Terms | Definitions |
alchemist | a medieval version of the modern chemist; a practitioner who blended primitive chemistry with magic, seeking to turn ordinary metals into gold |
allotropes | different structural forms of the same element; for example, some carbon molecules form soft graphite, where as others form hard diamond |
alloy | a mixture consisting of a metal and one or more elements |
amorphous | something that has no specific shape; for example, a liquid or gas |
anhydrous | a chemical compound that normally has water molecules attached to its ions but from which the water has been removed |
Archimedes' principle | the Greek mathematician Archimedes stated that the buoyant force on an object in a fluid is equal to the weight of the fluid displaced by the object |
atomic number | the number of protons in an atom's nucleus |
average atomic mass | the average mass of an element is the average mass of the mixture of its isotopes |
balanced chemical equation | a chemical equation that has the same number of atoms of each element on both sides of the equation |
base | a substance that produces hydroxide ions (OH-) in solution; basic solutions have a pH over 7 |
Bernoulli's principle | Swiss scientist Daniel Bernoulli stated that as the velocity of a fluid increases, the pressure exerted by the fluid decreases (how airplanes fly) |
binary compound | a chemical compound composed of two elements; for example, sodium chloride (salt) |
Boyle's Law | British scientist Robert Boyle stated that the volume of a gas decreases when the pressure increases, provided the temperature stays the same (P: ^, T: -, V: v) |
buoyant force | ability of a fluid to exert an upward force on an object immersed in the fluid |
Charles's Law | French scientist Jacques Charles stated that the volume of a gas increases when temperature increases, provided pressure remains the same (P: -, V: ^, T: ^) |
chemical bond | the force that holds together the atoms in a compound; chemical bonding occurs because atoms of most elements become more stable by losing, gaining, and sharing electrons |
chemical change | the change of substances to different substances |
chemical formula | a precise statement that tells which elements are in a compound and their ratios |
chemical property | a characteristic of a substance that indicates whether it can undergo a specific chemical change |
chemical reaction | a change in which one or more substances are converted to differnet substances (the reactants are changed into the products) |
chemical symbol | a shorthand way to write the name of an element; for example: C for carbon, Ag for silver |
chemically stable | describes an atom whose outermost energy level is completely filled with electrons, thus rarely combines naturally with other elements |
chemically unstable | describes an atom whose outermost energy level is not filled with electrons so it seeks electrons from other atoms and thus forms compounds; for example: sodium, chlorine (salt) |
coagulation | process that destroys colloid structure; can be used to reduce a colloidal form of air pollution |
colloid | a heterogenus mixture containing tiny particles that never settle out; for example: milk, gelatin, smog |
compound | substance made of the combined atoms of two or more elements |
concentrated solution | a solution in which the amount of solute is near the maximumthe solvent can hold at that temperature |
concentration | generally, the proportion of a solute dissolved in a solvent |
condensation | the change of a substance from a gas to a liquid, which usually takes place when a gas is cooled to or below its boiling point |
condense | to go from the gas state to the liquid state, due to a loss of heat |