Question

Consider the following first-order reaction: A → B. The concentration of A at the start of the reaction is 4.17 M and after 4.84 s is 3.56 M. (a) Using the integrated rate law for a first-order reaction, calculate the value of the rate constant.

Answer 1

Answer : The value of rate constant is, $0.0327s^{-1}$

Explanation :

First we have to calculate the rate constant, we use the formula :

Expression for rate law for first order kinetics is given by:

$k=\frac{2.303}{t}\log\frac{a}{a-x}$

where,

k = rate constant  = ?

t = time passed by the sample  = 4.84 s

a = initial concentration = 4.17 M

a - x = concentration after time 4.84 s = 3.56 M

Now put all the given values in above equation, we get

$k=\frac{2.303}{4.84}\log\frac{4.17}{3.56}$

$k=0.0327s^{-1}$

Therefore, the value of rate constant is, $0.0327s^{-1}$