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Flashcards covering Vocabulary for all the topics in the notes
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Phase Changes
Changes of state from solid to liquid to gas that do not involve change in molecules, but a change in forces among molecules; examples include melting, evaporation/vaporization/boiling, sublimation, condensation, freezing/fusion, and deposition.
Intramolecular Forces
Chemical bonds (coulombic forces) that hold atoms together to form molecules through sharing electrons (covalent bonding), ionic bonding, or metallic bonding.
Intermolecular Forces
Forces that hold molecules (not atoms) together to form solids and liquids; include Dipole-Dipole forces, Hydrogen Bonding, and London Dispersion forces.
Dipole-Dipole Forces
Attraction between opposite partially charged ends of polar molecules; only 1% as strong as covalent or ionic bonds.
Hydrogen Bonding
Attraction between partially positively charged H atom attached to a highly electronegative atom (N, O, F) and a lone pair on another atom; a very strong dipole-dipole force.
London Dispersion Forces
Attraction between an instantaneous dipole and a dipole induced in a neighboring atom or particle; occurs in all atoms and molecules.
Polarizability
How easy the electron cloud can be distorted to produce temporary dipolar charge distribution; increases with the number of electrons.
Surface Tension
Resistance of a liquid to an increase in its surface area; increases with stronger intermolecular forces.
Capillary Action
Spontaneous rising of a liquid in a narrow tube involving adhesive and cohesive forces.
Viscosity
A liquid's resistance to flow; increases with larger intermolecular forces.
Vapor Pressure
Pressure exerted by a vapor; increases with temperature.
ΔH(vapor)
Energy required to vaporize 1 mole of a liquid at a pressure of 1 atm; also known as heat of vaporization or enthalpy of vaporization.
Equilibrium Vapor Pressure
Pressure of vapor present at equilibrium in a closed system.
Clausius-Clapeyron Equation
Relates vapor pressure and temperature; used to determine P(vap) at another temperature when ΔH(vap) and P(vap) at one temperature are known.
Heat of Fusion (ΔH(fus))
Enthalpy (energy) change that occurs at freezing point; endothermic.
Normal Melting Point
Temperature at which solid and liquid are at equilibrium with total pressure = 1 atm.
Normal Boiling Point
Temperature at which the vapor pressure of the liquid is exactly 1 atm.
Phase Diagram
Indicates phase at each temperature/pressure combination; lines represent phase transitions.
Triple Point
Temperature and pressure at which all three phases exist in a closed system (equilibrium).
Critical Point
Temperature and pressure at which gas and liquid are no longer different.
Solution
A homogenous mixture of a solute dissolved in a solvent.
Molarity (M)
Moles of solute per liter of solution.
Mass Percent
Percent by mass of the solute in the solution.
Mole Fraction (x)
Moles of a substance per total moles of mixture.
Molality (m)
Number of moles of solute per kilogram of solvent; does not change with temperature.
Enthalpy (Heat) of Hydration
Enthalpy change associated with the dispersal of a solute in water.
Henry's Law
Amount of gas dissolved is directly proportional to pressure of gas above solution (C = kP).
Colligative Property
Property of solutions that depends only on the amount of solute present, not its identity.
Raoult's Law
The vapor pressure of a solution is directly proportional to the mole fraction of solvent present.
Ideal Solutions
Solutions that obey Raoult's Law; Solute-solute, solvent-solvent, and solute-solvent interactions are similar.
Boiling Point Elevation
The increase in boiling point of a solvent due to the presence of a nonvolatile solute.
Freezing Point Depression
The decrease in freezing point of a solvent due to the presence of a solute.
Osmosis
Flow of solvent into a solution through a semipermeable membrane.
Osmotic Pressure (Pie)
The excess pressure on the solution that arises because of the difference in the liquid levels; Pie=MRT.
Isotonic Solutions
Solutions with identical osmotic pressures.
Van't Hoff Factor (i)
Number of particles a solute breaks into; i = moles of particles in solution / moles of solute dissolved.
Chemical Kinetics
The study of how fast a reaction proceeds.
Reaction Rate
Change in a concentration of a reactant or product per unit time; Molarity per second.
Rate Law
Expresses the rate of a reaction in terms of the concentrations of reactants; Rate=K[A]^m[B]^n.
Rate Constant (k)
A constant of proportionality between the reaction rate and the concentrations of reactants that appear in the rate law.
Differential Rate Law
Expresses how the rate depends on concentration.
Integrated Rate Law
Expresses how concentration depends on time.
Half-Life
Amount of time required for a reactant to reach half its original amount.
Reaction Mechanism
Series of elementary steps by which a chemical reaction occurs.
Elementary Step
Reaction whose rate law can be written from its molecularity.
Molecularity
Number of species that collide to produce reaction indicated by the step (Unimolecular, Bimolecular, Termolecular).
Intermediate
Species formed in an early step and consumed in a later step.
Catalyst
Species consumed in an early step and reformed in a later step; speeds up reaction.
Rate-Determining Step
The slowest step in a multistep reaction; determines rate law of reaction.
Activation Energy (Ea)
Minimum energy required to initiate chemical reaction.
Heterogeneous Catalysis
Catalyst is in a different phase than reactants.
Homogeneous Catalysis
Catalyst is in the same phase as reactants.
Chemical Equilibrium
State in which there are no observable changes as time goes by.
Law of Mass Action
Writing equilibrium constant expression.
Kc
Equilibrium constant based on concentration (M).
Kp
Equilibrium constant based on pressure (atm).
Equilibrium Position
Set of equilibrium concentrations; has infinite number of equilibrium positions.
Reaction Quotient, Q
Law of mass action using any concentrations instead of equilibrium concentrations.
Le Chatelier's Principle
If an external stress is applied to a system at equilibrium, the system adjusts in a way to reduce the stress and reach a new equilibrium.
Arrhenius Acid
Produces H+ in H2O.
Arrhenius Base
Produces OH- in H2O.
Bronsted-Lowry Acid
Proton (H+) donor.
Bronsted-Lowry Base
Proton (H+) acceptor.
Lewis Acid
Electron pair acceptor.
Lewis Base
Electron pair donor.
Autoionization of Water
The equilibrium constant for the reaction where a molecule of a substance ionizes by reacting with another molecule of the same substance; denoted as Kw.
Acid Ionization Constant (Ka)
Represents the fraction of the original acid that has been ionized in solution; value reflects the strength of acid.
Base Ionization Constant (Kb)
Equilibrium constant that measures how much a base ionizes in water; value indicates the strength of the base.
pH
Measure of acidity; pH range: Neutral Ph= 7, Basic pH>7, Acidic Ph<7.
Percent Dissociation
Percent of a weak acid that has dissociated into ions.
Polyprotic Acids
Acids that can produce more than one proton; dissociate in a stepwise manner.
Salts
Ionic compounds; cation is conjugate acid of a base, anion is conjugate base of acid.
Common Ion Effect
Shift in equilibrium position that occurs because of addition of ion already involved in equilibrium reaction; presence of common ion suppresses ionization of a weak acid or base.
Buffered Solution
Resists changes in pH with addition of either acid or bases; contains a weak acid or weak base and the conjugate.
Titration
Determine amount of acid or base in a solution; solution of known concentration (titrant) delivered from a buret into unknown solution (analyte) until substance being analyzed is just consumed.
Equivalence Point
Stoiciometric point where amount of titrant has been added to exactly react with all analyte originally present, signaled by color change of an indicator.
Solubility
Ability of a substance to dissolve; = x.
First Law of Thermodynamics
Energy can be converted from one form to another but cannot be created nor destroyed.
Second Law of Thermodynamics
The entropy of the UNIVERSE increases in spontaneous process and remains unchanged in an equilibirum process.
Third Law of Thermodynamics
The entropy of a perfect crystalline substance is zero at the absolute zero of temperature.
Entropy (S)
Measure of the randomness or disorder of a system; ΔS = Sf - Si.
Spontaneous process
Occurs without outside intervention, thermodynamically favored.
Gibbs Free Energy (ΔG)
Measure of spontaneity taking into account both enthalpy and entropy, at constant temperature and pressure and is negative for spontaneous processes, positive for nonspontaneous processes and zero at equilibrium.
Oxidation
Loss of electrons (OIL).
Reduction
Gain of electrons (RIG).
Reducing Agent
Electron donor; reactant that loses electrons (aka oxidized).
Oxidizing Agent
Electron acceptor; reactant gains electrons (aka reduced).
Cell Potential
Energy difference between half-reactions; also called electromotive force (emf).
Coordination Number
Number of bonds formed between metal ion and ligands in a complex ion.
Ligand
Neutral molecule or ion with lone electron pair (Lewis base) that can be used to form a bond with a metal ion.
Isomers
structural and stereoisomers (Optical, Geometric, Coordination, Linkage)