Question

In the equilibrium ABsolid​⇌Agas​+Bgas​, if the equilibrium concentration of A is doubled, what happens to the reaction?

Answer 1

When the equilibrium concentration of A in the reaction AB(solid) ⇌ A(gas) + B(gas) is doubled, the reaction shifts toward forming more products, increasing the production of A(gas) and B(gas), until a new equilibrium is established.

Step-by-step explanation:

In the equilibrium scenario AB(solid) ⇌ A(gas) + B(gas), when the equilibrium concentration of A is doubled, there is a shift in the reaction dynamic according to Le Chatelier's principle. The principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract the change. In this case, doubling the concentration of A(solid) leads the reaction to shift towards the products (to the right), which increases the production of A(gas) and B(gas). This shift towards the products is necessary to re-establish equilibrium, where the rate of the forward reaction equals the rate of the reverse reaction, and the macroscopic properties of the system remain constant.

According to the equation ΔG = ΔG° + RTlnQ, as the reaction reaches equilibrium, the value of ΔG approaches zero. Doubling the concentration of the reactant A increases the reaction quotient Q. Since ΔG depends on Q relative to K (the equilibrium constant), which reflects whether the system is at equilibrium, this change will initially make ΔG more negative, indicating that the formation of products is still favored until equilibrium is restored.

It's important to consider that the increase in the concentration of A and subsequent shift in the reaction will change the equilibrium concentrations of both reactants and products. The exact new equilibrium composition can be determined by performing a calculation using an ICE table (Initial, Change, Equilibrium) and the balanced equation to calculate the changes in concentrations of all species involved. Fundamentally, the change in the conditions leads to a temporary imbalance, and the system will adjust to the new conditions to reach a new equilibrium state.

Answer 2

In the equilibrium AB_solid⇌ A_gas + B_gas, doubling the equilibrium concentration of A will shift the equilibrium to the right, leading to an increase in the production of B_gas. This shift is a response to maintaining the equilibrium constant (K), and the reaction rate temporarily increases due to more frequent particle collisions.

Step-by-step explanation:

Impact of Doubling the Concentration of a Reactant on Equilibrium

In the context of the equilibrium ABsolid⇌ Agas + Bgas, if the equilibrium concentration of A is doubled, according to Le Chatelier's principle, the system will respond by shifting the equilibrium to counteract this change. This means that the system will try to consume the additional A, thus shifting the equilibrium to the right and increasing the production of Bgas. The overall effect is an attempt to re-establish equilibrium at a new position where there are higher concentrations of both Agas and Bgas.

When we consider equilibrium constant expressions and the reaction quotient (Q), we can use the equation ΔG = ΔG° + RTlnQ to understand this shift. Since Q will increase in response to the increased concentration of Agas, the reaction will proceed in the direction in which ΔG becomes more negative, ultimately pushing towards producing more Bgas until equilibrium is re-established. The resulting equilibrium state will be characterized by proportional changes in the concentrations of reactants and products, maintaining the equilibrium constant (K) at a constant value for a given temperature. However, shifting the equilibrium does not change the value of K unless the temperature of the system is changed.

An increase in temperature typically favors the endothermic direction of a reaction, based on the sign of the enthalpy change (ΔH). For the reaction mentioned above, without knowing the enthalpy change, predicting the exact effect of a temperature increase on product and reactant concentrations cannot be accurately described. However, in general, adding heat shifts the equilibrium in the direction that absorbs the heat.

As a simple analogy, if the concentration of a reactant is doubled in a reaction, similar to the doubling of Agas, the reaction rate will increase due to the heightened probability of particle collisions. However, this increase in reaction rate is temporary as the system will adjust to re-establish equilibrium.