Acids and bases (A-level only) key terms

Brønsted-Lowry acid

A substance that donates protons (H+) in a chemical reaction.

Brønsted-Lowry base

A substance that accepts protons (H+) in a chemical reaction.

Conjugate acid

The species formed when a Brønsted-Lowry base gains a proton.

Conjugate base

The species formed when a Brønsted-Lowry acid loses a proton.

Proton Transfer

The process of transferring a proton (H+) from one species to another in a chemical reaction.

Equilibrium Constant (Kc)

A numerical value that expresses the ratio of the concentrations of products to reactants at equilibrium for a reversible reaction.

Acid Strength

The ability of an acid to donate protons (H+) to a base, determined by the extent of dissociation in solution.

Acid Concentration

The amount of acid present in a given volume of solution, typically expressed in mol/dm³.

Hydrogen ion concentration

The amount of hydrogen ions present in a solution, typically expressed in mol/dm³.

pH scale

A logarithmic scale used to specify the acidity or basicity of an aqueous solution, ranging from 0 (very acidic) to 14 (very basic).

Acid

A substance that donates hydrogen ions (H⁺) in a solution.

Base

A substance that accepts hydrogen ions (H⁺) or donates hydroxide ions (OH⁻) in a solution.

pH

A measure of the acidity or basicity of a solution, calculated as the negative logarithm of the hydrogen ion concentration.

Kw

The ion product of water, equal to 1.0 x 10^-14 at 25°C, representing the equilibrium constant for the self-ionization of water.

Strong Acid

An acid that completely dissociates in solution, releasing all its hydrogen ions.

Strong Base

A base that completely dissociates in solution, releasing all its hydroxide ions.

Weak Acid

An acid that partially dissociates in solution, establishing an equilibrium between the undissociated acid and its ions.

Acid Dissociation Constant (Ka)

A quantitative measure of the strength of an acid in solution, represented by the equilibrium constant for the dissociation reaction.

Weak acid

An acid that partially dissociates in solution, establishing an equilibrium between the undissociated acid and its ions.

Dissociation constant (Ka)

A quantitative measure of the strength of an acid in solution, defined as the equilibrium constant for the dissociation of the acid.

Acid dissociation constant (Ka)

A numerical value that indicates the strength of an acid in solution, defined as the equilibrium constant for the dissociation of the acid into its ions.

pKa

The negative logarithm of the acid dissociation constant (Ka), used to express the strength of an acid.

Dissociation

The process by which a compound breaks down into its constituent ions or molecules in solution.

Equilibrium constant (Ka)

A numerical value that expresses the ratio of the concentrations of products to reactants at equilibrium for a dissociation reaction.

Titration

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

Endpoint

The point in a titration at which the indicator changes color, signaling that the titration is complete.

pH

A measure of the acidity or basicity of a solution, defined as the negative logarithm of the hydrogen ion concentration.

Titration

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

pH

A measure of the acidity or basicity of a solution, calculated as the negative logarithm of the hydrogen ion concentration.

Indicator

A substance that changes color at a specific pH range, used to determine the endpoint of a titration.