Question

A radioactive tracer has a half-life of two hours how much of a 2500 g sample will be available after 18 hours?

Answer 1

ANSWER:

4.88 grams

STEP-BY-STEP EXPLANATION:

We must first calculate how many half-life there are in 18 hours, knowing that each half-life takes 2 hours.

$\frac{18}{2}=9\text{ half-life}$

Now, knowing this, we can calculate the number of grams applying 9 times the half-life, like this:

$\frac{2500}{2^9}=4.88\text{ g}$

Which means that after 18 hours there are 4.88 grams