Question

A sample of Carbon-14 originally contained 100 g. After three half-lives have

passed, how much Carbon-14 is left?

Answer 1

After 3 half lives 12.5 g of C-14 left

Step-by-step explanation:

Given data:

Mass of C-14 = 100 g

After 3 half lives mass left = ?

Solution:

At time zero = 100 g

At first half life = 100 g/2 = 50 g

At second half life = 50 g/ 2 = 25 g

At third half life = 25 g/2 = 12.5 g

Thus, after 3 half lives 12.5 g of C-14 left.