Phosphorus-32 is a radioactive isotope used as a tracer in the liver. How much phosphorus-32 was originally used if there is only 3.50 mg left in a sample after 288 h? (Th half-life of phosphorus-32 is 14.3 days.) * . 1.

26) Iodine-131 is one of the many radioactive isotopes resulting from nuclear bomb explosions. If a sample initially has 2.50 mg, how much will remain after 12.0 days? The half-life of iodine-131 is 8.02 days. (SHOW CALCULATIONS)

Radioactive vanadium-48 decays with a half-life of 16.0 days. a. What is the value of k in s? k = b. A sample contains 84.0 mg *°V. How many decay events will be produced in the first second? Assume the atomic mass of **V is 48.0 u. decays/s c. A chemist obtains a fresh sample of 48 V and measures its radioactivity. She then determines that to do an experiment, the radioactivity cannot fall below 25% of the initial measured value. How long does she have to do the experiment? days

The half-life of 14C is 5730 years, and the current decay rate in living organisms is 14.3 disintegrations per minute per gram of carbon (d.p.m./g C). What is the age (in years BP) of an artifact found to have a decay rate of 4.75 d.p.m/g C in 2013? IMPORTANT: When entering your answer: • Enter the number only (no units) • Do not leave any spaces • Report your number to the tens column (regardless of the significant figures) Correctly round your answer to the tens column (margin of allowed error is only ± 10, so always use un-rounded numbers in your calculations) Examples: 12340 or 5670 (include the zero in the units column, Canvas will add a comma for you)