In: Chemistry
Rubidium-87 decays by β production to strontium-87 with a half life of 4.7 × 1010 years. What is the age of a rock sample that contains 105.9 µg 87Rb and 7.9 µg 87Sr ?
____ years old
Assume that no 87Sr was present when the rock was
formed.
The atomic masses are given in the table below:
| Nuclide | Atomic Mass | 
| 87Rb | 86.90919 | 
| 87Sr | 86.90888 |