70 terms

Chapter 2: Basic Chemistry

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matter
the "stuff" of the universe
energy
has no mass and does not take up space
potential energy
when energy is inactive or stored
chemical energy
stored in the bonds of chemical substances
electrical energy
results from the movement of charged particles
mechanical energy
energy directly involved in moving matter
radiant energy
travels in waves, that is, it is the energy of the electromagnetic spectrum
elements
all matter is composed of a limited number of substances called _____
periodic table
a complete listing of the elements
atoms
each element is composed of more or less identical particles or building blocks
atomic symbol
we designate each element by a one- or two- letter chemical shorthand
protons
have a positive charge
neutrons
are uncharged or neutral
electrons
have a negative charge
planetary model
portrays the atom as a miniature solar system in which the protons and neutrons are clustered at the center of the atom in the atomic nucleus
orbital model
this more modern model of the atomic structure is called ________
atomic number
each element is given a number called _______
atomic mass
the ________ of any atom is the sum of the masses of all the protons and neutrons contained
isotopes
have the same number of protons and electrons but vary in the number of neutrons they contain
radioisotopes
the heavier isotopes of certain atoms are unstable and tend to decompose to become more stable
radioactivity
process of spontaneous atomic decay
molecule
when two or more atoms combine
compound
when two or more different combine
electron shells
electrons occupy orbits or generally fixed regions of space around the nucleus
valence shell
the atom's outermost shell
ionic bonds
form when electrons are completely transferred from one atom to another
ions
charged particles
salts
sodium chloride and most other compounds formed by ionic bonding fall into the general category of chemicals called _______
covalent bonding
molecules in which atoms share electrons are called ________
hydrogen bonds
extremely weak bonds formed when a hydrogen atom bound to one electron hungry nitrogen or oxygen atom is attracted by another electron hungry atom
synthesis reactions
occur when two of more atoms or molecules combine to form a larger more complex molecule
decomposition reactions
occur when a molecule is broken down into smaller molecules , atoms or ions
exchange reactions
involve both synthesis and decomposition reactions
inorganic compounds
lack carbon and tend to be small, simple molecules
organic compounds
carbon-containing compounds
electrolytes
substances that conduct an electrical current in solution
acids
have a sour taste and can dissolve many metals
proton donors
acids are also defined as __________
bases
have a bitter taste , feel slippery, and are proton acceptors
proton acceptors
bases are also defined as __________
neutralization reaction
this type of exchange in which an acid and a base interact is more specifically called ________
pH
the relative concentration of hydrogen ions in various body fluids is measured in concentration units called _______
buffers
regulates acid-base balance
polymers
chainlike molecules made of similar or repeating units
dehydration synthesis
hydrogen atom is removed from one monomer and a hydroxyl group is removed from the other to be joined
hydrolysis
when polymers must be broken down to their monomers
carbohydrates
include sugars and starches, contain hydrogen, carbon, and oxygen.
monosaccharide
one sugar; simple sugars
disaccharides
double sugars are formed when two simple sugars are joined together by dehydration synthesis
polsaccharides
long, branching chains of linked simple sugars
lipids
large and diverse group of organic compounds
triglycerides
composed of two types of building blocks, fatty acids and glycerol
saturated
fatty acid chains with only single covalent bonds between carbon atoms
unsaturated
fatty acids chains with double bonds between the carbon atoms
trans fats
common in many margarines and baked products, are oils that have been solidified by addition of hydrogen atoms at sites of double-carbon bonds
omega-3 fatty acids
found naturally in cold-water fished, appear to decrease the risk of heart disease and some inflammatory diseases
phospholipids
are similar to the triglycerides, they differ in that it is always part of the molecule and takes place of one of the fatty acid chains
steroids
basically flat molecules formed of four interlocking rings
cholesterol
the single most important steroid molecule
proteins
account for over 50 percent of the organic matter in the body
amino acids
the building blocks of proteins are small molecules
alpha helix
the most common secondary structure
fibrous proteins
appear most often in body structures
globular proteins
mobile, generally compact, spherical molecules that have at least tertiary structure
functional proteins
the do things rather than just form structures
enzymes
functional proteins that act as biological catalysts
catalyst
a substance that increases the rate of a chemical reaction without becoming part of the product
nucleic acids
fundamental; they make up genes, which provide the basic blueprint of life
nucleotides
building blocks of nucleic acids
ATP
provides a form of chemical energy that all body cells use