The rate constant for a particular second-order reaction is 0.47 m-1s-1. if the initial concentration of reactant is 0.25 mol/l, it takes s for the concentration to decrease to 0.13 mol/l.

Answer : The time taken by the reaction is 7.856 seconds.

Explanation :

The expression used for second order kinetics is:

where,

k = rate constant =

t = time = ?

= final concentration = 0.13 mole/L = 0.13 M

= initial concentration = 0.25 mole/L = 0.25 M

Now put all the given values in the above expression, we get:

Therefore, the time taken by the reaction is 7.856 seconds.

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)