What is the half-life of a first-order reaction if it takes 4.4 x 102 seconds for the concentration to decrease from 0.50 m to 0.20 m? 2.5 x 102 s 3.3 x 102s 1.6s 21 s 27 s

The half-life of a first-order reaction is,

Explanation:

All the radioactive reactions follows first order kinetics.

Rate law expression for first order kinetics is given by the equation:

where,  

k = rate constant = ?

t = time taken = 440 s

= initial amount of the reactant = 0.50 M

[A] = left amount =  0.20 M

Putting values in above equation, we get:

The equation used to calculate half life for first order kinetics:

Putting values in this equation, we get:

Therefore, the half-life of a first-order reaction is,

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8

d

explanation: