Page 326 - Theory and Problems of BEGINNING CHEMISTRY

GLOSSARY 315

combustion reaction with oxygen gas.

completion complete consumption of at least one of the reactants in a chemical reaction. A reaction goes to
completion if its limiting quantity is used up.
compound a chemical combination of elements.
concentration the number of parts of solute in a given quantity of solution (molarity or normality) or of solvent
(molality).
condensed formula a formula for an organic compound that shows all bonds between atoms except those to
hydrogen atoms. The hydrogen atoms are placed to the right of the larger atoms to which they are attached.
conduct allow passage of electricity by movement of electrons in a wire or ions in a liquid.
+
conjugates an acid or base plus the product of reaction that differs by H .
control of electrons assignment for oxidation number purposes of the electrons in a covalent bond to the more
electronegative atom sharing them.
controlled experiment a series of individual experiments in which all factors except one are held constant so
that the effect of that factor on the outcome can be determined. Another series of experiments can be performed
for each additional factor to be tested.
covalent bonding bonding by shared electron pairs.

critical mass the smallest mass of a sample that will sustain a chain reaction. Smaller masses will lose neutrons
or other projectile particles from their bulk, and there will not be sufficient projectile particles to keep the chain
going.
current the flow of electrons or ions.
cycloalkane a hydrocarbon containing a ring of carbon atoms and only single bonds.
cycloalkene a hydrocarbon containing a ring of carbon atoms and one double bond per molecule.

Dalton’s law of partial pressures the total pressure of a mixture of gases is equal to the sum of the partial
pressures of the components.
Daniell cell a galvanic cell composed of copper/copper(II) ion and zinc/zinc ion half-cells.
daughter nucleus the large nucleus (as opposed to a small particle such as an alpha particle) that results from
the spontaneous disintegration of a (parent) nucleus.
decay radioactive disintegration.
decomposition reaction a reaction in which a compound decomposes to yield two substances.

definite proportions having the same ratio of masses of individual elements in every sample of the compound.
delocalized double bonds double bonds that are not permanently located between two specific atoms. The
electron pairs can be written equally well between one pair of atoms or another, as in benzene.

∆ Greek letter delta, meaning “change of.”
density mass divided by volume. A body of lower density will float in a liquid of higher density.
derivative a compound of a hydrocarbon with at least one hydrogen atom replaced by a functional group.
deuterium the isotope of hydrogen with a mass number of 2. Also called heavy hydrogen.
deuteron the nucleus of a deuterium atom.

diatomic composed of two atoms.
diffusion the passage of one gas through another.