Answer:
initial amount = 800 mg
Step-by-step explanation:
Given data:
Amount of strontium-90 after 5 half life = 25 mg
Total amount of sample = ?
Solution:
At 5th half life = 25 mg
At 4th half life = 25× 2= 50 mg
At 3rd half life = 50×2 = 100 mg
At 2nd half life = 100×2 = 200 mg
At 1st half life = 200×2 = 400 mg
when time 0 = 400×2 = 800 mg
Conformation:
initial amount = 800 mg
1st half life = 800/2 = 400 mg
2nd half life = 400/2 = 200 mg
3rd half life = 200/2 = 100 mg
4th half life = 100/2 = 50 mg
5th half life = 50 /2 = 25 mg