Experiments to examine dynamic equilibrium and Le Chateliers principle

Authors Avatar by petraatosgmailcom (student)

2.0 Abstract:

From the experiment, we become understand about dynamic equilibrium and Le Chatelier’s principle. Besides, we able to observe the change of an equilibrium when the concentration of a reactant or product is altered. We also know how to predict the effect of concentration changes on chemical equilibrium.

This report shows, whenever a system in equilibrium is disturbed the system will adjust itself in such a way that the effect of the change will be reduced or moderated. Changing the concentration of a chemical will shift the equilibrium to the side that would reduce that change in concentration. The chemical system will attempt to partly oppose the change affected to the original state of equilibrium. In turn, the rate of reaction, extent, and yield of products will be altered corresponding to the impact on the system. The principle is used to manipulate the outcomes of reversible reactions, often to increase the yield of reactions.

3.0 Introduction:


In a chemical reaction, chemical equilibrium is the state in which both reactants and products are present in concentrations which have no further tendency to change with time. This state results when the forward reaction proceeds at the same rate as the reverse reaction. A common misconception is that the concentrations are equal, which is incorrect.  Equilibrium is when the forward and reverse reactions occur at the same rate.

Le Chatelier is one of the central concepts of chemical equilibria. Le Chatelier's principle can be stated as follows: A change in one of the variables that describe a system at equilibrium produces a shift in the position of the equilibrium that counteracts the effect of this change.

Le Chatelier's principle describes what happens to a system when something momentarily takes it away from equilibrium. There are three changes that will affect the position of equilibrium momentarily. First, changing the concentration of one of the components of the reaction. Second, changing the pressure on the system. Third, changing the temperature at which the reaction is run.


Observe the effect of an applied stress on chemical system at equilibrium. A reversible reaction is a reaction in which both the conversion of reactants to products and the conversion of products to reactants occur simultaneously.

  1. Materials and Methods:


A set of 4" and 6" test tubes, test tube rack, pipettes, 100 mL graduated cylinder, 250 mL beaker, saturated sodium chloride solution, concentrated hydrochloric acid, 0.1 M iron (III) chloride, 0.1 M potassium thiocyanate, 6 M NaOH, 50% NaOH solution, 0.1 M acetic acid, methyl orange, sodium acetate, sodium chloride, 0.1 M potassium chromate, 6 M nitric acid, bismuth chloride, 1 M cobalt (II) chloride.

  1. Methods

As you finished each procedure, the content of the test tubes is disposed as directed by your instructor, and the glassware is washed thoroughly with soap and water, and then all equipment and chemicals are returned to the designated areas.

  1. The Saturated Sodium Chloride Solution Equilibrium
Join now!

5 mL of saturated sodium chloride (NaCl) solution is added to a 4" test tube. Its appearance is recorded. Several drops of concentrated hydrochloric acid (HCl) is added to this solution. Your observations are recorded.

  1. The Iron (III) Thiocyanate Ion Equilibrium

2 mL of 0.1 M iron (III) chloride (FeCl) solution and 2 mL of 0.1 M potassium thiocyanate (KSCN) solution is added to 100 mL of water in a 250 mL beaker. This stock solution is stirred until it is homogeneous. Observations are recorded.

5 mL of the stock ...

This is a preview of the whole essay