Problem: The half-life of 238U is 4.5 x 109 yr. A sample of rock of mass 1.7 g is found to produce 30 dis/s. Assuming all the radioactivity is due to 238U, find the percent by mass of 238U in the rock.

FREE Expert Solution

Step 1

4.5×109 yr ×365 d1 yr×24 hr1 d×60 min1 hr×60 s1 min = 1.4191x1017 s

  

Step 2

t12 = ln 2kk = ln 2t12k = 0.6931.4191×1017 s

k = 4.8843x10-18 s-1


View Complete Written Solution
Problem Details

The half-life of 238U is 4.5 x 109 yr. A sample of rock of mass 1.7 g is found to produce 30 dis/s. Assuming all the radioactivity is due to 238U, find the percent by mass of 238U in the rock.

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the First Order Half Life concept. You can view video lessons to learn First Order Half Life. Or if you need more First Order Half Life practice, you can also practice First Order Half Life practice problems.