| Magma |
A molten mass of rock material within the earth |
| Magnetic Quantum Number |
The quantum number that is related to the orientation of the
orbitals in space |
| Main-group (representative) elements |
elements in the groups labeled I A, 2A, 3A, 4A, 5A, 6A, 7A,
and 8A in the periodic table The group number gives the sum of valence s and p electrons |
| Major species |
the components present in relatively large amounts in a
solution |
| Malleable |
Capable of being shaped by beating with a hammer or by
rolling |
| Manometer |
a device for measuring the pressure of a gas in a container |
| Mantle |
The largest portion of the earth, located between the core
and the crust |
| Mass |
the quantity of matter in an object |
| Mass defect |
the change in mass occurring when a nucleus is formed from
its component nucleons |
| Mass number |
the total number of protons and neutrons in the atomic
nucleus of an atom |
| Mass percent |
the percent by mass of a component of a mixture (11 1) or of
a given element in a compound |
| Mass spectrometer |
an instrument used to determine the relative masses of atoms
by the deflection of their ions in a magnetic field |
| Matter |
the material of the universe |
| Maximum Work |
The work done by a systern during a thermodynarnically
reversible change |
| Meniscus |
The curved surface of a liquid at the liquid-air interface in
a narrow tube |
| Messenger RNA (mRNA) |
a special RNA molecule built in the cell nucleus that
migrates into the cytoplasm and participates in protein synthesis |
| Metal |
an element that gives up electrons relatively easily and is
lustrous, malleable, and a good conductor of heat and electricity |
| Metallic Bond |
The electrostatic attraction binding the positive ions of a
solid metal together by means of a "sea" of delocalized valence electrons |
| Metalloenzyme |
an enzyme containing a metal ion at its active site |
| Metalloids (semimetals) |
elements along the division line in the periodic table
between metals and nonmetals These elements exhibit both metallic and nonmetallic
properties |
| Metallurgy |
The techniques employed in obtaining a metal from its ore and
preparing it for practical use |
| Metamorphic Rocks |
Rocks formed from other rocks-igneous, sedimentary, or
metamorphic-through the agency of extreme temperatures and pressures |
| Micelles |
aggregates of fatty acid anions having their hydrophobic
tails in the interior and their polar heads pointing outward to interact with the polar
water molecules |
| Minerals |
Substances present in the earth's crust having a uniform
composition and a definite crystalline structure |
| Miscible |
Capable of mixing in all proportions to form a homogeneous
mixture |
| Mixture |
a material of variable composition that contains two or more
substances |
| Model (theory) |
a set of assumptions put forth to explain the observed
behavior of matter. The models of chemistry usually involve assumptions about the behavior
of individual |
| Moderator |
a substance used in a nuclear reactor to slow down the
neutrons |
| Molal boiling-point elevation constant |
a constant characteristic of a particular solvent that gives
the change in boiling point as a function of solution molality; used in molecular weight
determinations |
| Molal freezing-point depression constant |
a constant characteristic of a particular solvent that gives
the change in freezing point as a function of the solution molality; used in motecular
weight determinations |
| Molality |
the number of moles of solute per kilogram of solvent in a
solution |
| Molar Absorptivity |
The proportionality constant in the Beer-Lambert law |
| Molar heat capacity |
the energy required to raise the temperature of one mole of a
substance by one degree Celsius |
| Molar mass |
the mass in grams of one mole of molecules or formula units
of a substance; also called molecular weight |
| Molar volume |
the volume of one mole of an ideal gas; equal to 22.42 liters
at STP |
| Molarity |
moles of solute per volume of solution in liters |
| Mole (mol) |
the number equal to the number of carbon atoms in exactly 12
grams of pure '2C: Avogadro's number One mole represents 6022 X 1023 units |
| Mole fraction |
the ratio of the number of moles of a given component in a
mixture to the total number of moles in the mixture |
| Mole ratio (stoichiometry) |
the ratio of moles of one substance to moles of another
substance in a balanced chemical equation |
| Molecular equation |
an equation representing a reaction in solution showing the
reactants and products in undissociated form, whether they are strong or weak electrolytes |
| Molecular formula |
the exact formula of a molecule, giving the types of atoms
and the number of each type |
| Molecular orbital (MO) model |
a model that regards a molecule as a collection of nuclei and
electrons, where the electrons are assumed to occupy orbitals much as they do in atoms,
but having the orbitals extend over the entire molecule In this model the electrons are
assumed to be delocalized rather than always located between a given pair of atoms |
| Molecular orientations (kinetics) |
orientations of molecules during collisions, some of which
can lead to reaction while others cannot |
| Molecular solid |
a solid composed of neutral molecules at the lattice points |
| Molecular structure |
the three-dimensional arrangement of atoms in a molecule |
| Molecular weight |
the mass in grams of one mole of molecules or formula units
of a substance; the same as molar mass |
| Molecularity |
the number of species that must collide to produce the
reaction represented by an elementary step in a reaction mechanism |
| Monochromatic |
Referring to radiant energy of a single wavelength |
| Monodentate Ligand |
a ligand that can form one bond to a metal ion |
| Monoprotic acid |
an acid with one acidic proton |
| Monosaccharide (simple sugar) |
a polyhydroxy ketone or aldehyde containing from three to
nine carbon atoms |
| Myoglobin |
an oxygen-storing biomolecule consisting of a heme complex
and a protein |
