3.) A 208 g sample of sodium-24 decays to 13.0 g of sodium-24 within 60.0 hours.

What is the half-life of this

radioactive isotope?

121 in

10 day how long will it take a 50.00 g sample t

Half life = 12 hrs

Explanation:

Given dа ta:

Total amount of sample = 208 g

Amount left after 60 hr = 13.0 g

Half life = ?

Solution:

Step one:

amount half life

208 g time 0

208/2 1 half life

104/2 2 half life

52/2 3 half life

26/2 4 half life

13 5 half life

Step 2:

half life = elapsed time / total half life when 13 g is left

Half life = 60 hrs / 5

Half life = 12 hrs