If the activation energy required for a chemical reaction were reduced, what would happen to the rate of the reaction?
A. The rate would increase.
B. The rate would decrease.
C. The rate would remain the same.
D. The rate would be zero.
Answer (2)
The activation energy is the minimum energy required for a chemical reaction to occur.
The Arrhenius equation ( k = A e − RT E a ) relates the rate constant to the activation energy.
Reducing the activation energy increases the rate constant.
An increase in the rate constant leads to an increase in the rate of the reaction, so the final answer is: The rate would increase.
Explanation
Understanding the Problem The question explores the relationship between activation energy and the rate of a chemical reaction. We need to determine what happens to the reaction rate when the activation energy is reduced.
Recalling the Arrhenius Equation The activation energy ( E a ) is the minimum energy required for a chemical reaction to occur. The rate of a chemical reaction is related to the activation energy by the Arrhenius equation: k = A e − RT E a where:
k is the rate constant
A is the pre-exponential factor
E a is the activation energy
R is the gas constant
T is the temperature
Analyzing the Effect of Reducing Activation Energy From the Arrhenius equation, we can see that the rate constant k is inversely related to the activation energy E a . The term − RT E a is in the exponent. If we reduce the activation energy E a , the value of − RT E a becomes less negative (i.e., it increases).
Determining the Change in Rate Constant Since the exponent increases (becomes less negative), the value of e − RT E a increases. Because the rate constant k is directly proportional to e − RT E a , the rate constant k also increases.
Concluding the Effect on Reaction Rate The rate of the reaction is directly proportional to the rate constant k . Therefore, if the rate constant k increases, the rate of the reaction also increases.
Final Answer Therefore, if the activation energy required for a chemical reaction is reduced, the rate of the reaction would increase.
Examples
Imagine you're pushing a box over a hill. The height of the hill represents the activation energy. If the hill is lower (less activation energy), it's easier to push the box over, and you can do it faster (the reaction rate increases). In chemical reactions, enzymes act as catalysts to lower the activation energy, speeding up the reaction, much like making the hill shorter.
If the activation energy required for a chemical reaction is reduced, the rate of the reaction would increase. This is due to the relationship defined by the Arrhenius equation, which shows that lower activation energy leads to a higher rate constant. Therefore, the correct answer to the question is A: The rate would increase.
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