Chemical equilibrium the law of mass action

The conditions of chemical equilibrium can most easily be derived from the 

The velocity with which A and B react is proportional to their concentrations, or Vi = kt x [A] x [B] 

At equilibrium the velocities of the reverse and forward reactions are equal (the equilibrium is a dynamic and not a static one) and therefore 

K is the equilibrium constant of the reaction. Its value is independent of the concentrations of the species involved it varies slightly with temperature and pressure. 

The expression may be generalized for more complex reactions. For a reversible reaction represented by the equation 

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