Respuesta :
Answer: 3.02 days
Explanation: This is a type of radioactive decay and all the radioactive process follow first order kinetics.
Equation: Expression for rate law for first order kinetics is given by:
[tex]k=\frac{2.303}{t}\log\frac{a}{a-x}[/tex]
where,
k = rate constant
t = time taken for decay process
a = initial amount of the reactant
(a - x) = amount left after decay process
Putting values in above equation, we get:
[tex]k=\frac{2.303}{9.0}\log\frac{60.0g}{7.5g}= 0.23days^{-1}[/tex]
To calculate the half life, we use the formula:
[tex]t_{1/2}=\frac{0.693}{k}[/tex]
[tex]t_{1/2}=\frac{0.693}{0.23}=3.02days[/tex]
