Formula Used:
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Definition: This represents the fraction of molecular collisions that result in a successful chemical reaction.
Purpose: It helps chemists understand reaction efficiency and predict reaction rates under different conditions.
The calculator uses the formula:
Where:
Explanation: The ratio of the rate constant to the pre-exponential factor gives the fraction of collisions that have sufficient energy to overcome the activation barrier.
Details: Understanding this fraction helps in reaction optimization, catalyst design, and predicting how reaction rates change with temperature.
Tips: Enter the rate constant and pre-exponential factor (default 15 1/s). Both values must be > 0.
Q1: What does a small fraction value indicate?
A: A small fraction means only a small portion of collisions are effective, suggesting a high activation energy barrier.
Q2: How does temperature affect this fraction?
A: Higher temperatures increase the fraction as more molecules have sufficient energy to overcome the activation barrier.
Q3: What's a typical value for the pre-exponential factor?
A: For many reactions, A ranges from 10^10 to 10^14 1/s, but this varies widely depending on the reaction.
Q4: Can this fraction be greater than 1?
A: No, since k ≤ A, the fraction should always be between 0 and 1.
Q5: How is this related to the Arrhenius equation?
A: The fraction equals e^(-Ea/RT) in the Arrhenius equation, where Ea is activation energy, R is gas constant, and T is temperature.