Question

Predict whether the equilibria I) CO(g) + H2O(g) ⇀↽ CO2(g) + H2(g), ∆H◦ = −41 kJ II) N2O4(g) ⇀↽ 2 NO2(g), ∆H◦ = +57 kJ will shift toward products or reactants with a temperature increase.

Answer 1

I) Shift to the side of the reactants

II) shift to the side of the products

Step-by-step explanation:

Step 1: Data given

If the temperature is increased, the system will, as reaction, release less heat .

This means for an exothermic reaction (ΔH°<0), the balance will shift to the left. To the side of the reactants.

For an endothermic reaction, the balance will shift to the right. The side of the products.

When the temperature decreases, the system will produce more heat and the balance will shift to the right. To the side of the products.

For an endothermic reaction, the balance will shift to the left. The side of the reactants.

Exothermic reaction = (ΔH°<0)

Endothermic reaction (ΔH°>0)

Step 2: I) CO(g) + H2O(g) ⇀↽ CO2(g) + H2(g), ∆H◦ = −41 kJ

Since ΔH°<0, this is an exothermic reaction.

If the temperature is increased, the system will, as reaction, release less heat .

This means for an exothermic reaction (ΔH°<0), the balance will shift to the left. To the side of the reactants.

Step 3: II) N2O4(g) ⇀↽ 2 NO2(g), ∆H◦ = +57 kJ

If the temperature is increased, the system will, as reaction, release more heat .

This means for an endothermic reaction (ΔH°>0), the balance will shift to the right. To the side of the products.

Answer 2

I) Toward reactants

II) Toward products

Step-by-step explanation:

In order to predict the shift in the equilibria with a temperature increase, we need to consider Le Chatelier's Principle: if a system at equilibrium suffers a perturbation, it will react to counteract the effect of such perturbation.

I) CO(g) + H₂O(g) ⇆ CO₂(g) + H₂(g), ∆H° = −41 kJ

Since ∆H° < 0, the reaction is exothermic. If the temperature is increased, the equilibrium will shift toward the reactants, to absorb heat and reduce the temperature.

II) N₂O₄(g) ⇄ 2 NO₂(g), ∆H◦ = +57 kJ

Since ∆H° > 0, the reaction is endothermic. If the temperature is increased, the equilibrium will shift toward the Products, to absorb heat and reduce the temperature.