Question

Sodium-24, t1/2 = 15.0 hr, can be used to study the sodium balance in animals. If a saline solution containing 25 μg of 24^Na is injected into an animal, how long can the study continue before only 1 μg is left?

Show work please!

Answer 1

k = 0.693/t_1/2
Then ln(No/N) = kt.
No = 25
N = 1
k from above.
t = solve for this.