Posted by Shay on .
It takes 1 hour and 17 min. for a 1.000gsample of a certain isotope to decay to 0.121g. What is the halflife of this isotope? plssss helpp

Science chemistry 
Scott,
if n is the number of halflives
(1/2)^n * 1.000 = 0.121
(1/2)^n = 0.121/1.000
n [log(1/2)] = log(0.121)
n = [log(0.121)] / [log(1/2)]
half life = [1h17m] / n