Answer:
Amount left = 9 g
Explanation:
Given data:
Half life of carbon-14 = 6000 years
Total amount = 72 g
Mass remain after 18000 years = ?
Solution:
Number of half lives = T elapsed / half life
Number of half lives = 18000 years / 6000 years
Number of half lives = 3
At time zero = 72 g
At first half life = 72 g/2 = 36 g
At second half life = 36 g/ 2= 18 g
At third half life = 18 g/2 = 9 g