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 : The value of rate constant is,

Explanation :

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

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

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

Therefore, the value of rate constant is,

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.