🤓 Based on our data, we think this question is relevant for Professor Hassell's class at BAYLOR.
We’re being asked to determine the mass of arsenic–74 remaining after 54 days if there are 2.3 mCi (millicurie) of 74As initially.
Recall that radioactive/nuclear decay of isotopes follows first-order kinetics, and the integrated rate law for first-order reactions is:
[N]t = concentration at time t
k = decay constant
t = time
[N]0 = initial concentration.
Also, recall that half-life is the time needed for the amount of a reactant to decrease by 50% or one-half.
The half-life of a first-order reaction is given by:
The half-lives of different medical radioisotopes are given in the table below. If the initial amount of arsenic-74 is 2.3 mCi, how much arsenic-74 (mCi) is left in the body after 54 days?