- molecule movement, large amount of energy required to disrupt h2o

calorie - energy required to raise 1 gram of water 1C

kilo calorie - food calorie, 1000 calorie

specific heat - amount of heat that must be absorbed or lost for 1g of substance to change 1C

Heat of vaporization - energy needed to go from liquid to gas

solvent - dissolving agent of a solution

solute - substance that is dissolved 

solution - liquid that is homogenous mixture of 2 or more substances

aqueous solution - water is solvent

hydrophilic - attraction to water and will dissolve in water(polar, ionic)

hydrophobic - not attracted to water and will not dissolve in water (non polar)

acid - compound that ionizes to release hydrogen ion and increase h+ in outside solution

base - compound that ionizes to release OH- or directly combines with H+ to decrease H+

alkaline - just a base

pH - hydrogen potential, measure of hydrogen ion concentration

buffer - substances that can resist charges in pH

Acid rain - rain with pH of 4.5 and below

ocean acidification - ocean absorption of CO2 combining with water to form carbonic acids