Final answer:
Altering the concentration of reactants or products in a system at equilibrium will cause a shift in the equilibrium position according to Le Chatelier's principle, to counteract the change and reestablish a new equilibrium state.
Step-by-step explanation:
When the concentration of a reactant or product in a chemical equilibrium is altered, this change can shift the position of the equilibrium. This response is guided by Le Chatelier's principle, which states that the system will adjust in a way to counteract the change. If the concentration of a reactant is increased, the system will respond by shifting the equilibrium to produce more product, thus consuming the added reactant. Conversely, if the concentration of a product is increased, the equilibrium will shift to form more reactants, using up the excess product.
This effect of concentration changes is crucial in many industrial processes where yields need to be maximized, as well as in biological systems where it helps maintain homeostasis. The fundamental concept underlying this behavior is that a system at equilibrium is in a delicate balance, and altering concentrations of the substances involved will disturb this balance and induce a shift to reestablish a new equilibrium state.