# Working with a radiactive material

Not what you're looking for? Search our solutions OR ask your own Custom question.

The half life of Cl is 9.5 x 10(exponent 12)s. How many atoms of Cl are present in a sample with an activity of 1.5 x 10(exponent 9) atoms/s

a. 2.1 x 10(exponent 22) atoms

b. 6.3 x 10(exponent 3) atoms

c. 4.9 x 10(exponent negative 23) atoms

d. 1.4 x 10(exponent 22) atoms

e. 7.0 x 10(exponent 23) atoms

https://brainmass.com/chemistry/inorganic-chemistry/working-radioactive-material-7573

## SOLUTION This solution is **FREE** courtesy of BrainMass!

Half life t_1/2 = 9.5 x 10^12 s

means, in this time, the radioactive material will have reduced to half its original quantity.

Given activity is A = 1.5 x 10^9 atoms/second

WE WILL NOW FIND THE DECAY CONSTANT LAMDA (L)

L = 0.693/t_1/2

= 0.693/9.5 x 10^12 s = 0.073x10^-12 /Second

Activity A = L N

where N is the number of atoms

Now N = A/L = 1.5 x 10^9/0.073x10^-12

= 20.55 x 10^21

approximately, the answer is 2.1 x 10^22 atoms

Answer(A)

Â© BrainMass Inc. brainmass.com October 5, 2022, 3:03 pm ad1c9bdddf>https://brainmass.com/chemistry/inorganic-chemistry/working-radioactive-material-7573