Homework Help: Chemistry please help!

Posted by Mary on Saturday, February 9, 2008 at 7:49pm.

A Cesium 137 sample has a measured radioactivity of 50 microcuries.Cesium 137 has a half-life of 30 years.

How long will it take this sample to be reduced to a residual radioactivity of 6.25 microcuries?

Is there a formula to calculate half life?

Chemistry please help! - DrBob222, Saturday, February 9, 2008 at 9:01pm
k = 0.693/t_1/2

Then ln(No/N) = kt
No = 50 microcuries
N = 6.25 microcuries
k from above (t1/2 = 30 years).
t = solve for this.

Answer this Question

Related Questions

chem - Cesium-137 has a half life of 30.0 years. If initially there are 8.0 kg ...
algebra - Suppose a sample of Cesium-137 with initial mass of 200 grams decays ...
word problem - The half life of cesium-137 is 30 years. Suppose we have a 10-g ...
Chemistry/math - Cesium-137 has a half-life of 30 years. Suppose a lab stored a ...
Calculuc - How do you set up this problem? The decay constant for the ...
chemistry - How long will it take for the 100mg of cesium-137 to decay to 6.25mg...
chemistry - The isotype caesium -137, which has a half life of 30 years, is a ...
Chemistry - The isotope caesium-137, which has a half life of 30 years, is a ...
Nuclear Physics - An investigator receives Co-60 (5.27 year half life) for use ...
Science economic - Cesium 138 has a half life equal to 32.2 minutes. how long ...

For Further Reading

First Name:
School Subject:
Answer: