2. An isotope of sodium 24N a has a half-life of 15 hours. A sample of this isotope has a mass of 2g. (a) Find the amount remaining after 60 hours.  (b) Find the amount remaining after t hours.  (c) Estimate the amount remaining after 4 days.  (d) Estimate the time required for the mass to be reduced to 0.01g

3. An ancient club is found that contains 150 g of pure carbon and has an activity of 4.5 decays per second. Determine its 14 C age assuming that in living trees the ratio of atoms is about 1.20 x 10-12. Note that the half life of carbon-14 is 12C 5700 years and the Avogadro number is 6.02 x 1023. years cei16 oct

5. A sample of protactinium -234 of mass 100 g has a half-life of G-7 hours. A. what praction of the sample has not decayed after 20-1 hours? B. What is the mass of undecayed protactinium -234 after this period of time...

3. The following graph shows the amount of mg for a radioactive substance. a. Determine the initial quantity of the material. b. Determine the half-life for this substance. 200 180 160 140 120 100 80 60 40 20 c. Determine the percent decrease per hour. d. Determine how long it will take for only 25 mg of the substance to remain. 10 (12,50) 15 20 25 30 W 35 40

4. I have two isotopes A and A' of an element with half-lives T/2 and Ti2 respectively. (a) Show that with time, the amount of A' relative to A is NA (t) f (t) = NA (t) = f (0) exp In (2) ( (b) The half-lives of 238U and 235U are 4.5 billion years and 700 million years, respectively. Natural uranium is currently about 97.3% 238U and 0.7% 235U. Based on the formula in (a), how long ago would you have been able to build an atomic bomb out of natural uranium ore, given that "weapons grade" uranium is at least 80% 235U? [MY]

4. What is the energy released/absorbed in this nuclear reaction 4N+H³C + 3He? (The atomic mass of 14 Nis 14.003074 u, and that of 1³C is 13.003355 u) MeV

6. One of the many isotopes used in cancer treatment is 798 Au, with a half-life of 2.70 d. Determine the mass of this isotope that is required to give an activity of 225 Ci. mg cer16 cei t would be

1. Determine the element created, and its atomic number and mass number when Lead-204 undergoes alpha decay, producing a stable isotope. Write the nuclear reaction equation for this alpha decay. lead 204 => 204 82 Pb

58. . Radiation treatment of prostate cancer. In many cases, BIO prostate cancer is treated by implanting 60 to 100 small seeds of radioactive material into the tumor. The energy released from the decays kills the tumor. One isotope that is used (there are others) is palladium (10°Pd), with a half-life of 17 days. If a typical grain contains 0.250 g of 10°Pd, (a) what is its initial activity rate in Bq, and (b) what is the rate 68 days later?

3. A 100kg sample of Neptunium 234 (Np234) was accidentally released due to the gross negligence of Jerf, the worst nuclear engineer ever. A. Jerf plans to act as though nothing happened until 95% of the sample has decayed into other elements. How long will they have to keep waffling about pretending to do experiments? (hint: Wikipedia knows the half-life of (Np234)) B. After two weeks, Jarrison, Jerf's supervisor, notices Jerf has had a minor decrease in productivity and decides to confront Jerf. Realizing their jig is up, Jerf decides to eat as much as they can before Jarrison notices. Assuming they eat 5 kgs of Np 234, how much is left for Jarrison to find? C. Following this incident, Jarrison, along with the EPA, makes a graph detailing the amount of Np 234 in Jerf's lab. Draw this graph and label all important events. Do not include the amount of Np234 that Jerf ingested, as a serendipitous genetic immunity to radiation Jerf inherited is the only reason they did not succumb to…