Lavossiers and Laplace Law
It states that heat absorbed while decomposing a compound Is the same as the heat liberated while forming a compound but the sign changes.
Hess Law of constant heat summation
It states that the energy change involved in a reaction is independent on the path reaction.
Le Chateliers Principle
It states that when external influence in terms of changes in concentration, pressure or temperature is imposed on anybody in equilibrium, that the body tends to shift so as to cancel the effect of these external constraints.
However, for this level, we do not use (1) and (2), we only make use of (3).
NB: – A body is in chemical equilibrium when the rate of forward reaction equals the rate of backward reaction.
It states that:
(a) Chemical reaction results as a result of collision between molecules
(b) Not all collisions result in a chemical reaction (they are non-effective). However, those collisions, which result in chemical reaction are effective collision.