AP Chemistry Part B Flashcards

Reaction Rate

Change in concentration of reactants/products over time.

Rate Laws

Expressed as Rate = k[A]^m[B]^n; determined experimentally.

Order of Reaction

Exponents (m and n) in the rate law that are not necessarily stoichiometric coefficients.

Integrated Rate Laws

Mathematical expressions that relate concentration of reactants/products to time.

Catalysts

Substances that lower activation energy and increase reaction rate without being consumed.

Enthalpy (ΔH)

Heat content of a system at constant pressure.

Endothermic

Processes that absorb heat, resulting in ΔH > 0.

Exothermic

Processes that release heat, resulting in ΔH < 0.

Calorimetry

The measurement of heat flow in processes.

Hess's Law

States that the total enthalpy change for a reaction is the sum of the enthalpy changes for the individual steps.

Entropy (S)

Measure of disorder; tends to increase in spontaneous processes.

Second Law of Thermodynamics

States that the total entropy of the universe increases for spontaneous processes.

Gibbs Free Energy (ΔG)

A thermodynamic potential that can predict the spontaneity of a process.

Dynamic Equilibrium

Condition where the rate of the forward reaction equals the rate of the reverse reaction.

Law of Mass Action

Expression describing the relationship between the concentrations of reactants and products in a reaction at equilibrium.

Equilibrium Constants (K)

Ratio of concentrations of products to reactants at equilibrium.

Le Chatelier’s Principle

States that if a stress is applied to a system in equilibrium, the system shifts to counteract the stress.

Solubility Product Constant (Ksp)

Product of the concentrations of the ions in a saturated solution.

Common Ion Effect

Decreased solubility of a salt in a solution that already contains one of its constituent ions.

Arrhenius Acids and Bases

Acids produce H⁺ ions and bases produce OH⁻ ions in aqueous solution.

Brønsted-Lowry Acids and Bases

Acids donate H⁺; bases accept H⁺.

Lewis Acids and Bases

Acids accept electron pairs; bases donate electron pairs.

Buffer Solutions

Solutions that resist changes in pH when small amounts of acid or base are added.

Titration

Technique used to determine the concentration of an unknown solution by reacting it with a solution of known concentration.

Redox Reactions

Reactions that involve the transfer of electrons between species.

Galvanic Cells

Devices that convert chemical energy into electrical energy through spontaneous redox reactions.

Cell Potential (E°cell)

The voltage potential of a galvanic cell, calculated from the reduction potentials of its half-cells.

Nernst Equation

Equation used to calculate the cell potential under nonstandard conditions.

Alkanes

Hydrocarbons with single carbon-carbon bonds (saturated).

Alkenes

Hydrocarbons with at least one double bond (unsaturated).

Alkynes

Hydrocarbons with at least one triple bond.

Aromatic Compounds

Compounds containing benzene rings with delocalized π electrons.

Functional Groups

Specific groups of atoms within molecules that determine the characteristic chemical reactions of those molecules.

Addition Polymers

Polymers formed by the addition of unsaturated monomers.

Condensation Polymers

Polymers formed through the reaction of monomers with the loss of a small molecule like water.

Activation Energy

Energy required to initiate a chemical reaction.

Differential Rate Law

A mathematical expression showing how the rate of reaction depends on the concentration of reactants.

First-Order Reaction

A graph of ln[reactant] vs. time yields a straight line. Rate is proportional to concentration.

Catalyst

A substance that speeds up a reaction without being consumed in the process.

Thermodynamics

The study of energy and its transformations.

State Function

A function that depends only on the initial and final states of the system, not on the path.

Internal Energy (ΔE)

The heat released or absorbed at constant volume.

Third Law of Thermodynamics

Absolute zero; all molecular motion ceases.

Standard Free Energy of Formation (ΔG°f)

The standard free-energy change for the formation of 1 mole of a compound from its elements in their standard states.

Chemical Equilibrium

The state where the rates of the forward and reverse reactions are equal, and the net change in concentrations of reactants and products is zero.

Equilibrium Expression

The ratio of products to reactants at equilibrium, each raised to their stoichiometric coefficients.

Strong Acid

An acid that dissociates completely in water.

Strong Base

A base that dissociates completely in water.

pKa

The negative logarithm of the acid dissociation constant (Ka).

Electrochemistry

The study of chemical reactions that produce electricity and the changes caused by the passage of electricity through matter.

Anode

An electrode where oxidation occurs.

Cathode

An electrode where reduction occurs.

Cell Diagram

A shorthand notation representing the reactions in an electrochemical cell.

Hydrocarbons

Compounds containing only carbon and hydrogen.

Structural Isomers

Isomers that differ in the order in which the atoms are connected.