🤓 Based on our data, we think this question is relevant for Professor McAbee's class at CSULB.
Barium-122 has a half-life of 2 minutes. You just obtained a sample weighing 10.0 grams. If takes 10 minutes to set up the experiment in which barium-122 will be used. How many grams of barium-122 will be left when you begin the experiment?
a. 0.313 g remain
b. 0.625 g remain
c. 0.00 g remain
d. 50.0 g remain
e. 2.00 g remain
We’re being asked to calculate the mass of barium-122 remaining from 10.0 g Ba-122 after 10 minutes. The half-life of Ba-122 is 2 minutes.
Since barium-122 has a half-life, it is a radioactive isotope. Recall that radioactive isotopes follow first-order kinetics.
The integrated rate law for a first-order reaction is as follows:
[A]t = concentration at time t
k = rate constant
t = time
[A]0 = initial concentration