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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

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