Altering Equilibrium Conditions Le Chateliers Principle

When equilibrium is established, (a) the amount of H2(g) will be 1.00 mol (b) the amounts of all reactants and products will be greater than 1.00 mol (c) the amounts of all reactants and products will be less than 1.00 mol (d) the amount of C02(g) will be greater than 1.00 mol and the amounts of CO(g), H20(g), and H2(g) will be less than 1.00 mol (e) the amounts of reactants and products cannot be predicted and can only be determined by analyzing the equilibrium mixture. 

At times, we want only to make qualitative statements about the direction of a net change, whether the amount of a substance will have increased or decreased when equilibrium is reached, and so on. Also, we may not have the data needed for a quantitative calculation. In these cases, we can use a statement attributed to the French chemist Henri Le Chatelier (1884). Le Chatelier s principle is hard to state unambiguously, but its essential meaning is stated here. 

When an equilibrium system is subjected to a change in temperature, pressure, or concentration of a reacting species, the system responds by attaining a new equilibrium that partially offsets the impact of the change. 

As we will see in the examples that follow, it is generally not difficult to predict the outcome of changing one or more variables in a system at equilibrium. 

Effect of Changing the Amounts of Reacting Species on Equilibrium 

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