Asked by Cyn
The half-life of sodium-24 is 14.9 hours. A hospital buys a 40 mg sample of sodium-24.
a) How many grams, to the nearest tenth, of sodium-21 will remain after 48 h?
b) After how long will only 2.5 mg remain?
I don't know how to write the exponential function in order to be able to solve this. ><
a) How many grams, to the nearest tenth, of sodium-21 will remain after 48 h?
b) After how long will only 2.5 mg remain?
I don't know how to write the exponential function in order to be able to solve this. ><
Answers
Answered by
Reiny
amount = 40(1/2)^(t/14.9) , where t is the number of hours.
test: if t = 0, Amount = 40 , Check!
if t = 14.9
amount = 40(1/2)^1 = 20 , Check!
a) if t = 48
Amount = 40(1/2)^(48/14.9)
= 40(1/2)^3.22147651
= 40(.107210899)
= appr. 4.29 g
b) 2.5 = 40(1/2)^(t/14.9)
.0625 = (.5)^(t/14.9)
t/14.9 = ln.0625/ln.5
t/14.9 = 4
t = 4(14.9) = 59.6 hours
test: if t = 0, Amount = 40 , Check!
if t = 14.9
amount = 40(1/2)^1 = 20 , Check!
a) if t = 48
Amount = 40(1/2)^(48/14.9)
= 40(1/2)^3.22147651
= 40(.107210899)
= appr. 4.29 g
b) 2.5 = 40(1/2)^(t/14.9)
.0625 = (.5)^(t/14.9)
t/14.9 = ln.0625/ln.5
t/14.9 = 4
t = 4(14.9) = 59.6 hours
There are no AI answers yet. The ability to request AI answers is coming soon!
Submit Your Answer
We prioritize human answers over AI answers.
If you are human, and you can answer this question, please submit your answer.