Final answer:
The four factors that can affect the position of equilibrium include concentration, pressure and volume, temperature, and catalysts. Of these, only temperature can change the value of the equilibrium constant (K).
Step-by-step explanation:
Four factors that can affect the position of equilibrium in a chemical reaction are concentration, pressure and volume, temperature, and the presence of catalysts. Out of these factors, only changes in temperature can alter the value of the equilibrium constant (K).
When the concentration of reactants or products is changed, the system will shift towards the side that opposes the change, in accordance with Le Chatelier's principle, but this will not change the value of K. Changes in pressure and volume affect the position of equilibrium only in systems with gases, particularly when there is a change in the total number of gas molecules. Nevertheless, such changes do not affect the value of the equilibrium constant, which is dependent on partial pressures or concentrations.
The introduction of a catalyst speeds up both the forward and reverse reactions equally, thereby reaching equilibrium faster without affecting the position of equilibrium or altering the value of K. Temperature is unique because it influences the rate at which reactions occur. Since equilibrium constants are determined by the relative rates of the forward and reverse reactions, a change in temperature can cause the equilibrium constant to change. It is the enthalpy change of the reaction that can be used to predict the effect of a temperature change on K.