Consider the chemical equation in equilibrium:
[tex]$A(g)+2 B(g) \Leftrightarrow C(g)+D(g)+\text { heat }$[/tex]
What will happen to the equilibrium of this reaction if the temperature is increased?
A. It will shift to the left because heat is released.
B. It will shift to the left because heat is absorbed.
C. It will shift to the right because heat is released.
Answer (2)
The reaction is exothermic, releasing heat in the forward direction.
Increasing the temperature stresses the equilibrium.
According to Le Chatelier's principle, the equilibrium shifts to relieve the stress.
The equilibrium shifts to the left, absorbing heat to counteract the temperature increase. The answer is: It will shift to the left because heat is absorbed.
Explanation
Understanding the Reaction The given chemical reaction is in equilibrium:
A ( g ) + 2 B ( g ) ⇔ C ( g ) + D ( g ) + heat
We need to determine what happens to the equilibrium when the temperature is increased.
Identifying Exothermic Reaction This reaction releases heat as a product, meaning it's an exothermic reaction in the forward direction.
Applying Le Chatelier's Principle Le Chatelier's principle states that if a change of condition (like temperature) is applied to a system in equilibrium, the system will shift in a direction that relieves the stress. In this case, the stress is the increase in temperature.
Determining the Shift Since the forward reaction releases heat, increasing the temperature will cause the equilibrium to shift in the reverse direction (to the left) to absorb the added heat and counteract the change.
Conclusion Therefore, the equilibrium will shift to the left because heat is absorbed in the reverse reaction.
Examples
Consider a scenario where a factory produces a chemical product, and the reaction releases heat. If the factory increases the temperature to speed up the reaction, it might inadvertently shift the equilibrium backward, reducing the product yield. Understanding Le Chatelier's principle helps optimize reaction conditions to maximize product formation while managing heat.
Increasing the temperature of the given exothermic reaction causes the equilibrium to shift to the left, as the system absorbs heat. This is in accordance with Le Chatelier's principle, which states that a system will adjust to counteract changes in conditions. Therefore, the answer is B: It will shift to the left because heat is absorbed.
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