Answer:
66.7s
Explanation:
Let's bring out the parameters we were given...
Half life = ?
Initial Concentration = 0.0576 M
Final Concentration = 0.0249 M
Time for the concentration change to occur = 97.8s - 17.1s = 80.7s
Formular for half life (t1/2) is given as;
t1/2 = ln2 / k ≈ 0.693 / k
where k = rate constant
From the formular of first order reactions;
ln[A] = ln[A]o − kt
where [A] = Final Concentration and [A]o = Initial Concentration
Inserting the values, we have;
ln(0.0249) = ln(0.0576) - k(80.7)
Upon solving for k, we have;
-0.8387 = -k(80.7)
k = 0.01039 s−1
t1/2 = 0.693 / k = 0.693 / 0.01039 = 66.7s
