# Chemistry exam vocab

## Terms

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the capacity for doing work or supplying heat
energy
enery that transfers from one object to another because of temperature difference between them
heat
defined as the quantity of heat needed to raise the temperature of one gram of pure water one degree Celcius
calorie
the SI unit of energy
joule
4.18 J
1 cal
the quatntity of heat required to change an objects temperature by exactly one degree Celsius
heat capacity
amount of heat it take to raise one gram of a substance one degree Celsius
specific heat capacity
a heat absorbic process
endothermic process
a heat dissipating process
exothermic process
the measurement of heat changes for physical and chemical processes
calorimetry
the tendency of molecules and ions to move toward areas of lower concentration until the concentration is uniform thoughout the system
diffusion
the pressure exerted by each gas in a gaseous mixture
partial pressure
factors of gases
Pressure (kPa, atm, mm Hg)
Temperature (K)
Volume (L, mL)
pressure and volume are inversely proportional in a gas, if temperature is kept constant
P1 x V1 = P2 x V2
Boyle's Law
temperature and volume are directly proportional, if pressure is kept constant
V1/T1 = V2/T2
Charles' Law
(P1 x V1)/T1 = (P2 x V2)/T2
Combined Gas Law
PV = nRT
(pressure x volume = # of moles x constant x temperature)
Ideal Gas Law
at a constant temperature and volume, total pressure exerted by a mix of gases is equal to the sum of partial pressures of the component gases
P1 + P2 + P3...= PT
Dalton's Law of Partial Pressure
equal volume of gases at the same temperature pressure contain equal numbers of particles
rate of effusion of gas is inversely proportional to the square root of its molar mass
Graham's Law
STP
Standard Temperature and Pressure
T= 0 degrees C
P= 101.3 kPa, 760 mm Hg, 1 atm
V= 22.4 L
1 nutritional Calorie
1000 calories
the height of a wave
amplitude
the pattern of frequencies obtained by passing light emited by atoms of an element in the gaseous state thorough a prism
the emission spectrum of each element is unique to that element
atomic emission spectrum
the arrangement of electrons around the nucleous of an atom in its ground state
electron configuration
a region around the nucleous of an atom where an electron is likely to be moving
energy level
a series of energy waves that travel in a vacuum at 3.0 10^10 cm/s
includes radio waves, microwaves, visible light, infrared and ultraviolet light, x-rays, and gamma rays
the lowest energy level occupied by an electron when an atom is in its most stable energy state
ground state
(v) the number of wave cycles that pass a given point per unit of time
frequency
the distance between two adjacent crests of a wave
wavelength
the SI unit of frequency, equal to one cycle per second
hertz
electrons are ejected by certain metals when they absorb light with a frequency above a threshold frequency
photoelectric effect
a quantum of light
a discrete bundle of electromagnetic energy that behaves as a particle
photon
the amount of energy needed to move an electron
quantum
half the distance between the nuclei in a molecule consisting of identical...
the tendency for an atom to attract electrons to itself when it is chemically combined with another element
electronegativity
the energy required to remove an electron from a gaseous atom
ionization energy
a vertical column of elements in the periodic table
the contituent elements of a group have similar chemical and physical properties
group
a horizontal row of elements in the periodic table
period
electrons enter orbitals of lowest energy first
lowest to highest
Aufbau principle
wave mechanics
wave like motions
de Broglie's equations
cannot know both velocity and position of particle (electron) at the same time
Heisenberg uncertainty principle
each orbital will get one electron before any orbital gets two
Hund's rule
two elecrons per orbital
now two electrons will have the same quantum number (NLMS)
Pauli exclusion principle
arranged by increasing atomic number
periodic repitition of physical and chemical properties
Periodic Law
Group IA
alkaline metals
Group IIA
alkaline earth metals
Group VIIA
halogens
Group VIIIA
noble gases
A Group
representative
B Group
transistion metals
lanthanide and actinide series
rare earth metals
(inner transition)
two different atoms joined by a convalent bond and the bonding electrons are shared unequally
polar
atoms in molecules are alike and bonding electrons are shared equally
nonpolar
angle at which adjacent atoms in a molecule are attracted
bond angle
a notation that depicts valence electrons as dots around the atomic structure of the element
the symbol represents inner electrons and atomic nucleus
electron dot structure
a process by which several atomic orbitals (such as s and p)mix to form the same number of equivalent hybrid orbitals
hybridization
atoms react by gaining or losing electrons as to acquire the stable electron structure of a noble gas, usually eight valence elctrons
octet rule
any atom or group of atoms with a negative charge
anion
any atom or group of atoms with a positive charge
cation
a molecule in which one or more atoms is slightly negative and one or more is slightly positive, unless molecular geometry causes the polarities to cancel each other out
polar molecule
a chemical formula that shows the arrangement of atoms in a molecule or polyatomic ion
each dash between two atoms indicates a pair of shared electrons
structural formula
a pair of valence electrons that is not involved in bonding
unshared pair
an electron in the highest occupied energy level of an atom
valence electrons
valence-shell electron-pair repulsion theory
because electron pairs repel, molecules adjust their shapes so that vealence-electron pairs are as far apart as possible
VSEPR theory
a term used to describe the weakest intermolecular attractions
these include dispersion forces and dipole interactions
van der Waals forces
the weakest kind of intermolecular attractions
this attraction is thought to be caused by the motion of electrons
dispersion force
a relatively strong intermolecular force in which a hydrogen atom that is covalently bonded to a very electronegative atom is also weakly bonded to an unshared electron pair of another electronegative atom in the same moleculr or one nearby
hydrogen bond
metal (cation) and nonmetal (anion) are bonded together
electrostatic attraction
ionic
two nonmetals are bonded together
share electrons
covalent
within metals
conducts electricity
metallic
an inward force that tends to minimize the surface area of a liquid
it causes the surface to behave as if it were a thin skin
surface tension
a suface active reagent
any sustance with molecules that interfere with the hydrogen bonding between water molecules, reducing surface tension
i.e. soaps and detergents
surfactants
(aq) a solution in which the solvent is water
aqueous solutions
the dissolving medium in a solution
solvent
dissolved particles in a solution
solute
a compound that conducts an electric current in aqueous solution or in the molten state
all ionic compounds are this
electrolyte
a compound that does not conduct an electric current in aqueous solution or in the molten state
nonelectrolyte
a mixture form which some of the particles settle out slowly upon standing
suspension
a mixture whose particles are intermediate in size between those of a susupension and a solute solution
colloid
scattering of light by particles in a colloid or suspension, which causes a beam of light to become visible
Tyndall effect
the chaotic movement of colloidal paricles caused by collision with particles of the solvent in which they are dispersed
Brownian motion
the colloidal dispersion of one liquid in another
emulsion
to lose water of hydration
the process occurs when the hydrate has a vapor pressure higher than that of water vapor in in the air
effloresce
a term describing salts and other compounds that remove moisture form the air
hygroscopic
a hygroscopic substance used as a drying agent
desiccant
a term describing a substance that removes sufficient water from the air to form a solution
the solution formed has a lower vapor pressure that that of the water in the air
deliquescent
a solution containing the maximum amount of solute for a given amount of solvent at a constant temperature and pressure
an equilibrium exists between undissolved solute and ions in solution
saturated solution
a solution that contains less solute than a saturated solution at a given temperature and pressure
unsaturated solution
describes liquids that dissolve in each other
miscible
describes liquids that are insoluble in one another
immiscible
at a given temperature, the solubility of a gas in a liquid is directly porportional to the pressure of the gas above the liquid
Henry's Law
a solution that contains more solute that it can theoretically hold and a given temperature
excess solute preciptates if a seed crystal is added
supersaturated solution
(M) the concentration of solute in a solution expressed as the number of moles of solute dissolved in one liter of solution
molarity
bond angle of water
105 degrees
at what temperature is water at maximum density
4 degrees C
? = moles of solute/liters of solution
Molarity
a compound that produces hydrogen ions in solution, is a hydrogen-ion donor, or an electron-pair acceptor
acid
a compound that produces hydroxide ions in solution, is a hydrogen-ion acceptor, or an electron-pair donor
base
a solution in which the pH remains relatively constant when small amounts of acid of base are added
can be either a solution of a weak acid and the salt of a weak acid or a solution of a weak base and the salt of a weak base
buffer
a number used to denote the hydrogen-ion concentration, or acidity, of a solution
it is the negative logarithm of the hydrogen-ion concentration of a solution
pH
(H3O+) the positive ion formed when a woter molecule hains a hydrogen ion
all the hydrogen ion in aqueous solution are present as this
hydronim ion
(OH-) the negative ion formed when a water molecule loses a hydrogen ion
hydroxide ion
method used to determine the concentration of a solution (often an acid or base)
a solution of known concentration (the standard)is added to a measured amount of the solution of unknown concentration until an indicator signals the end point
titration
an organic compound that contains only carbon and hydrogen
hydrocarbon
the controlled process by which hydrocarbons are broken down or rearranged into smaller, more useful molecules
cracking
a very large molecule formed by the covalent bonding of repeating small molecules, known as monomers
polymers
a simple molecule that repeatedly combines to form a polymer
monomer
an organic compound having and -OH (hydroxyl)group
the general structure is R-OH
alocohol
an organic compound having amino (-NH2) and carboxylic (-COOH) groups in the same molecule
amino acid
a name originally given to the arenes because many of them have pleasant odors
any compound with bonding like that of benzene
aromatic compound
the name given to monomers and polymers of aldehydes and ketones that have numerous hydroxyl groups
i.e.sugars and starches
carbohydrates
proteins that act as catalyst
enzyme
a member of a large class of relatively water-insoluble organic compounds
i.e. fats, oils, waxes
lipids
a polymer of RNA or DNA found primarily in cell nuclei
play an important role in the transmission of hereditary characteristics, protein syntheis, and the control of cell activities
nucleic acid
one of the monomers that make up DNA and RNA
it consists of a nitrogen-containing base, a sugar, and a phosphate group
nucleotide
any peptide with more than 100 amino acids
protein
the process used to make soap
in involves the hydrolysis of fats or oils by a hot aqueous alikli-metal hydroxide
saponification
an organic compound in which all carbon atoms are joined by single covalent bonds
it contains the maximum number of hydrogen atoms
saturated compounds
an organic compound with one or more double or triple carbon-carbon bonds
unsaturated compounds
functional group for organic acids
COOH
functional group for alcohols
OH

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