Question

Iodine-131 has a half-life of 8 days. How much would be left of an original 40 g sample after 40 days?

Answer 1

Answer:

d) 1.25 g

Step-by-step explanation:

If it has a half life of 40 days, there will be 5 half-lives in that span of time so if you divide 40 by 2, 5 times or just $\frac{40}{2^{5} }$, it will equal 1.25.

$\frac{40}{2}=20$

$\frac{20}{2} =10$

$\frac{10}{2} =5$

$\frac{5}{2} =2.5$

$\frac{2.5}{2} =1.25$