Problem: Do the equilibrium concentrations of the reactants and products depend on their initial concentrations?

We’re asked to determine if the equilibrium concentrations of the reactants and products depend on their initial concentrations.

Recall that a reaction is at equilibrium when the rate of the forward reaction (favors products) is equal to the rate of the reverse reaction (favors reactants).

This means that:

• At equilibrium, there is no observable change in the concentration of both the products and reactants
• In other words, the ratio that expresses the relationship between the amounts of products and reactants present at equilibrium is constant; known as the equilibrium constant, K.  The expression for the equilibrium constant, K is: 

$\boxed{\mathbf{K}\mathbf{=}\frac{\mathbf{products}}{\mathbf{reactants}}}$

• Using an equilibrium constant, K, we can use an ICE chart to determine the equilibrium concentrations of species.