What factors influence the concentrations of reactants and products at equilibrium?

The concentrations of reactants and products at equilibrium are influenced by the conditions of the system. This includes factors such as temperature, pressure, and the concentration of reactants and products. According to Le Chatelier's principle, if a system at equilibrium experiences a change in conditions, the equilibrium position will shift to counteract that change and restore a new equilibrium.

For example, if the temperature of a reversible reaction is increased, the equilibrium may shift towards the endothermic direction to absorb the added heat. Similarly, changes in pressure can affect systems involving gases, where increasing pressure shifts the equilibrium toward the side with fewer gas molecules, thereby altering the concentrations of reactants and products.

While temperature and pressure are significant factors, they are specifically aspects of the broader category of "conditions." This is why the answer encompassing all such influencing factors is accurate. Understanding this concept helps in predicting how a change in conditions will affect a chemical equilibrium, making it crucial for studying chemical reactions and their dynamics.