The radioactive decay obeys first order kinetics
the rate law expression for radioactive decay is
Where
A0 = initial concentration
At = concentration after time "t"
t = time
k = rate constant
For first order reaction the relation between rate constant and half life is:
Let us calculate k
k = 0.693 / 72 = 0.009625 years⁻¹
Given
At = 0.25 A0
time = 144 years
So after 144 years the sample contains 25% parent isotope and 75% daughter isotopes**
Simply two half lives
Explanation:
The given cell reaction is as follows.
Hence, reactions taking place at the cathode and anode are as follows.
At anode ; Oxidation-half reaction : ...... (1)
At cathode; Reduction-half reaction : ....... (2)
Hence, balance the half reactions by multiplying equation (1) by 2 and equation (2) by 3.
Therefore, net cell reaction is as follows.
Net reaction:
Thus, we can conclude that the overall cell reaction is as follows.
The reaction is given by
Barium goes underneath beta decay to form Ceaseum