Rate constant of a reaction is 1.6 x 10–2 and preexponential factor is...
Rate constant of a reaction is 1.6 x 10–2 and preexponential factor is...
Rate Constant and Preexponential Factor
The rate constant of a chemical reaction, denoted as k, is a proportionality constant that relates the rate of the reaction to the concentrations of the reactants. It represents the speed at which the reaction occurs.
The preexponential factor, denoted as A, is a constant that accounts for the frequency of molecular collisions and the orientation of the colliding molecules. It is a measure of the likelihood that a reaction will occur.
Relationship between Rate Constant and Preexponential Factor
The rate constant (k) can be expressed as the product of the preexponential factor (A) and the exponential factor (e^(-Ea/RT)), where Ea is the activation energy, R is the gas constant, and T is the temperature in Kelvin.
Therefore, k = A * e^(-Ea/RT)
Calculating the Effective Fraction of Molecules
To calculate the effective fraction of molecules that undergo chemical transformation, we need to determine the value of A from the given information.
Given:
k = 1.6 x 10^(-2)
A = 32
We can rearrange the equation for the rate constant to solve for A:
A = k / e^(-Ea/RT)
Since the value of the activation energy and temperature is not provided, we cannot determine the exact value of A. However, we can still compare the given options to determine the most appropriate answer.
Comparing the Given Options
Let's calculate the value of A for each option and compare them:
(1) A = 2 x 10^(-4) / e^(-Ea/RT)
(2) A = 2 x 10^(-3) / e^(-Ea/RT)
(3) A = 4 x 10^(-6) / e^(-Ea/RT)
(4) A = 5 x 10^(-4) / e^(-Ea/RT)
Since the exponential factor is always positive, the value of A will be larger for smaller values of the denominator. Therefore, the option with the smallest denominator will have the largest value of A.
Comparing the denominators:
(1) e^(-Ea/RT) is larger than e^(-Ea/RT) for any positive Ea and RT
(2) e^(-Ea/RT) is larger than e^(-Ea/RT) for any positive Ea and RT
(3) e^(-Ea/RT) is larger than e^(-Ea/RT) for any positive Ea and RT
(4) e^(-Ea/RT) is larger than e^(-Ea/RT) for any positive Ea and RT
Therefore, the option with the smallest denominator is (3) 4 x 10^(-6).
Hence, the effective fraction of molecules to undergo chemical transformation is 4 x 10^(-6).
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