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Biology 2e

Key Terms

Biology 2eKey Terms

molecule that donates hydrogen ions and increases the concentration of hydrogen ions in a solution
attraction between water molecules and other molecules
aliphatic hydrocarbon
hydrocarbon consisting of a linear chain of carbon atoms
negative ion that is formed by an atom gaining one or more electrons
aromatic hydrocarbon
hydrocarbon consisting of closed rings of carbon atoms
the smallest unit of matter that retains all of the chemical properties of an element
atomic mass
calculated mean of the mass number for an element’s isotopes
atomic number
total number of protons in an atom
balanced chemical equation
statement of a chemical reaction with the number of each type of atom equalized for both the products and reactants
molecule that donates hydroxide ions or otherwise binds excess hydrogen ions and decreases the hydrogen ions' concentration in a solution
substance that resists a change in pH by absorbing or releasing hydrogen or hydroxide ions
amount of heat required to change the temperature of one gram of water by one degree Celsius
capillary action
occurs because water molecules are attracted to charges on the inner surfaces of narrow tubular structures such as glass tubes, drawing the water molecules to the tubes' sides
positive ion that is formed by an atom losing one or more electrons
chemical bond
interaction between two or more of the same or different atoms that results in forming molecules
chemical reaction
process leading to rearranging atoms in molecules
chemical reactivity
the ability to combine and to chemically bond with each other
intermolecular forces between water molecules caused by the polar nature of water; responsible for surface tension
substance composed of molecules consisting of atoms of at least two different elements
covalent bond
type of strong bond formed between two atoms of the same or different elements; forms when electrons are shared between atoms
release of an ion from a molecule such that the original molecule now consists of an ion and the charged remains of the original, such as when water dissociates into H+ and OH-
ion necessary for nerve impulse conduction, muscle contractions, and water balance
negatively charged subatomic particle that resides outside of the nucleus in the electron orbital; lacks functional mass and has a negative charge of –1 unit
electron configuration
arrangement of electrons in an atom’s electron shell (for example, 1s22s22p6)
electron orbital
how electrons are spatially distributed surrounding the nucleus; the area where we are most likely to find an electron
electron transfer
movement of electrons from one element to another; important in creating ionic bonds
ability of some elements to attract electrons (often of hydrogen atoms), acquiring partial negative charges in molecules and creating partial positive charges on the hydrogen atoms
one of 118 unique substances that cannot break down into smaller substances; each element has unique properties and a specified number of protons
molecules that share overall structure and bonding patterns, but differ in how the atoms are three dimensionally placed such that they are mirror images of each other
steady state of relative reactant and product concentration in reversible chemical reactions in a closed system
change from liquid to gaseous state at a body of water's surface, plant leaves, or an organism's skin
functional group
group of atoms that provides or imparts a specific function to a carbon skeleton
geometric isomer
isomer with similar bonding patterns differing in the placement of atoms alongside a double covalent bond
heat of vaporization of water
high amount of energy required for liquid water to turn into water vapor
molecule that consists only of carbon and hydrogen
hydrogen bond
weak bond between slightly positively charged hydrogen atoms and slightly negatively charged atoms in other molecules
describes ions or polar molecules that interact well with other polar molecules such as water
describes uncharged nonpolar molecules that do not interact well with polar molecules such as water
inert gas
(also, noble gas) element with filled outer electron shell that is unreactive with other atoms
atom or chemical group that does not contain equal numbers of protons and electrons
ionic bond
chemical bond that forms between ions with opposite charges (cations and anions)
irreversible chemical reaction
chemical reaction where reactants proceed unidirectionally to form products
molecules that differ from one another even though they share the same chemical formula
one or more forms of an element that have different numbers of neutrons
law of mass action
chemical law stating that the rate of a reaction is proportional to the concentration of the reacting substances
litmus paper
(also, pH paper) filter paper treated with a natural water-soluble dye that changes its color as the pH of the environment changes in order to use it as a pH indicator
mass number
total number of protons and neutrons in an atom
anything that has mass and occupies space
two or more atoms chemically bonded together
uncharged particle that resides in an atom's nucleus; has a mass of one amu
noble gas
see inert gas
nonpolar covalent bond
type of covalent bond that forms between atoms when electrons are shared equally between them
core of an atom; contains protons and neutrons
octet rule
rule that atoms are most stable when they hold eight electrons in their outermost shells
region surrounding the nucleus; contains electron(s)
organic molecule
any molecule containing carbon (except carbon dioxide)
periodic table
organizational chart of elements indicating each element's atomic number and atomic mass; provides key information about the elements' properties
pH paper
see litmus paper
pH scale
scale ranging from zero to 14 that is inversely proportional to the hydrogen ions' concentration in a solution
polar covalent bond
type of covalent bond that forms as a result of unequal electron sharing, resulting in creating slightly positive and negative charged molecule regions
molecule that is result of chemical reaction
positively charged particle that resides in the atom's nucleus; has a mass of one amu and a charge of +1
isotope that emits radiation comprised of subatomic particles to form more stable elements
molecule that takes part in a chemical reaction
reversible chemical reaction
chemical reaction that functions bidirectionally, where products may turn into reactants if their concentration is great enough
substance capable of dissolving another substance
specific heat capacity
the amount of heat one gram of a substance must absorb or lose to change its temperature by one degree Celsius
sphere of hydration
when a polar water molecule surrounds charged or polar molecules thus keeping them dissolved and in solution
structural isomers
molecules that share a chemical formula but differ in the placement of their chemical bonds
substituted hydrocarbon
hydrocarbon chain or ring containing an atom of another element in place of one of the backbone carbons
surface tension
tension at the surface of a body of liquid that prevents the molecules from separating; created by the attractive cohesive forces between the liquid's molecules
valence shell
outermost shell of an atom
van der Waals interaction
very weak interaction between molecules due to temporary charges attracting atoms that are very close together
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