Question

32P is a radioactive isotope with a half-life of 14.3 days. If you currently have 89.5 g of 32P, how much 32P was present 8.00 days ago?

Answer 1

Decay constant ,

Where T_1/2 = half life = 14.3 days

So decay constant ,

We know that

Where N_o = initial mass = 89.5 g

          N_t = mass after time t = ?

         t = time taken = 8.00 days

Plug the values we get

                                   

                                

Therefore the mass of 32P left after 8.00 days is 60.7 g