1. Write nuclear equations to show the disintegration of the first six radioactive isotopes listed in Table 26-1.

2. The following isotopes are artificially radioactive. They emit the particles shown in parentheses. Write nuclear equations to show the disintegration of these isotopes.(a) (d)

(b) (e)

(c)

3. Bombardment reactions are often summarized in a terse form, such as . This

means that the target is bombarded by a particles , and that neutrons ( ) are

produced. By the rules for balancing nuclear equations, we know that also is produced. Give the complete balanced nuclear equation for each of the following transmutation bombardments (p stands for proton, and d stands for deuteron in this notation).(a) (d)

(b) (e)

(c)

4. (a) Calculate the energy liberated per mole of lithium when the following reaction takes place:

The actual mole weights involved are = 7.01818 g; = 1.00813 g; = 4.00386 g.

(b) How many tons of carbon would have to be burned to give as much energy as 100 g of consumed by this reaction? (Carbon gives 94. 1 kcal/mole when burned to CO2.)

5. The halogen astatine can be obtained only by artificial methods through bombardment. It has been found useful for the treatment of certain types of cancer of the thyroid gland, for it migrates to this gland just as iodine does. If a sample containing 0.1 mg of is

given to a person at 9 A.M. one morning, how much will remain in the body at 9 A.M. the following morning?

6. A purified sample of a radioactive compound is found to have 1365 cpm at 10 A.M., but only 832 cpm at 1 P.M. the same day. What is the half-life of this sample?

7. If in the explosion of one atom bomb 50.0 g of were scattered about in the atmosphere before it had a chance to undergo nuclear fission, how much would be left in the atmosphere after 1000 yrs? (Assume that none of it settles out )

8. If you seal a 100 g sample of very pure uranium in a container for safekeeping, and if in the distant future a scientist dissolves it and finds it to contain 0 800 g - , how many years have elapsed since you sealed the sample? (Lead is the stable endproduct of the radioactive decay of uranium)

9 .Willard Libby and colleagues have found that a very small amount of the CO2 in the air is radioactive, as a result of continuous bombardment of nitrogen in the upper atmosphere by neutrons of cosmic origin This radioactive is uniformly distributed among all forms of carbon that are in equilibrium with the atmosphere, and it is found to show 153 cpm/gram of carbon All plants use CO2 for growth, and while living are in equilibrium with the atmosphere When plants die, they no longer remain in equilibrium with the air, and the carbon slowly loses its activity Cyprus wood from the ancient Egyptian tomb ofSneferu at Meydum has an activity of 6 88 cpm/g of carbon Estimate the age of this wood (and presumably the age of the tomb)

10. A 0 500 g sample of is sealed into a very thin-walled tube, so that the particles emitted from the radium and its decay products can penetrate and be collected in an evacuated volume of 25 0 ml What helium pressure at 20 0°C will build up in 100 yrs? (Five a particles are produced as radium disintegrates to a stable isotope of lead)

11. Radioactive sulfur has been used as a tracer in the study of the action of sulfur as an insecticide for red spider (a citrus-fruit pest). If 10.0 mg of if are absorbed by an orange, how much will remain after 6.00 months in storage?

12. A 100 ml sample of a 0.0100 M Ba(NO3)2 solution is mixed with 100 ml of a 0.0100 M Na2SO4 solution that has been labeled with ? and that has 25,000 cpm/ml of solution. After precipitation, the supernatant liquid is filtered off, and it is found that 1.00 ml of solution now has only 26.0 cpm (corrected for background). From these data, calculate the solubility product for BaSO4.