6 - Chemistry Reactions

Physical Change

A change that can be easily reversed without forming new products.

Chemical Change

A change that is difficult to reverse, resulting in the formation of new substances.

Collision Theory

For particles to react, they must collide with sufficient energy, known as activation energy.

Catalyst

A substance that speeds up a chemical reaction without being consumed, often by lowering activation energy.

Reversible Reaction

A reaction in which products can turn back into reactants, achieving dynamic equilibrium.

Equilibrium

A state in which the rate of the forward reaction equals the rate of the backward reaction, with constant concentrations.

Le Châtelier's Principle

If an equilibrium is disturbed, the system shifts to counteract the change and restore equilibrium.

Redox Reaction

A reaction in which reduction and oxidation occur simultaneously, involving the transfer of electrons.

Oxidation

The gain of oxygen or loss of electrons, resulting in an increase in oxidation state.

Reduction

The loss of oxygen or gain of electrons, resulting in a decrease in oxidation state.

Ionic Equations

Equations that show only the particles involved in the reaction, excluding spectator ions.