Before beginning with the topic of our discussion, the derivation of equilibrium expression, we have to re-examing the following thermodynamic convention.
1. Any system to which substance is added or substance are ken away from, the system, or a system of which chemical reaction take place is refer to as open system.
Open system as you must have learn before, are system that facilitate the exchange of heat and quantities from the system with it surrounding or environment.
2. A chemical reaction that include many numbers of substance can be represented with the following equation ΣiViAi = 0
Ai stands for a chemical substance on it temperature and pressure, while Vi is refer to as stoichiometric coefficient of Ai also know that V signified a positive value for product and negative value for reactant in chemical reaction equation for easy illustration we use the following chemical equation for example;
H2(g) + 1/2O2(g) = H2O