http://www.ck12.org Chapter 27. Glossary
27.12 L
lanthanide
A series of 14 elements from cerium (atomic number 58) to lutetium (atomic number 71).
law of conservation of energy
A law that states that in any physical or chemical process, energy is neither created nor destroyed.
law of conservation of mass
A law that states that during a chemical reaction, the total mass of the products must be equal to the total mass
of the reactants.
law of definite proportions
A law that states that a given chemical compound always contains the same elements in the exact same
proportions by mass.
law of multiple proportions
A law that states that whenever the same two elements form more than one compound, the different masses of
one element that combine with the same mass of the other element are in the ratio of small whole numbers.
Le Châtelier’s principle
A chemical principle that states that when a chemical system that is at equilibrium is disturbed by a stress, the
system will respond in order to relieve the stress.
Lewis acid
A substance that accepts a pair of electrons to form a covalent bond.
Lewis base
A substance that donates a pair of electrons to form a covalent bond.
Lewis electron-dot structures
Notation that depicts valence electrons of an element as dots around the atomic symbol of that element; used
to depict the bonding patterns in molecules.
limiting reactant (reagent)
The reactant that is used up first in a reaction; the limiting reactant determines the amount of product that can
be formed in a chemical reaction.
lipid
A member of a class of water-insoluble compounds that includes oils, fats, and waxes.
liquid
A form of matter that has a definite volume, but an indefinite shape.
liter (L)
The volume of a cube that measures 10 cm (1 dm) on each side.
London dispersion forces
The intermolecular forces that occur between atoms and between nonpolar molecules as a result of the motion
of electrons.
lone pair
A pair of electrons in a Lewis electron-dot structure that is not shared between atoms.