Homework Help: Gen Chem

Posted by Sarah H on Friday, March 28, 2008 at 5:34pm.

Neptunium-239 has a half-life of 2.35 days. How many days must elapse for a sample of 239-Np to decay to 1.00% of its original quantity?

I got: close to 15 days. Is this right?
I figured that about 1% of the original quantity would be roughly 6.5 Half lives, and since a half life is 2.35 days, 6.58*2.35

Gen Chem - DrBob222, Friday, March 28, 2008 at 5:52pm
It's done this way for an exact answer.
k = 0.693/t_1/2. Substitute k into the following equation and solve for t.
ln(100/1) = kt.
I get 15.6 days.

Answer this Question

Related Questions

CHEM - Pu-239 has a half-life of 24110 y. If 1.00 kg of this isotope is present ...
CHEMISTRY - Suppose you had a detection device that could count every decay ...
Math - _The_Natural_Base_e_ An accident in 1986 at the Chernobyl nuculear plant ...
chemistry - The half-life for the radioactive decay of calcium-47 is 4.5 days.If...
Math with science - Radioactive iodine treatment is so successful at treating ...
calculus - Question: "Plutonium isotope Pu-239 has a half-life of 24,100 ...
Chemistry - How much a 2.00 g 239 Pu would have decayed after 1.6 x 10^4 years? ...
half-life of radioisotope - A radioisotope has a half-life of 4 days. How much ...
college chem - S-35 (t1/2 = 87.4 d) is used in cancer research. The biological ...
math - The half life of iodine - 131 is 8 days. How long will it take for 7/8 of...

For Further Reading

First Name:
School Subject:
Answer: