Dynamic Equilibrium

 An essential component needed to fully understand many chemical systems is the concept known as a dynamic equilibrium. By referring to a system as an equilibrium, it is implied that the process goes in two directions at the same time, forwards and backwards. By referring to the system as being dynamic, it is implied that the process is continually exchanging materials, i.e., reactants are always making products and products are always making reactants.

 The concept of a dynamic equilibrium is represented by the following equation:

The double arrow is used to represent both a forward and a reverse reaction, happening simultaneously. The position of the Heat term will depend upon the specifics of the reaction that is taking place.

 LeChatelier's Principle:

 When a stress is introduced into a system at equilibrium, the equilibrium will rearrange itself in order to relieve the stress.

 There are several ways to introduce a stress into a system.

  1. Change the concentration of a component of the reaction.
  2. Add or remove heat.
  3. Change the pressure of the system.
  4. Add a catalyst.

The equilibrium system that is associated with the liquid phase when described by the Flickering Cluster Theory is
 According to Le Chatelier's Principle, if the heat in this system is increased, then the system will shift to the right. In other words, more gas phase is produced and less solid state exists. The system will appear with a greater amount of gas phase, and smaller numbers of crystals.  
   According to Le Chatelier's Principle, if the heat in this system is decreased, then the system will shift to the left. In other words, more solid phase is produced and less gas state exists. The system will appear with a greater number of larger crystals, and a smaller amount of the gas phase.

 If the logic of these arguments are carried to their logical conclusions, then the following ideas will hold:

  • If the temperature is continually increased, the system will eventually become all gas phase. Thus explaining the concept of boiling, or converting the system into a gas.
  • If the temperature is continually decreased, the system will eventually become all solid phase. Thus, explaining the concept of freezing, or converting the system into a solid.
 The idea of trying to describe a liquid with the Flickering Cluster Theory provides chemists with good explanations of a variety of concepts that are associated with the liquid state. The next page will explain the details of some of these ideas.

 Questions and comments should be sent to :
   kdrews@bcpl.net  
Updated September 1, 2000