Question

What is the numerical value of the rate constant for a reaction in which [A] is reduced from 0.380 M to 0.215 M in a span of 26.3 s? Assume the units of the rate constant are s-1. Please enter your response to three of significant figures using E notation. For example, to report 1347.54 to three significant figures, type: 1.35E3

Answer 1

Answer:

k = 2.17E-2 s-1

Explanation:

Initial Concentration [A]o = 0.380 M

Final Concentration [A] = 0.215 M

time, t = 26.3 s

Unit of rate constant =  s-1

Rate constant = ?

The units of the rate constant depends on the order of the reaction. This is a first order reaction due to the units.

The integral rate law for a first order reaction is;

ln[A] = ln[A]o - kt

ln(0.215) = ln(0.380) - k(26.3)

ln(0.215) - ln(0.380) = - k(26.3)

- k(26.3) = -0.57

k = 0.57 / 26.3 = 0.02167

Reporting to three significant figures using E notation;

k = 2.17E-2 s-1