Understanding Core Chemistry Terms

Fundamental Chemistry Definitions

Chemical Bond

The force that holds two or more atoms together to form a compound.

Litmus Paper

Paper strips containing litmus, available in both blue and red, used to indicate pH.

Ionic Compound

A compound formed from oppositely charged ions.

Hydronium Ions

Ions (H₃O⁺) that form when a hydrogen ion (H⁺) separates from an acid and bonds with a water molecule (H₂O).

Hydroxide Ion

Ions (OH⁻) that form when a base dissolves in water and dissociates.

Brittleness

The tendency of ionic compounds to be brittle solids at room temperature, causing them to break apart easily when struck.

Corrosive

A property of a substance that causes destruction or damage upon contact with other materials.

Melting Point

The temperature at which a solid changes state to a liquid at a given atmospheric pressure.

Solubility

The maximum amount of a substance that can dissolve in a unit volume of a liquid, known as the solvent, at a specific temperature.

Electrical Conductivity

The measure of a material's ability to conduct electrical current.

Covalent Compound

A chemical compound formed by the sharing of valence electrons between atoms.

Acid

Any compound that increases the concentration of hydronium ions (H₃O⁺) when dissolved in water.

Base

Any compound that increases the concentration of hydroxide ions (OH⁻) when dissolved in water.

Molecule

The smallest particle into which a covalently bonded compound can be divided while retaining the chemical properties of that compound.

Indicator

A compound that changes color depending on the pH value of a solution.

Strong Acid

An acid that completely dissociates (breaks apart) into ions when dissolved in water.

Weak Acid

An acid that only partially dissociates into ions when dissolved in water.

Strong Base

A base whose molecules completely dissociate in water to produce hydroxide ions (OH⁻).

Weak Base

A base whose molecules only partially dissociate in water.

Neutralization Reaction

The chemical reaction between an acid and a base, producing water and a salt.

Specific Heat

The quantity of heat required to raise the temperature of a unit mass of a homogeneous material by one degree Celsius (or Kelvin) at a given constant pressure.

pH Scale

A numerical scale (0-14) used to express the acidity or basicity of an aqueous solution.

Salt (Chemical)

An ionic compound formed from the reaction of an acid and a base, typically consisting of a metal cation and a nonmetal anion.