<u>Answer:</u> The age of the mineral sample is
<u>Explanation:</u>
The equation used to calculate rate constant from given half life for first order kinetics:
where,
= half life of the reaction =
Putting values in above equation, we get:
We are given:
Mass ratio of K-40 to Ar-40 = 0.812 : 1.00
Rate law expression for first order kinetics is given by the equation:
where,
k = rate constant =
t = time taken for decay process = ? yr
= initial amount of the sample = [1.00 + 0.812] = 1.812 grams
[A] = amount left after decay process = 1.00 grams
Putting values in above equation, we get:
Hence, the age of the mineral sample is