In: Chemistry
A sample of 37Ar undergoes 8540disintegrations/min initially but undergoes 6990disintegrations/min after 10.0 days. What is the half-life of 37Ar in days?
t 1/2= ? days
Since radio active component decays as first order
Let C be the concentration of radioactive compound then rate of decay is following ( let k be the rate constant )
dC/dt = ( - k ) ( C )
dC/C = ( - k ) dt
ln( C/C0 ) = ( - k
)t
( Let C0 be the initial concentration )
( -k ) = ln( C/C0 ) / t
( - k ) = [ ( ln ( 1/2 ) ] / [ t1/2 ]
(
for half concentration t = t1/2 and concentration
become half so c = 1/2 C0 and t = t1/2)
k = ln2/t1/2
t1/2 = ln2/k