Consider the nonenzymatic elementary reaction from A → B. When the initial [A] = 20 mM, the reaction velocity is measured as 5 μM/min. Determine the reaction order and calculate the rate constant for the reaction.

• A. 1st order reaction; k= 100 min^-1.
• B. 1st order reaction; k= 0.25 min^-1.
• C. 1st order reaction; k= 2.5 x 10^-4 min^-1.
• D. 1st order reaction; k= 4.0 x 10³ min^-1.
• E. 2nd order reaction; k= 100 min^-1.
• F. 2nd order reaction; k= 0.25 min^-1.
• G. 2nd order reaction; k=2.5 x 10^-4 min^-1.
• H. 2nd order reaction; k= 4.0 x 10³ min^-1.

Answer: (C)

Verified step by step guidance

1. Identify the type of reaction: The problem states that the reaction is nonenzymatic and elementary, which suggests it could be either first-order or second-order.
2. Use the rate law for a first-order reaction: The rate law for a first-order reaction is given by v = k[A], where v is the reaction velocity, k is the rate constant, and [A] is the concentration of A.
3. Substitute the given values into the first-order rate law: Given that the initial [A] = 20 mM and the reaction velocity v = 5 μM/min, substitute these values into the equation v = k[A].
4. Solve for the rate constant k: Rearrange the equation to solve for k, which gives k = v / [A]. Substitute the values to find k.
5. Determine the reaction order: If the calculated k is consistent with the options provided for a first-order reaction, then the reaction is first-order. Otherwise, consider the second-order rate law and repeat the process.