4. Positron sources are used in PET scans (PET = positron emission tomography), which are an important part of medical imaging used in diagnosis. One isotope used in PET scans is carbon-11, which decays as shown here: 5 11 6 11 ₁₁ Ce+₁ B Recall that during beta emission, a neutron decays into a proton. Based on the decay equation for ₁₁ C, what change must be happening within the nucleus during positron emission? (-1 pts) Incorrect. (0/1pts) 5. A tiny percent of all naturally-occurring carbon atoms on Earth are carbon-14. Trees (and all living things) incorporate C-14 into their bodies when alive, but this ceases at death, after which the amount of C-14 present gradually decreases due to nuclear decay. Wooden artifacts from long ago can be dated by the percent of carbon-14 remaining in them. A sample of a wooden object from an archaeological site contains only 12.5% of the level of carbon-14 expected for a live tree. How many half-lives have passed since that piece of wood was a living tree? (-1 pts) Incorrect. (0/1pts) 6. Approximately how much time has passed since that piece of wood was a living tree? (See Table NU.3. in the lab manual) (-1 pts) Incorrect. Choose... Choose... Choose... Report Table NU.3: Time Data Effect of time on measured counts per minute Source Item used Counts at 1 minute Counts at 2 minutes Counts at 5 minutes fiesta-ware plate 164 321 886

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

See similar textbooks

Related questions

Question

4. Positron sources are used in PET scans (PET = positron emission tomography), which are an important part of medical imaging used in diagnosis. One isotope used in PET scans is carbon-11, which decays as shown here:

611C⟶10e+511B116C⟶01e+115B

Recall that during beta emission, a neutron decays into a proton. Based on the decay equation for 611C116C, what change must be happening within the nucleus during positron emission?

5. A tiny percent of all naturally-occurring carbon atoms on Earth are carbon-14. Trees (and all living things) incorporate C-14 into their bodies when alive, but this ceases at death, after which the amount of C-14 present gradually decreases due to nuclear decay. Wooden artifacts from long ago can be dated by the percent of carbon-14 remaining in them. A sample of a wooden object from an archaeological site contains only 12.5% of the level of carbon-14 expected for a live tree. How many half-lives have passed since that piece of wood was a living tree?

6. Approximately how much time has passed since that piece of wood was a living tree? (See Table NU.3. in the lab manual)