# Problem: 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?

🤓 Based on our data, we think this question is relevant for Professor Hassell's class at BAYLOR.

###### FREE Expert Solution

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: where:

[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:  ###### Problem Details

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? 