Chemical equilibrium "the equilibrium constant"
The law of mass action: states that the rate of chemical reaction is proportional to the active
masses of the reacting substances .The active masses mean the concentration of the
reacting substances in the case of solid or liquid in the case of gaseous reactants with partial
pressures.
Mole fraction of a substance in a phase is the number of molecules of the substance present
divided by the total number of molecules present in the phase. The active masses of pure
solid or liquid can be considered to be unity for the purpose of this approach.
Rate of forward reaction=k1cAcB
Rate of reverse reaction =k2cDcC
The two reactions will proceed until eventually the rate of forward and reverse reactions are
the same, provided the temperature and pressure remain unaltered.The system is said to be
in a state of chemical equilibriuim.
Kp=kc.RT
The vant- hoff isotherm:
The Clausius clapeyron equation:
This equation can be used to calculate the latent heat of evaporation by measuring the
vapour pressure of a substance at various and is important in vacuum metallurgy where the
vapour pressure of certain elements can be high enough to cause serious evaporation losses