Term | Definition |
acid | molecule that donates hydrogen ions and increases the concentration of hydrogen ions in a
solution |
adhesion | attraction between water molecules and other molecules |
aliphatic hydrocarbon | hydrocarbon consisting of a linear chain of carbon atoms |
anion | negative ion that is formed by an atom gaining one or more electrons |
aromatic hydrocarbon | hydrocarbon consisting of closed rings of carbon atoms |
atom | 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 reactions | statement of a chemical reaction with the number of each type of
atom equalized for both the products and reactants |
base | molecule that donates hydroxide ions or otherwise binds excess hydrogen ions and decreases
the concentration of hydrogen ions in a solution |
buffer | substance that prevents a change in pH by absorbing or releasing hydrogen or hydroxide ions |
calorie | 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 sides of the
tubes |
cation | 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 the
formation of molecules |
chemical reaction | process leading to the rearrangement of atoms in molecules |
chemical reactivity | the ability to combine and to chemically bond with each other |
chesion | intermolecular forces between water molecules caused by the polar nature of water;
responsible for surface tension |
compound | substance composed of molecules consisting of atoms of at least two different elements |
chemical bond | type of strong bond formed between two of the same or different elements; forms
when electrons are shared between atoms |
dissociation | 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 |
electrolyte | necessary for nerve impulse conduction, muscle contractions and water balance |
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 an
electron is most likely to be found |
electron transfer | movement of electrons from one element to another; important in creation of
ionic bonds |
electronegativity | 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 |
electron | 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 |
element | one of 118 unique substances that cannot be broken down into smaller substances; each
element has unique properties and a specified number of protons |
enantiomers | 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 |
equilibrium | steady state of relative reactant and product concentration in reversible chemical
reactions in a closed system |
evaporation | separation of individual molecules from the surface of a body of water, leaves of a
plant, or the skin of an organism |
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 |
hydrocarbon | molecule that consists only of carbon and hydrogen |
hydrogen bond | weak bond between slightly positively charged hydrogen atoms to slightly
negatively charged atoms in other molecules |
hydrophilic | describes ions or polar molecules that interact well with other polar molecules such as
water |
hydrophobic | describes uncharged non-polar 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 |
ionic bond | chemical bond that forms between ions with opposite charges (cations and anions) |
Ion | atom or chemical group that does not contain equal numbers of protons and electrons |
irreversible chemical reaction | chemical reaction where reactants proceed uni-directionally to
form products |
isomers | molecules that differ from one another even though they share the same chemical formula |
isotope | 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 that has been treated with a natural water-soluble dye that
changes its color as the pH of the environment changes so it can be used as a pH indicator |
mass number | total number of protons and neutrons in an atom |
matter | anything that has mass and occupies space |
molecule | two or more atoms chemically bonded together |
neutron | uncharged particle that resides in the nucleus of an atom; 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 |
nucleus | 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 |
orbital | region surrounding the nucleus; contains electrons |
organic molecule | any molecule containing carbon (except carbon dioxide) |
pH paper | see litmus paper |
pH scale | scale ranging from zero to 14 that is inversely proportional to the concentration of
hydrogen ions in a solution |
periodic table | organizational chart of elements indicating the atomic number and atomic mass of
each element; provides key information about the properties of the elements |
polar covalent bond | type of covalent bond that forms as a result of unequal sharing of electrons,
resulting in the creation of slightly positive and slightly negative charged regions of the molecule |
product | molecule found on the right side of a chemical equation |
proton | positively charged particle that resides in the nucleus of an atom; has a mass of one amu and a
charge of +1 |
radioisotope | isotope that emits radiation composed of subatomic particles to form more stable
elements |
reactant | molecule found on the left side of a chemical equation |
reversible chemical reaction | chemical reaction that functions bi-directionally, where products
may turn into reactants if their concentration is great enough |
solvent | 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 molecules of the liquid |
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 |