4. The remnants of an ancient fire in a cave in Africa showed a 'C decay rate of 3.9 counts per minute per gram of carbon. If the decay rate in C-14 in freshly cut wood, is 13.6 counts per minute per gram of carbon, how many years ago did the campfire occur? 5. A rock contains 0.257 mg of Pb-206 for every milligram of U-238.The half-life for the decay of U-238 to Pb-206 is 4.5 x 10°. How old is the rock?

4. The remnants of an ancient fire in a cave in Africa showed a 'C decay rate of 3.9 counts per minute per gram of carbon. If the decay rate in C-14 in freshly cut wood, is 13.6 counts per minute per gram of carbon, how many years ago did the campfire occur? 5. A rock contains 0.257 mg of Pb-206 for every milligram of U-238.The half-life for the decay of U-238 to Pb-206 is 4.5 x 10°. How old is the rock?

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...

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