What is the final step of the four-step process for analyzing changes in equilibrium?
The correct answer and explanation is:
The final step of the four-step process for analyzing changes in equilibrium is to predict the direction of the shift. This involves determining whether the system will shift to the left or right in response to a disturbance.
In the context of chemical equilibria, the system will shift in a direction that counteracts the change imposed by the disturbance. This is in accordance with Le Chatelier’s Principle, which states that when a system at equilibrium is disturbed by a change in concentration, temperature, or pressure, the system will adjust to minimize the effect of that change.
To predict the shift, one must consider the nature of the disturbance:
- Change in Concentration: If the concentration of reactants or products is increased, the system will shift in the direction that reduces the concentration of the added substance. For example, if more reactant is added, the system will shift to the right to produce more products.
- Change in Temperature: For exothermic reactions, an increase in temperature will shift the equilibrium to the left (favoring the reactants), while for endothermic reactions, the shift will be to the right (favoring the products).
- Change in Pressure: If the pressure is increased, the equilibrium will shift toward the side with fewer moles of gas to reduce pressure. Conversely, if pressure is decreased, the system will shift toward the side with more moles of gas.
After determining the direction of the shift, the system will adjust the concentrations of the reactants and products until a new equilibrium is established. This step ensures that the equilibrium constant (K) remains unchanged unless the temperature is altered, as it is only affected by temperature.
Thus, this final step focuses on predicting and understanding how the system will respond to maintain balance following a disturbance.