Chemistry Units 10-21 Overview

Vocabulary terms covering Intermolecular Forces, Kinetics, Equilibrium, Acids/Bases, Thermodynamics, Electrochemistry, and Nuclear Chemistry as outlined in the Unit 10-21 checklist.

London Dispersion Forces

The weakest intermolecular force, present in all molecules, resulting from temporary shifts in electron density.

Dipole-Dipole Forces

Intermolecular forces that occur between the positive end of one polar molecule and the negative end of another.

Hydrogen Bonding

A specific, strong type of dipole-dipole interaction occurring when hydrogen is covalently bonded to highly electronegative atoms like N, O, or F.

Ion-Dipole Forces

The force of attraction between an ion and a polar molecule.

Viscosity

A measure of a liquid's resistance to flow.

Surface Tension

The energy required to increase the surface area of a liquid due to intermolecular forces.

Vapor Pressure

The pressure exerted by a vapor when it is in equilibrium with its liquid phase at a given temperature.

Volatility

The tendency of a substance to evaporate or vaporize at normal temperatures.

Triple Point

The specific temperature and pressure at which the solid, liquid, and gaseous phases of a substance coexist in equilibrium.

Critical Point

The temperature and pressure above which the distinction between liquid and gas disappears, forming a supercritical fluid.

Electrolytes

Substances that dissolve in water to produce ions and conduct electricity; classified as strong or weak based on degree of dissociation.

Like Dissolves Like

A general rule for solubility stating that polar solvents dissolve polar solutes, and nonpolar solvents dissolve nonpolar solutes.

Colligative Properties

Properties of a solution, such as boiling point elevation and freezing point depression, that depend only on the number of solute particles, not their identity.

Osmotic Pressure

The pressure required to stop the flow of solvent across a semipermeable membrane.

Van’t Hoff Factor

A value represented by the symbol $i$ that accounts for the number of particles a solute forms in solution during colligative property calculations.

Activation Energy

The minimum amount of energy required to initiate a chemical reaction, often denoted as $E_a$.

Collision Theory

The theory that chemical reactions occur when particles collide with sufficient energy and correct orientation.

Catalysis

The process of increasing the rate of a chemical reaction by adding a substance (a catalyst) that provides an alternative pathway with a lower activation energy.

Le Châtelier’s Principle

States that if a system at equilibrium is disturbed by a change in temperature, pressure, or concentration, the system will shift its equilibrium position to counteract the disturbance.

ICE Table

A tool used to calculate equilibrium concentrations or pressures by tracking Initial values, Changes, and Equilibrium states.

Brønsted-Lowry Acid

A substance that acts as a proton ($H^+$) donor.

Brønsted-Lowry Base

A substance that acts as a proton ($H^+$) acceptor.

Polyprotic Acids

Acids capable of losing more than one proton per molecule in stepwise ionizations.

Buffers

Solutions consisting of a weak acid and its conjugate base that resist significant changes in pH when small amounts of acid or base are added.

Henderson-Hasselbalch Equation

An equation used to calculate the pH of a buffer solution: pH = pK_a + ext{log}rac{[ ext{Base}]}{[ ext{Acid}]}.

Solubility Product Constant

Represented as $K_{sp}$, the equilibrium constant for the dissolution of a sparingly soluble ionic compound in water.

Lewis Acid

An atom, ion, or molecule that accepts an electron pair.

Lewis Base

An atom, ion, or molecule that donates an electron pair.

Entropy

Represented as $S$, a thermodynamic property that measures the degree of disorder or randomness in a system.

Gibbs Free Energy

Represented as $G$, a thermodynamic potential used to predict the spontaneity of a process: $riangle G = riangle H - T riangle S$.

Anode

The electrode in an electrochemical cell where oxidation occurs and electrons are lost.

Cathode

The electrode in an electrochemical cell where reduction occurs and electrons are gained.

Nernst Equation

An equation used to calculate cell potentials under non-standard conditions based on the standard potential, temperature, and reaction quotient $Q$.

Alpha Decay

A type of radioactive decay in which an atomic nucleus emits an alpha particle (a helium nucleus consisting of two protons and two neutrons).

Beta Decay

Radioactive decay involving the emission of a beta particle (an electron or a positron) from an atomic nucleus.

Gamma Decay

The emission of high-energy electromagnetic radiation (gamma rays) from an excited nucleus.