LEARN THESE CHEMISTRY DEFINITIONS

Functional group

An atom or group of atoms that form the centre of chemical activity in the molecule.

Neautralisation

a chemical reaction in which an acid and a base react so that neither is in excess.

Le Chateliers Principle

When an external stress is applied to a system in dynamic chemical equilibrium, the equilibrium point will change in such a way as to counteract the stress'

Anode

the electrode where oxidation takes place

(structural) isomers

Compounds having the same molecular formula but different structural formulae

standard solution

A solution of which the concentration is known exactly, and is unlikely to change for a period of time.

intermolecular forces

a force of attraction between molecules, ions, or atoms in noble gases

Homologous series

a series of similar compounds with the same functional group and have the same general formula , in which each one differs from the previous one by a single CH2 unit

Electrolyte

a substance that can conduct electricity due to the presence of free ions when molten or dissolved in solution

Base

A proton acceptor

Heat of reaction

The net change of chemical potential energy of the system

Electronegativity

A measure of the tendency of an atom to attract a bonding pair of electrons

Hydrolysis of a salt

as a reaction of an ion (from a salt) with water.

Ionisation

the reaction of a molecular substance with water to produce ions.

Acid

A proton donor

Catalyst

A substance that increases the rate of the reaction but remains unchanged at the end of the reaction

Activation energy

The minimum kinetic energy required to start a chemical reaction/ the kinetic energy required to form the activated complex

Activated complex

Is a high energy, unstable, temporary transition state between the reactants and the products

A weak acid

as an acid that only ionises partially in an aqueous solution.

Salt as a substance

in which the hydrogen of an acid has been replaced by a cation.

Reducing agent

a substance that donates electrons

Reaction rate

The change in concentration per unit time of either a reactant or product

Covalent bond

The sharing of at least one pair of electrons between two atoms

Hydrocarbons

compounds that contain only carbon and hydrogen

Amphoteric Substance

a substance that can act as either an acid or a base.

Oxidation

the loss of electrons

Closed system

A system in which no mass (reactants or products) is transferred into or out of the system.

Dynamic chemical equilibrium

When the rate of the forward reaction is equal to the rate of the reverse reaction.

Strong acid

An acid that ionises completely in an aqueous solution.

Weak acid

An acid that only ionises partially in an aqueous solution.

Strong base

A base that dissociates completely in an aqueous solution.

Weak base

A base that only ionises partially in an aqueous solution.