The half-life of cobalt-60 is 5.3 yr. How much of a 1.000-mg sample of cobalt-60 is left after a 10.6yr
priod?
A) 0.250mg B) 0.100mg C) 0.990mg D) 0.125mg
2006-12-12 18:17:20 · 9 answers · asked by chem 1 in Science & Mathematics ➔ Chemistry
Half life means time it takes for the radioactive material to decay to half its original amount.
Co-60 half life is 5.3 yrs. so in 10.6 yrs = 2 half life.
so the amount left is after 1 half life = 1.000mg x 1/2 = 0.5 mg
amt left after 2 nd half life = 0.5mg x 1/2 = 0.250 mg
use this methods for all your half life calculatioons
2006-12-12 18:24:12 · answer #1 · answered by Matthew N 5 · 0⤊ 0⤋
Half Life Of Cobalt 60
2016-09-30 01:02:12 · answer #2 · answered by ? 4 · 0⤊ 0⤋
Correct answer is A. .500mg is left after 5.3 years (half) and after another 5.3 years (5.3+5.3=10) half again has decayed and 1/2 of .500mg is .125mg.
2006-12-12 18:24:36 · answer #3 · answered by Khushro G 1 · 0⤊ 0⤋
F) none of the above. do you own homework! thats the point so you can learn...or at least learn to think. wait to lie cheat and steal after school. even then u gotta be smart unless u want to get caught
2006-12-12 18:27:39 · answer #4 · answered by akihabro 2 · 0⤊ 1⤋
20(1/2)^10.52/5.26 =20(1/2)^2 = 5 years 20(1/2)^15.78/5.26 =20(1/2)^3 = 20/8 = 2.5 years
2016-03-29 05:27:24 · answer #5 · answered by ? 4 · 0⤊ 0⤋
A) 0.250mg
ln(Inital/Decay)
ln(1000/D)=kt
ln(1000/D)=(0.1308*10.6)
ln(1000/D)=1.386
e^1.386=4
4=1000/D
D=250
k=0.693(constant)/5.3(half-life)
=0.1308
As long as you understand.
2006-12-14 09:31:28 · answer #6 · answered by Sharona636 1 · 0⤊ 0⤋
.250grams 25%
10.6 yrs is two half lifes
.5 (half life) * 1.000gr = 0.500gr
.5(half life) * 0.500 = 0.250grams
2006-12-12 18:19:50 · answer #7 · answered by hockey 2 · 0⤊ 0⤋
a
2006-12-12 18:22:25 · answer #8 · answered by David B 6 · 0⤊ 0⤋
obviously, A. no calculation needed for something this simple!!!
2006-12-12 18:27:14 · answer #9 · answered by OneLilithHidesAnother 4 · 0⤊ 0⤋