37 terms

Chapter 2: Water and Life

STUDY
PLAY
matter
anything that occupies space and has mass
element
a substance that cannot be broken down into other substances by chemical reactions
trace elements
essential for life and only needed in small amounts (iodine & fluorine )
compound
substance that contains two or more elements in a fixed ratio
atoms
smallest unit of matter that still retains the properties of an element
proton
positively charged subatomic particle in the nucleus, 1 amu
neutron
neutrally charged subatomic particle in the nucleus, 1 amu
electron
negatively charged subatomic particle in a cloud outside the nucleus 1/2000 amu
nucleus
center of an atom made up of protons and neutrons
atomic number
number of protons which determines the type of element formed by the atom
mass
measure of the amount of material in an object
mass number
number of protons and neutrons in the nucleus of an atom
isotopes
alternate mass forms of an element
radioactive isotopes
decays spontaneously, giving off particles, and energy
chemical bonds
attractions between atoms due to the behavior of electrons
ions
charged atom that has gained or lost electrons
ionic bond
the transfer of an electrons between oppositely charged ions
covalent bond
when two or more atoms share one or more pairs of outer shell electrons
molecules
atoms held together by covalent bonds
hydrogen bonds
the weak attraction between the positive and negative of polar molecules due to unequal sharing of electrons
chemical reactions
rearrange molecules by breaking existing chemical bonds and forming new one.
reactants
the substances that enter the chemical reaction
products
the end materials of the chemical reaction
cohesion
tendency of molecules of the same kind to stick together
surface tension
a measure of how difficult or easy it is to stretch or break the surface of a liquid
adhesion
tendency of molecules to stick to molecules of a different kind
heat
the amount of energy associated with the movement of the atoms and molecules in a body of matter
temperature
measures the intensity of heat
evaporative cooling
occurs when a substance evaporates and the surface of the liquid remaining behind cools down.
solution
liquid consisting of a homogeneous mixture of two or more substances
solvent
dissolving agent
solute
dissolved substance
aqueous solution
when water is the solvent
acid
chemical compound that releases hydrogen ions to a solution (1-6 on the pH scale)
base
chemical compound that accepts hydrogen ions and removes them from a solution (8-14 on the pH scale)
pH Scale
measures the inverse log of hydrogen ion concentration
buffers
substances that resist changes in pH