Problem 86 - Chemistry: An Atoms-Focused Approach

Question

According to the Arrhenius equation, does the activation energy of a chemical reaction depend on temperature? Explain your answer.

Step-by-Step Solution

Answer

Answer: No, the activation energy (Ea) of a chemical reaction does not depend on temperature according to the Arrhenius equation. Ea is a constant for a specific reaction, while the rate of the reaction depends on temperature through the exponential term in the equation.

Step 1: Arrhenius Equation

The Arrhenius equation describes the relationship between the rate constant (k) of a chemical reaction and temperature (T). It is expressed as follows: k = Ae^(-Ea/RT) where k is the rate constant, A is the pre-exponential factor (which depends on the reaction but not on temperature), Ea is the activation energy, R is the gas constant (8.314 J/mol K), and T is the temperature in Kelvin.

Step 2: Analyzing the Activation Energy

In the equation, the activation energy (Ea) is a constant for a particular reaction, independent of the temperature. It represents the minimum energy required for the reactants to undergo a chemical reaction.

Step 3: Temperature Dependency

The temperature dependency in the Arrhenius equation is represented by the exponential term, e^(-Ea/RT). As the temperature (T) increases, the exponent becomes less negative, and the exponential term becomes larger. This means that the rate constant (k) of the reaction increases with temperature, and the reaction occurs faster.

Step 4: Conclusion

According to the Arrhenius equation, the activation energy (Ea) of a chemical reaction does not depend on temperature. The activation energy is a constant for a specific reaction, while the rate of the reaction depends on temperature through the exponential term in the equation.