Equilibrium is a process that involves lots of movement. Reactants are constantly converted to products, while at the same time, products are converted back to reactants. When those two processes are occuring at the same rate, equilibrium is reached.


The following video can help you visualize what's occuring at equilibrium.





Want to see another demonstration of chemical equilibrium? Check out this video to see how changing concentrations and temperature affects chemical equilibrium.




 At equilibrium, the amounts of reactants and products are represented in terms of the equilibrium constant, K. For the generic chemical reaction: aA + bB --> mM + nN, the equilibrium constant is expressed as:

where [A] and [B] are the molar concentrations of the reactants, [M] and [N] are the molar concentrations of the products, and a, b, m, and n are the stoichiometric coefficients from the balanced chemical reaction.


The value of the equilibrium constants tells chemists which side of the reaction the equilibrium lies on, whether more reactants are present or more products. If the products are favored, the concentrations of the products will be larger than the concentrations of the reactants and the equilibrium constant, K, will be large. If the reactants are favored, the concentration of the reactants will be larger than the concentration of the products, and the equilibrium constant, K, will be very small.



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