A patient recieves 9.0 ng of a radioisotope with a half-live of 12 hours. How much will remain in the body (in ng) after 2.0 days?

1 Answer
Nov 23, 2017

Answer:

Approximately #0.563ng# of the described radioisotope will remain in two days within the patient's body.

Explanation:

#ln(([A]_t)/([A]_0)) = -kt#

#t_(1/2) = 0.693/k#

#-----#

#12h = 0.693/k#
#therefore k approx 5.78*10^-2h^-1#

#ln(([A]_(2d))/(9.0ng)) = -5.78*10^-2h^-1 * 2.0d * (24h)/(d)#
#therefore [A]_(2d) approx 0.563ng #