| Kelvin Temperature Scale |
An absolute temperature scale with 0 K at absolute zero
and 273 K at the freezing point of water |
| Kinetic Energy |
The energy of a mass resulting from its motion An object of
mass m moving with a velocity v has kinetic energy / mv |
| Kinetic molecular theory |
a model that assumes that an ideal gas is composed of tiny
particles (molecules) in constant motion |
| Lanthanides |
a group of fourteen elements following lanthanurn in the
periodic table, in which the 4f orbitals are being filled |
| Lanthanide Contraction |
The gradual decrease in atomic size of the inner transition
elements following lanthanum in the periodic table f block |
| Latent Image |
The invisible pattern formed on a photographic film by
exposure to light |
| Lattice |
a three-dimensional system of points designating the
positions of the centers of the components of a solid (atoms, ions, or molecules) |
| Lattice energy |
the energy change occurring when separated gaseous ions are
packed together to form an ionic solid |
| Law of conservation of energy |
energy can be converted from one form to another but can be
neither created nor destroyed |
| Law of conservation of mass |
mass is neither created nor destroyed |
| Law of Constant Composition |
A substance always contains the same elements, in the same
ratio by mass |
| Law of definite proportions |
a given compound always contains exactly the same proportion
of elements by mass |
| Law of mass action |
a general description of the equilibrium condition; it
defines the equilibrium constant expression |
| Law of multiple proportions |
When two elements form more than one compound, the masses of
one element combining with a fixed mass of the other are in the ratio of small whole
numbers |
| Leaching |
the extraction of metals from ores using aqueous chemical
solutions |
| Lead storage battery |
a battery (used in cars) in which the anode is lead, the
cathode is lead coated with lead dioxide, and the electrolyte is a sulfuric acid solution |
| Le Chatelier's principle |
if a change is imposed on a system at equilibrium, the
position of the equilibrium will shift in a direction that tends to reduce the effect of
that change |
| Levorotatory |
Having the ability to rotate the plane of vibration of
plane-polarized light to the left |
| Lewis Acid |
A substance capable of accepting an electron pair |
| Lewis Base |
A substance capable of donating an electron pair |
| Lewis Structure |
The representation of the electron arrangement in atoms,
ions, or molecules by showing the valence electrons as dots placed around the symbols for
the elements |
| Ligand |
A Lewis base coordinated with a metal atom or ion to form a
coordination complex |
| Ligand Field Theory |
A molecular-orbital bonding model for the electron structure
of coordination complexes |
| Limiting reactant |
the reactant that is completely consumed when a reaction is
run to completion |
| Line spectrum |
a spectrum showing only certain discrete wavelengths |
| Linear Accelerator |
A device for accelerating ions along a straight-line path for
use in nuclear reactions |
| Linkage isomerism |
isomerism involving a complex ion where the ligands are all
the same but the point of attachment of at least one of the ligands differs |
| Lipids |
water-insoluble substances that can be extracted from cells
by nonpolar organic solvents |
| Liquefaction |
the transformation of a gas into a liquid |
| Liquid Crystal |
A condition in which a substance possesses the flow
properties of a liquid and, to a degree, the molecular order of a crystalline solid |
| Localized electron (LE) model |
a model which assumes that a molecule is composed of atoms
that are bound together by sharing pairs of electrons using the atomic orbitals of the
bound atoms |
| Lock-and-key model |
a model for the mechanism of enzyme activity postulating that
the shapes of the substrate and the enzyme are such that they fit together as a key fits a
specific lock |
| London Forces |
Weak intermolecular attractions resulting from momentarily
induced dipoles |
| Lone pair |
an electron pair that is localized on a given atom; an
electron pair not involved in bonding |
