1 Le Chatelier's principle states that if a change in conditions (such as temperature, pressure, or concentration of reactants) is applied to a system at equilibrium, the system will shift in a

• As the temperature increases from 300 K to 700 K, the value of $K_c$ significantly increases (from $1.00 \times 10^{-1}$ to $1.20 \times 10^4$).
• An increase in $K_c$ with increasing temperature means that the equilibrium shifts to favor the products (right side of the reaction).
• According to Le Chatelier's principle, if increasing the temperature shifts the equilibrium to the product side, the forward reaction must be endothermic (absorbs heat). This is because the system tries to absorb the added heat by favoring the endothermic direction.

• Increasing the concentration of the reactant, $\text{N}_2\text{O}_4\text{ (g)}$.
• Adding a suitable catalyst.

The reaction is: $\text{N}_2\text{O}_4\text{ (g)} \rightleftharpoons 2\text{NO}_2\text{ (g)}$

Reason: The equilibrium constant ($K_c$) is a constant value for a specific reaction at a given temperature. It does not change with changes in the concentration of reactants or products. Adding more $\text{N}_2\text{O}_4$ will cause the equilibrium to shift to the right to consume the added reactant, but the ratio of products to reactants at equilibrium (i.e., $K_c$) will remain unchanged as long as the temperature is constant.