Question

How much phosphorus−32 remains from a 3.00 g sample after each of the following number of half-lives:

(a) 2;

(b) 8?

Answer 1

Half life by a sample amodent of a sample is defined as the time taken to reduce to its half of that of initial 0.09375 mole no. of moles of P-32 in 3.0gm nosz = 3.0g = 32 gmole we can give where Ao = initial amount A = amount left after n half life n= no. of half lifei if n=2 i.e. after a half life. 37 32 glmal o = 0.09375 mol = 0.02347 mole u Huy amount of P32 remained after a half life = 0.02347 mole 0.02347 mole 432 gimole P32 = 0.75 g o if n=8. l.e. after & half life A3 0.09375 mole = 3.66x1074 mole of Pzz = 3.66810-4 molex 32 gimole mass of 132 remained: 0.0117 g