Question

The usefullness of radiocarbon dating is limited to objects no older than 50,000 yr. What percent of the carbon-14, orginally present in a 9.0-g sample, remains after this period of time?

The half-life of carbon-14 is 5.75 x 10³ yr.

= __________%

Answer 1

Given half life , T _1/2 = 5.75x10³ yr = 5750 yr

The decay constant ,

Calculation of mass of the sample left after time t :

For a first order reactions relation between time & masses is given by

                              

Where t = time taken = 50000 yr

N_o = initial mass of the sample = 9.0 g

N_t = mass of the sample left at time t = ?

Plug the values we get

                               

                                

                                 

                               

                               

Percentage of C-14 is =

So the percentage of C-14 is =0.24 %