Ok I may be young but combine the two reactions to create a compund
Hypochlorous acid is a weak acid. The 
value for the dissociation of HOCl is 
The amount of chemical energy is equal to the amount of heat and light energy.
This is due to the principle of conservation of energy, which states that the total energy of a system remains constant.
We are given the following equation:
y = y0 e^-0.0001216 t
where y = 1/5 y0, y0 is the original amount
So solving for time t:
1/5 y0= y0 e^-0.0001216 t
t = 13,235.51 years
So the human died about 13235.5 years ago
