Thou shalt not forget.docx

Coulombic attraction

The force of attraction between charged particles, such as electrons and the nucleus.

 Z_eff

Effective nuclear charge, the net positive charge experienced by an electron in an atom.

PES graph

Photoelectron spectroscopy graph, a graph that shows the energy levels and number of electrons in different sublevels of an atom.

Electron configuration

The arrangement of electrons in an atom or ion.

Isotopes

Atoms of the same element that have different numbers of neutrons.

Mass spectroscopy

A technique used to measure the atomic masses of isotopes.

Group

A vertical column on the periodic table, elements in the same group have similar chemical and physical properties.

Metals

Elements located on the left side of the periodic table, typically have metallic properties.

Nonmetals

Elements located on the right side of the periodic table, typically have nonmetallic properties.

Cations

Positively charged ions, formed by removing electrons from atoms.

Anions

Negatively charged ions, formed by adding electrons to atoms.

Covalent bonds

Bonds formed by the sharing of electrons between two nonmetals.

Ionic bonds

Bonds formed by the transfer of electrons from a metal to a nonmetal.

Electronegativity

The ability of an atom to attract electrons in a chemical bond.

Combustion reactions

Reactions that involve the burning of a substance to produce carbon dioxide and water.

Bond angles

The angles between the bonds in a molecule.

Lattice energy

The energy required to break an ionic bond in a compound.

Formal charge

A calculation used to determine the distribution of electrons in a Lewis structure.

Octet rule

The tendency of atoms to gain, lose, or share electrons to achieve a stable electron configuration with eight valence electrons.

Metallic bonds

Bonds formed between metal atoms, characterized by the delocalization of electrons.

Intermolecular forces

Forces of attraction between molecules.

London Dispersion forces

The weakest intermolecular force, caused by temporary fluctuations in electron distribution.

Dipole-dipole forces

Intermolecular forces between polar molecules, caused by the attraction between positive and negative ends of the molecules.

Hydrogen bonding

A strong type of dipole-dipole force that occurs when hydrogen is bonded to a highly electronegative atom.

Ion-dipole forces

Forces of attraction between ions and polar molecules.

Boiling point

The temperature at which a substance changes from a liquid to a gas.

Melting point

The temperature at which a substance changes from a solid to a liquid.

Molecular solids

Solids composed of individual molecules held together by intermolecular forces.

Ionic solids

Solids composed of ions held together by ionic bonds.

Covalent network solids

Solids in which the atoms are bonded together in a continuous network.

Gas mixtures

Homogeneous mixtures of gases.

Compressible

The ability of a substance to be squeezed into a smaller volume.

Gas pressure

The force exerted by gas particles on the walls of a container.

Boyle's Law

The relationship between the pressure and volume of a gas, when temperature is held constant.

Charles's Law

The relationship between the volume and temperature of a gas, when pressure is held constant.

Gay-Lussac's Law

The relationship between the pressure and temperature of a gas, when volume is held constant.

Ideal gas law

The equation that relates the pressure, volume, temperature, and number of moles of a gas.

Molar mass

The mass of one mole of a substance.

Average kinetic energy

The average energy of motion of particles in a substance.

Water displacement

A method used to collect gases by displacing water in a container.

Real gases

Gases that do not behave exactly like an ideal gas due to intermolecular forces and molecular size.

Solutions

Homogeneous mixtures of two or more substances.

Mixtures

Combinations of two or more substances that are not chemically combined.

Filtering

A method used to separate mixtures based on differences in particle size.

Distillation

A method used to separate mixtures based on differences in boiling point.

Chromatography

A method used to separate mixtures based on differences in polarity.

Density

The mass per unit volume of a substance.

% composition

The percentage of each element in a compound by mass.

M1V1 = M2V2

A formula used for dilution calculations in chemistry.

Meniscus

The curved surface of a liquid in a container, used for reading the volume of a liquid.

Sig

Significant figures, the digits in a number that carry meaningful information.

Graduated cylinder

A measuring device used to measure the volume of liquids.

Volumetric flask

A measuring device with a single line to measure a specific volume of liquid.

Empirical formula

The simplest whole number ratio of atoms in a compound.

Molecular formula

The actual number of atoms of each element in a compound.

% yield

The percentage of the theoretical yield that is actually obtained in a chemical reaction.

% error

The percentage difference between the experimental and theoretical values in a measurement or calculation.

Limiting reactant

The reactant that is completely consumed in a chemical reaction and determines the amount of product formed.

Activation energy

The minimum energy required for a chemical reaction to occur.

Rate law

An equation that relates the rate of a chemical reaction to the concentrations of reactants.

Rate constant

A proportionality constant in the rate law equation.

Catalyst

A substance that increases the rate of a chemical reaction by lowering the activation energy.

Half-life

The time it takes for the concentration of a reactant to decrease by half in a first-order reaction.

Exothermic reaction

A reaction that releases heat to the surroundings.

Endothermic reaction

A reaction that absorbs heat from the surroundings.

ΔHrxn

The change in enthalpy of a reaction.

Equilibrium constant (Keq)

The ratio of the concentrations of products to reactants at equilibrium.

Le Chatelier's Principle

When a system at equilibrium is disturbed, it will shift to counteract the disturbance.

Molar solubility

The concentration of a solute in a saturated solution at equilibrium.

pH

A measure of the acidity or alkalinity of a solution.

Hydronium ion

H3O+, the ion formed when an acid donates a proton.

Strong base

A base that completely ionizes in water.

Conjugate base

The species that remains after an acid has donated a proton.

Acid-Base reaction

A chemical reaction between an acid and a base, resulting in the formation of a salt and water.

[H+]

The concentration of hydrogen ions in a solution.

[OH-]

The concentration of hydroxide ions in a solution.

% Ionization

The percentage of a weak acid or weak base that dissociates into ions in a solution.

Conjugate Base

The ion formed when an acid loses a hydrogen ion.

Conjugate Acid

The ion formed when a base gains a hydrogen ion.

Neutral Salt

A salt that does not affect the pH of a solution.

Ka Value

The acid dissociation constant, which indicates the strength of an acid.

Kb Value

The base dissociation constant, which indicates the strength of a base.

Titrations

A technique used to determine the concentration of a substance in a solution by reacting it with a known concentration of another substance.

Buffers

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

Equivalence Point

The point in a titration where the moles of acid and base are stoichiometrically equivalent.

Thermodynamically Favorable

Reactions that occur spontaneously and have a negative change in Gibbs free energy (ΔG).

ΔH

The change in enthalpy, which represents the heat absorbed or released during a reaction.

ΔS

The change in entropy, which represents the degree of disorder in a system.

Keq

The equilibrium constant, which indicates the ratio of products to reactants at equilibrium.

Activation Energy

The energy barrier that must be overcome for a reaction to occur.

Oxidation Numbers

Numbers assigned to atoms in a compound to indicate the distribution of electrons.

Anode

The electrode where oxidation occurs in both a battery and an electrolytic cell.

Cathode

The electrode where reduction occurs in both a battery and an electrolytic cell.

Salt Bridge

A pathway for the flow of ions between the two half-cells in an electrochemical cell.

Eo Cell

The standard cell potential, which indicates the voltage of a battery or electrolytic cell.

Half-Reaction

The individual oxidation or reduction reaction that occurs in an electrochemical cell.

ΔGo

The change in Gibbs free energy at standard conditions.

Electroplating

The process of depositing a layer of metal onto a surface using an electric current.