Vocabulary
Acid-dissociation
constant, (Ka): An equilibrium
constant that expresses the extent to which an acid transfers a proton to
solvent water.
Autoionization:
the process whereby water spontaneously forms low concentrations of H+
(aq) and OH- (aq) ions by proton transfer from one water molecule to
another.
Azimuthal
quantum number (l): The second quantum number which
denotes the shapes of the sublevels
Barometer:
a device used to measure atmospheric pressure.
Bronsted-Lowery
theory: an theory pertaining to acids and bases
where an acid is defined as a proton donor and a bases as a proton acceptor.
Calorimeter:
a device used to measure change in heat in a chemical reaction. There are
two types: coffee-cup and bomb calorimeters.
Catalyst:
a chemical that changes the rate of a chemical reaction but is not used during
the reaction. Generally used to speed up a reaction.
Chemical
bonding: the process by which atoms are combined to form
molecular elements and compounds.
Chemical
equilibrium: an ever changing state in a
reversible reaction where the rate of the forward reaction is equal to the rate
of the reverse reaction.
Colligative
properties: those properties of a solvent
(vapor-pressure lowering, freezing-point depression, boiling-pint elevation, and
osmotic pressure) that depend on the total concentration of solute particles
present.
Concentrated:
the state of a solution where the relative amounts of solute to solvent is high.
Conjugate
base: the product formed by loss of a proton
during the dissociation of acid.
Covalent
bonding: a type of chemical bonding characterized by the equal
sharing of one or more pairs of electrons between two atoms.
Dilute:
the state of a solution where the relative amounts of
solute to solvent is low.
Electrolytes:
ions
found in a solution that are capable of conducting electric current through the
solution.
Electron
affinity: the energy change that occurs when an
electron is added to a gaseous atom or ion.
Electron
configuration: a particular arrangement of
electrons in the orbitals of an atom.
Electron
dot notation: a notation which represents the
valence shell electrons of an atom or ion by arrangement around the symbol of
the particle.
Electronegativity:
a measurement of the ability of an atom to attract electrons in a chemical bond.
Endothermic:
a chemical reaction that absorbs heat. DH
is positive.
Energy:
the ability to do work.
Enthalpy
change (DH):
the heat absorbed or evolved during a reaction that occurs at constant pressure.
Equilibrium
constant: the ratio
of products to reactants, each concentration raised to the power corresponding
to the coefficient in the balanced equation.
Exothermic:
a chemical reaction that releases heat to the surroundings. DH
is negative.
First
law of thermodynamics: states that in any change
that occurs in nature, the total energy in the universe remains constant.
Energy cannot be created or destroyed.
Frequency:
the number of complete wavelengths (cycles) passing a given point per unit time
(cycles per second).
Hess’s
law: the heat evolved or absorbed in a chemical
process is the same whether the process takes place in one or in several steps.
Heterogeneous
equilibia
Hydrolysis:
the chemical reaction where a water molecule is added to another chemical.
Ideal
gas equation: a mathematical expression that
relates the volume, pressure, amount and temperature to each other. (PV = nRT)
Ionic
bonding: a chemical bond where there is a
transfer of electrons resulting in an electrostatic attraction between ions.
Ionization
energy: the amount of energy released when an
atom ionizes by losing one electron.
Water Dissociation
constant
(Kw): the product of the molar concentrations of
hydronium and hydroxide ions in pure water.
Kinetic
energy: the energy of
motion.
Kinetic
molecular theory:
the theory that a gas consists of molecules in constant random motion.
Lattice:
a repeated pattern of particles such s in a crystal.
Lattice
energy: the energy
required to break the lattice of a mole of an ionic compound.
Law
of conservation of energy:
energy cannot be created or destroyed.
LeChatlier’s
principle: if
a stress is applied to a system at equilibrium, the system shifts to minimize
the stress.
Lewis
structure: a
combination of Lewis symbols to represent a molecule or a polyatomic ion.
Shared electron pairs are drawn as dashes connecting atoms, and unshared
electron pairs are shown as dot pairs.
Lewis
theory: an acid-base
theory that defines acids as electron pair acceptors and bases as electron pair
donors.
Line
spectrum: a spectrum
which contains radiation of specific wavelengths and is observed as a patterns
of lines.
Magnetic
quantum number
(ml): the third quantum number which denotes
the orientation of an orbital in space relative to the other orbitals with the
same l and n values (orbitals of the same energy and shape).
Magnitude:
a numerical value of a vector without regard to direction.
Molality:
the concentration of a solution expressed as the number of moles of solute per
kg of solvent.
Molarity:
the concentration of a solution expressed as the
number of moles of solute in one liter of solution.
Mole
fraction: the ratio of
the number of moles of a component of a solution to the total number of moles of
all the components.
Net
ionic equation: an
ionic equation in which the spectator ions are omitted.
Normality:
the concentration of a solution expressed as the number
of equivalents of solute in one liter of solution.
Octet
rule
a rule specifying that with few exceptions,
the central atom in a molecule or a polyatomic ion tends to have eight electrons
on its valence shell.
Orbital:
a three-dimensional region around the nucleus in which the probability of
finding an electron is highest.
Orbital
notation: a
notation that shows the distribution and spin of the electrons around an atom.
Osmotic
pressure: the minimum
pressure required to prevent the
diffusion of a solvent through a semipermeable membrane.
pH
scale: a scale constructed using the -log[H3O+]
which denotes how acidic or basic a solution is. Values less than 7 are
acid and those above 7 and basic.
Photoelectric
effect: when
light shining on a clean metallic surface can cause the surface to emit
electrons.
Photon:
a quantum of radiant energy.
Polarity:
the extent in which a molecule possesses a dipole movement (partial positive
and partial negative ends).
Polyprotic:
an acid that can produce two or more moles of protons per mole of acid.
Potential
energy: stored
energy.
Pressure:
the force exerted per unit area caused the collisions of molecules.
Principle
quantum number:
the first quantum number that defines the energy and the size of the atomic
orbital.
Products:
a substance formed as a result of a reaction.
Quantity
of gas: the number of
moles of a gaseous compound or element.
Quantum:
the smallest quantity of radiant energy that can be absorbed or emitted by an
atom.
Quantum
numbers: an integer in
a set of integers that decribe the energy and other properties of an atomic
orbital. These are the solutions to the wave equation.
Radiant
energy: energy of
electromagnetic waves
propagated by simultaneous variations of electric and magnetic field
intensities.
Reactants;
a substance which undergoes chemical change.
Semipermeable
membrane; a membrane that allows passage of solvent
molecules such as water molecules, but not larger solute molecules.
Solute;
a substance dissolved in a solvent; usually the component of a smaller amount.
Solvent;
a substance which dissolves another substance; usually the component of a
solution present in the larger amount.
Specific
heat capacity;
the amount of heat required to raise the temperature of one gram of a substance
by one degree Celsius.
Spectrum;
an array of radiation arranged in the order of some varying characteristic such
as the wavelength.
Standard
atmosphere; 760mm
Hg, or in SI units, 101.325 kPa.
Standard
heats of formation;
the enthalpy change for the formation of one mole of a compound from its
elements.
Strong
acid; an acid that is completely
dissociated into ions in a dilute aqueous solution.
Subshell;
a subdivision within a shell of an atom designated by the quantum number l.
Temperature;
the property of an object that determines whether heat flows to it or away from
it spontaneously.
Uncertainty
principle; there
is an inherent uncertainty in the precision with which we can simultaneously
specify the location and momentum of a particle. It is of importance only
for the lightest particles such as the electron.
Valence
shell; the outermost shell
of an atom.
Volume;
the space occupied by an object or group of particles.
Wavelength;
the distance from a point in one wave to an equivalent point in the next wave.
Weak
acid; an acid that is only
slightly ionized in aqueous solution.
Weight
percentage; ratio between a mass of one component to the
total mass of all components.