Wednesday

September 17, 2014

September 17, 2014

Posted by **Jen** on Wednesday, February 14, 2007 at 9:39am.

a)Find a function that models the mass remaining after t years.

b)How much of the sample will remain after 80 years?

c)After how long will only 2 g of the sample remain?

Thanks

(a) M(t) = mass of Cesium-137 at time t, in years = Mo* 2^(-t/30)

Mo is the initial mass of 10 g.

2^(-t/30) means 2 to the -t/30 power

(b) Plug in t = 80 and see that you get for M

(c) Set M = 2 and see what you get for t. Hint: take logs of both sides of:

2 = 10 * 2^(-t/30)

(0.2) = 2^(-t/30)

**Answer this Question**

**Related Questions**

algebra - Suppose a sample of Cesium-137 with initial mass of 200 grams decays ...

chem - Cesium-137 has a half life of 30.0 years. If initially there are 8.0 kg ...

Chemistry please help! - A Cesium 137 sample has a measured radioactivity of 50 ...

Chemistry/math - Cesium-137 has a half-life of 30 years. Suppose a lab stored a ...

Chemistry - Which radioactive sample would contain the greatest remaining mass ...

Calculuc - How do you set up this problem? The decay constant for the ...

calculus - The rate at which an amount of a radioactive substance decays is ...

math - how to compute this problem? a certain element has a half life of 12 ...

Chem 3A - please help me with this chemistry problem. Half-Life A radium-226 ...

chemistry - What percent of the original sample of strontium-90 (half-life = 28....