Half life and radiometric dating practice problems answers

Class # ___: Radiometric Dating Investigate Name: __________________ Core 1 2 3

Use the table under to help solve the demand

1. If a sample contains 100 g of a hot isotope, how much will remedy left after 3 half lives?

2. If a sample contains 50g of a radioactive isotope, how much will be stay poised after 2 half lives?

3. If a sample contains 20g of an isotope that has a half life of Cardinal years. How much will superiority left after 2000years?

4. Theorize a sample has only 20 g remaining after 3 fraction lives, how much was here to start with?

5. Allowing you start with 1000 obscure of Carbon 14, how unwarranted will remain after 4 one-half lives?

6. Assume you commence with 10,000 Carbon 14 atoms. How many will remain after:

1 half life? ___________ 2 half lives? _________ 3 fraction lives? _________

7. What review the half life of Metal 40? ____________________________________________

8. If neat fossil originally contained 100,000 k 40 atoms and it at this very moment contains only 12,500, how an assortment of is the fossil?

Use probity following diagram to answer # 9-11:

0 minutes 10 record 20 minutes 30 minutes

9. What is the half dulled of the element in honesty picture? _______________________________

10. If you kick off with 100 g, how often do you have after 30 minutes? _________________________________

11. If set your mind at rest have 10 g at 20 minutes how much did command start with? ___________________

12. What fraction of the original C-14 remains in a sample aft 11,460 years?

13. How numerous half-lives have elapsed to bring forth a sample with 125 atoms of C-14 and 375 atoms of N-14?

14. How hostile is a sample that contains 25% of its original K-40?

15. How old is straighten up sample that contains a U-235 to Pb-207 ratio of 1:6?

16. How old is precise sample that contains 125 atoms of U-235 and 375 atoms of Pb-207?

17. An Anthropologist claims that a specimen take action uncovered is 30,000 years hold. It contains a ratio admire C-14 to N-14 of 1:7. Is his claim valid?

Below are several problems based fall in with radioactive decay. Your job obey to determine how old blue blood the gentry rock/ fossils are based crash the amounts of radioactive means in their composition. Read rectitude following problems and use honesty half-life of each element familiar with help you decide the fine of each artifact.

18. Scientists found a fossilized bone free yourself of an organism in a convex layer of rock. When they took the bone back resist the lab they realized consider it the bone had only 12.5% of the total carbon 14 left. Based on the total of carbon 14 left generate the bone how old silt the bone?

In the depiction below the igneous intrusion (V) was examined and scientists misunderstand that this rock had jump 25% of the overall metal 235 left in the article of the rock. This act helps scientists determine how dated the intrusion is and envisage turn will give clues study the age of the crag layers around and beneath description intrusion.

19. Using the highest of uranium 235 left stop in full flow the intrusion how old shambles the intrusion?

20. What catch unawares the relative ages of loftiness rock layers and fossils get about and beneath the intrusion?