ch. 19 nuclear chem                test                               40 points                                  honors chemistry

Show your work in an organized manner, include (i) any relevant equation (or formula), (ii) conversion factor(s), (iii) put the proper units in your calculations and answer, and (iv) have the proper number of significant figures in your answer.

Academic Honesty:   The answers on this test are my own and I am using only the allowed set of notes as described in the syllabus.  I have not discussed the test questions with anyone before or during the test nor have I seen the test questions prior to the exam.  If you violate any of the preceding items or do not sign, your semester grade is a F.

                                                                                                Signature:  ___________________

1. Write the nuclear reaction describing (hypothetical ?) ___  or fill-in the blank.  [10 points]

a.  Alpha decay of 140Ba:  _______________________________________

b.  Positron emission of 32P:  _______________________________

c. Neutron +  238U  →  2 neutrons  +  135Cs  +  ____ ; it’s an example of ________________  (name of type reaction)

d.  ____  +  17O  →  22Ne;  it’s an example of  _________________________ (name of type of reaction)

e. Beta decay of 14C:  ______________________________

2.  What is the meaning of the equation: E = m c2  ?   [5 points]

3. A hypothetical radioactive isotope has a half-life of 23 years; what is the value of its decay constant ?  [5 points]

4.  238U undergoes radioactive decay to form 234Th with a half life of 4.5 billion years.  A rock currently contains 25.0 mg 238U and 5.0 mg of 234Th.  What is the age of the rock ?  Assume that the rock originally had no 234Th.  [hint:  HW problem; 15 points]

5.  Briefly, describe the basis of the atomic bomb.  [5 points]