Equilibrium Concentrations in a Reaction

Reversible reactions eventually reach an equilibrium condition in which the concentrations of all reactants and products are constant. Equilibrium can be disturbed, however, by the addition or removal of either a reactant or product. The graph on the right shows how the concentrations of the reactants and product of a reaction change when equilibrium is disturbed. Use the graph to answer the following questions. 

Explain the shapes of the curves for the three gases during the first 2 minutes of the reaction. 

At approximately what time does the reaction reach equilibrium How do you know equilibrium has been reached  

Describe the change made in the system 4 minutes into the reaction. Tell how you know the change was made. 

At what time does the system return to equilibrium  

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