Saturday
September 20, 2014

Homework Help: Chemistry

Posted by Nancy on Sunday, September 22, 2013 at 12:26am.

The half life of U238 is 4.5 x 10^9 yr. A sample of rock of 1.6 g produces 29 dis/sec. Assuming all radioactivity is due to U238 find percent by mass of U 238.

I have tried
ln(t)/ln(0)= -kt and still cannot get the answer
What I get is
A) 4.5x10^9 x365x60x60x24=1.419x10^17 for half life
B) .693/1.419x10^17=4.883x10-18

C) ln t/ln 29= -(4.883x10^-18)

That is the farthest I've gotten. Can someone help?

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

Chemistry please help! - A Cesium 137 sample has a measured radioactivity of 50 ...
Chemistry (Dr.Bob222) - The half-life of P-32 is 14 days. How long after a ...
math - An unknown radioactive element decays into non-radioactive substances. In...
chemistry - I have: the half life of U-238 is 4.5 x 10^9 yr. A sample of rock of...
Math - How long will it take for a 1 g sample of Polonium 210 to lose all but 1/...
Math - How long will it take for a 1 g sample of Polonium 210 to lose all but 1/...
Chemistry - I don't know if I should be posting this on a new session or just ...
Calculus-Modeling Equations - An unknown radioactive element decays into non-...
Chemistry - A rock containing 238U and 206Pb was examined to determine its ...
College Chemistry - A rock containing 238U and 206Pb was examined to determine ...

Search
Members