Question

A certain radioactive nuclide has a half life of 74.8 years. How long does it take for 87.5% of a sample of this substance to decay?

___years?

Answer 1

In (SA) = kt a time t At initial concentration At concentration after k is rate constant K = 0.693 It is the half-life. InCA - INCA = kt Inca = - kt + InCA If we plot a graph (us) t we get a with a slope of Sk' intercept InCA of Inca straight line and

Remaining percent = 100-87.5 12.5 % 100 A = 12.5 CAO CA = 0.125 CAO CAO 0-693 Los conoscere ) = 0612x+ 0.125 (Ao 74.8 year in Cores) x 74.8 years 0.693 t=224.447658468 years