AP Chemistry Comprehensive Lecture Review

Vocabulary-based flashcards covering Atomic Structure, Molecular Properties, Intermolecular Forces, Kinetics, Thermodynamics, Equilibrium, and Electrochemistry based on the lecture transcript.

Isotopes

Atoms of an element with different numbers of neutrons.

Average atomic mass

The weighted average calculated from the isotope mass and relative abundance (frequency) of an element.

Avogadro’s number

$6.022 \times 10^{23}$.

Conditions at STP

$1\,atm$ and $273\,K$, where the molar volume of a gas is $22.4\,L/mol$.

Molarity (M)

A measurement of concentration defined as $M = \text{moles/L}$.

Coulomb’s law

$F = \frac{kq_1q_2}{r^2}$, where $F$ is the electrostatic force.

Photoelectron Spectroscopy (PES) Energy Equation

$\text{Incoming radiation energy} = \text{binding energy} + \text{kinetic energy of the ejected electron}$.

Aufbau principle

Electron configuration rule stating that electrons fill the lowest energy subshells available first.

Pauli exclusion principle

Rule stating that two electrons in the same orbital cannot have the same spin.

Hund’s rule

Rule stating that electrons occupy empty subshells first before pairing up.

Ionization energy

The energy required to remove an electron from an atom.

Electronegativity

How strongly the nucleus of an atom attracts electrons of other atoms in a bond.

Electron affinity

The energy change that occurs when an electron is added to an atom in the gas state, which is usually exothermic.

Shielding

A phenomenon where electrons between the valence electrons and the nucleus cause the valence electrons to be less attracted to the nucleus.

Ionic Solid Conductivity

Ionic solids are poor conductors because electrons do not move around the lattice; however, ionic liquids conduct because ions are free to move.

Sea of electrons model

A metallic bonding model where a positively charged core remains stationary while valence electrons are highly mobile.

Interstitial alloy

An alloy formed with metals of different radii.

Substitutional alloy

An alloy formed with metals of similar radii.

Sigma (\sigma) and Pi (\pi) Bonds

A single bond has one sigma bond; a double bond has one sigma and one pi bond; a triple bond has one sigma and two pi bonds.

Resonance

A condition used in bond order calculations where all possible orders of a specific bond are averaged together.

Formal charge

$\text{number of valence electrons} - \text{assigned electrons}$, where assigned electrons include one electron for each line shared in a bond.

Dipole-dipole forces

Intermolecular forces in polar molecules where the positive end of one molecule is attracted to the negative end of another.

Hydrogen bonds

A strong type of dipole-dipole attraction occurring when a positively charged hydrogen atom is attracted to an extremely electronegative element ($F$, $O$, or $N$).

London dispersion forces (LDF)

Weak attractions present in all molecules due to the random motion of electrons which creates instantaneous polarity.

Vaporization

A phase transition from liquid to gas that occurs without adding outside energy, dependent on the speed of molecules hitting the liquid surface.

Retention factor (Rf)

$Rf = \frac{\text{distance traveled by solute}}{\text{distance traveled by solvent front}}$.

Effusion

The rate at which a gas escapes from a container through microscopic holes, moving from high to low pressure.

Beer’s law

$A = abc$, where $A$ is absorbance, $a$ is molar absorptivity, $b$ is path length, and $c$ is concentration.

Reaction Quotient (Q)

Calculating the ratio of products to reactants at any point in time using current concentrations or pressures.

Common ion effect

The shift in equilibrium that occurs when an ion already present in the equilibrium transition is added from a separate solution.

Amphoteric

A substance, such as water, that is capable of acting as either an acid or a base.

Rate determining step

The slowest step in a reaction mechanism that determines the overall speed of the reaction.

Intermediate

A species produced in one step of a reaction mechanism but fully consumed in a later step, so it does not appear in the balanced equation.

Catalyst

A substance that increases reaction rate by entering the mechanism first and exiting last without being consumed.

Enthalpy of formation (\Delta H_f)

The change in energy when one mole of a compound is formed from its component pure elements under standard conditions.

Specific heat

The amount of heat required to raise the temperature of one gram of a substance by one degree $C/K$.

Equivalence point

The point in a titration where just enough base has been added to neutralize all of the acid initially present.

Entropy (S)

A measure of the randomness or dispersion of a system.

Gibbs Free Energy Equation

$\Delta G = \Delta H - T \Delta S$.

Salt Bridge

A component in a galvanic cell that maintains electrical neutrality by allowing cations to flow to the cathode and anions to the anode.

Electrolytic cell

A cell that uses an outside source of voltage to force a non-spontaneous (unfavored) redox reaction to occur.