Table of Contents
- 1 What has a half-life of 4.5 billion years?
- 2 How many uranium 235 235u half lives have occurred over the 4.5 billion year history of the earth?
- 3 What is the half-life of uranium?
- 4 What percentage of uranium-238 remains after two half-life?
- 5 Is uranium 235 rare?
- 6 What is the ratio of uranium-238 to lead 206?
What has a half-life of 4.5 billion years?
Uranium-238
Uranium-238 has a half-life of 4.5 billion years.
How many uranium 235 235u half lives have occurred over the 4.5 billion year history of the earth?
Number of half-lives passed = total time elapsed / length of a half-life.
| Element | Parent Isotope | Half-life |
|---|---|---|
| Carbon | C-14 | 5,730 years |
| Potassium | K-40 | 1.3 billion years |
| Uranium | U-238 | 4.5 billion years |
| U-235 | 710 million years |
How old is the rock if the half-life of uranium-238 is 4.5 billion years?
9 BY old
Since the half-life of U-238 is 4.5 Billion years, this rock must be 9 BY old.
What is the half-life of uranium?
about 4.5 billion years
The half-life of uranium-238 is about 4.5 billion years, uranium-235 about 700 million years, and uranium-234 about 25 thousand years.
What percentage of uranium-238 remains after two half-life?
Uranium-238
| General | |
|---|---|
| Neutrons | 146 |
| Nuclide data | |
| Natural abundance | 99.2745\% |
| Half-life | 4.468 billion years |
How old is a sample that contains a uranium 235 to lead-207 ratio of 1 7?
Remember, the half-life for Uranium-235 to Lead-207 is 700 million years. For something that is 4.6 billion years old, that means it would have passed through 6.7 half-lives. Let’s look at what that means for the ratio. One half life gives a ratio of ½ parent to ½ daughter or 1:1.
Is uranium 235 rare?
Nuclear power plants use a certain type of uranium—U-235—as fuel because its atoms are easily split apart. Although uranium is about 100 times more common than silver, U-235 is relatively rare at just over 0.7\% of natural uranium.
What is the ratio of uranium-238 to lead 206?
0.372
Answer and Explanation: The mass ratio of lead -206 to uranium-238 in the given rock is 0.372 .
Why is uranium half-life so long?
All the short half life isotopes have long time ago decayed and have disappeared. So only those isotopes that are either stable (Like Carbon-12) or have very long half lifes are still around. So the reason we still find Uranium (238 and 235) on earth today is thanks to their long half life.