Physical Science: Chemical Bonding, Intermolecular Forces, and Reaction Rates

Vocabulary flashcards covering nomenclature, bonding types, molecular polarity, intermolecular forces of attraction, and factors influencing the rate of chemical reactions.

Ion

An atom that has lost or gained electrons as it joins another atom to form molecules or compounds, thereby carrying an electric charge.

Cation

A positively charged ion that has more protons than electrons.

Anion

A negatively charged ion that has more electrons than protons.

Ionic Compound

A chemical compound composed of a metal and a nonmetal that forms through the transfer of electrons.

Covalent Compound

A molecular compound composed of two nonmetals that forms through the sharing of electrons.

Binary Acid

An acid composed of hydrogen and a single nonmetal element (containing no oxygen), named using the prefix hydro-, the root of the nonmetal, the suffix -ic, and the word acid.

Oxyacid

An acid containing hydrogen, oxygen, and a polyatomic oxyanion, named by replacing the anion suffix -ate with -ic acid or -ite with -ous acid without using the prefix hydro-.

Molecule

A group of two or more atoms held together by chemical bonds; the smallest identifiable unit of a pure substance that retains its original chemical and physical properties.

Polarity

The property of having a positive or negative end, also referred to as a dipole.

Polar Molecule

An asymmetrical molecule in which electrons are unequally shared between bonded atoms, creating partial positive and negative charges with dipoles that do not cancel out.

Nonpolar Molecule

A symmetrical molecule in which electrons are shared equally between bonded atoms, resulting in no charged ends because dipole moments cancel out to zero.

Electronegativity

The relative tendency of an atom to attract electrons to itself when chemically combined with another atom.

Nonpolar Covalent Bond

A covalent bond formed by the equal sharing of electrons, characterized by an electronegativity difference ($\Delta\text{EN}$) of $\le 0.4$.

Polar Covalent Bond

A covalent bond formed by the unequal sharing of electrons, characterized by an electronegativity difference ($\Delta\text{EN}$) of $0.5$ to $1.6$.

Ionic Bond

A bond involving the transfer of electrons between atoms, characterized by an electronegativity difference ($\Delta\text{EN}$) of $\ge 1.7$.

Solubility

The ability of a substance (solute) to dissolve in another substance (solvent).

Miscibility

The ability of two substances to mix together in all proportions.

Boiling Point

A physical property determined by molecular arrangement and polarity; higher polarity and stronger attractive forces result in a higher boiling point.

Surface Tension

The property of the surface of a liquid that allows it to resist an external force due to the cohesive nature of its molecules.

Evaporation

A phase change occurring at the surface of a liquid as it turns into a gas, which occurs more slowly in liquids with stronger intermolecular forces.

Viscosity

A measure of a fluid's resistance to flow, describing the internal friction within a moving fluid.

Capillary Action

The ability of a liquid to flow in narrow spaces without the assistance of, or even in opposition to, external forces like gravity.

Intermolecular Forces of Attraction

Attractive forces between neighboring molecules, collectively referred to as van der Waals forces, that are greatest in the solid state and weakest in the gas state.

London Dispersion Forces

The weakest category of intermolecular forces, present in nonpolar molecules, resulting from temporary shifts in electron density.

Dipole-Dipole Forces

Intermolecular forces between polar molecules that are stronger than London dispersion forces due to a permanent uneven distribution of electrons.

Hydrogen Bond

A special and strongest type of dipole-dipole attraction that occurs when a hydrogen atom is directly bonded to fluorine, oxygen, or nitrogen.

Chemical Reaction

A process in which reactants are transformed into new substances (products) through the breaking and forming of chemical bonds, resulting in a change in chemical identity.

Law of Conservation of Mass

A fundamental scientific law stating that the total mass of substances before a chemical reaction equals the total mass of substances after the reaction.

Reaction Rate

The speed at which reactants are converted into products during a chemical reaction.

Collision Theory

A theory stating that chemical reactions occur when reacting particles collide with sufficient energy and the proper orientation.

Concentration (in Chemical Reactions)

The amount of reactant particles present in a given volume; higher concentration results in more collisions and a faster reaction rate.

Surface Area (in Chemical Reactions)

The exposed portion of a reactant substance available for reaction; a greater surface area exposes more particles and increases the reaction rate.

Catalyst

A substance that speeds up a chemical reaction by lowering the activation energy without being consumed in the process.