Two reactions with different activation energies have the same rate at...
If
Thus, reaction with smaller activation energy will be faster on increasing temperature.
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Two reactions with different activation energies have the same rate at...
The reaction with the smaller activation energy will be faster because the rate of reaction is inversely proportional to the activation energy of that reaction
Two reactions with different activation energies have the same rate at...
Explanation:
When two reactions have the same rate at room temperature, it means that they have the same value for the rate constant (k) at that temperature. The rate constant is related to the activation energy (Ea) through the Arrhenius equation:
k = A * e^(-Ea/RT)
where k is the rate constant, A is the pre-exponential factor, Ea is the activation energy, R is the gas constant, and T is the temperature in Kelvin.
Effect of Temperature on Reaction Rate:
Increasing the temperature of a reaction increases the rate of the reaction. This is because an increase in temperature leads to an increase in the kinetic energy of the reactant molecules, which in turn increases the rate of successful collisions between the reactant molecules.
Effect of Activation Energy:
The activation energy (Ea) is the energy barrier that reactant molecules must overcome in order to undergo the chemical reaction. Reactions with higher activation energies have a larger energy barrier to overcome, and therefore have a slower rate at a given temperature compared to reactions with lower activation energies.
Effect of Temperature on Activation Energy:
Increasing the temperature also affects the activation energy of a reaction. As the temperature increases, the average kinetic energy of the reactant molecules increases, which means that a larger fraction of the molecules have the required energy to overcome the activation energy barrier. This effectively lowers the effective activation energy of the reaction at higher temperatures.
Comparison of Reactions at Higher Temperature:
When the temperature is increased, the effect on the rate of the reaction depends on the activation energy of the reaction.
- The reaction with the smaller activation energy will be faster at the higher temperature because it already has a lower energy barrier to overcome. The increase in temperature further lowers the effective activation energy, making it easier for the reactant molecules to overcome the barrier and undergo the reaction. Therefore, the reaction with the smaller activation energy will have a faster rate at the higher temperature.
- The reaction with the greater activation energy will be slower at the higher temperature because it has a higher energy barrier to overcome. Although the increase in temperature lowers the effective activation energy, it is still relatively higher compared to the reaction with the smaller activation energy. Therefore, the reaction with the greater activation energy will have a slower rate at the higher temperature.
Conclusion:
Therefore, the correct statement is option B: "The reaction with the smaller activation energy will be faster." This is because the reaction with the smaller activation energy already has a lower energy barrier to overcome and the increase in temperature further lowers the effective activation energy, resulting in a faster rate at the higher temperature.