Question

The rate of the reaction is 1.5 * 10 ^ - 2 * M/s when the concentration of A is 0.38 M. Calculate the rate constant if the reaction is first order in A. Include the units of the rate constant. Be sure your answer has the correct number of significant digits.

Answer 1

The rate constant (k) for the first-order reaction is calculated as 3.9 x 10^-2 s^-1, considering two significant digits.

Step-by-step explanation:

The question asks us to calculate the rate constant (k) for a first-order reaction where the rate is given as 1.5 x 10-2 M/s when the concentration of A is 0.38 M. For a first-order reaction, the rate law is expressed as rate = k[A], where [A] is the concentration of the reactant. Re-arranging this formula to solve for the rate constant gives us k = rate / [A].

Plugging in the values from the question:

k = (1.5 x 10-2 M/s) / (0.38 M)

k = 0.03947 s-1

Now, keeping in mind the correct number of significant digits, we get:

k = 3.9 x 10-2 s-1 (to two significant digits)

The units of the rate constant for a first-order reaction are s-1, which align with the answer above.