Baird Chem in Your Life Chapter 17

Baird Chem in Your life Chapter 17

1. What particles in an atom cause the same element to become an isotope? a. neutrons b. protons c. electrons d. photons a: Isotopes differ because of their mass numbers. If an isotope is the same element (same protons), then the neutrons are different.

2. What particle is released during beta emission? a. electron b. proton c. neutron d. photon a: Beta is defined as an electron on page 627.

3. When an isotope of lead (Pb-214) decays and releases a beta particle, what new particle forms? a. Pb-214 b. Bi-213 c. Bi-215 d. Tl-214 a: A beta particle is an electron that has an atomic number of −1 and 0 amu; therefore, it forms a particle with an atomic number of 83 and a mass number that stays the same.

4. What form of radiation is released when Th-232 forms Ra-228? a. alpha particle b. beta particle c. gamma radiation d. X-rays a: An alpha particle is an He-4 isotope; therefore, Th has an atomic number of 90 and forms Ra which has an atomic number of 88.

5. What particle forms when the isotope Bi-210 releases a beta particle? a. Po-210 b. Po-211 c. Pb-210 d. Pb-211 a: When Bi-210 loses a beta particle, an isotope of Po forms with a mass number of 210.

6. What isotope produces radon gas through disintegration? a. U-238 b. Th-234 c. Ra-226 d. Pb-206 a: See page 632 for the nuclear reactions that form radon gas.

7. If the half-life of radon is 3.8 days, what amount of a 20-gram sample of radioactive radon is left after 7.6 days? a. 5 grams b. 10 grams c. 15 grams d. none is left a: 7.6/3.8 = 2 half-life changes; therefore, a start amount of 20 grams will leave 10 grams during the first half-life change and 5 grams for the second half-life change.

8. How much I-131 has decayed after 32 days of a 90-gram sample if the half-life is 8 days? a. 75 g b. 70 g c. 60 g d. 80 g a: 32/8 = 4 half-life changes; therefore, 5 grams is still unstable. Subtract 5 grams from the original 80 grams, which equals 75 grams decayed.

9. What subatomic particle is required for fission to occur? a. neutron b. proton c. electron d. alpha particle a: This is described on page 635.

10. What isotope is usually used in fission reactors to produce energy? a. U-235 b. U-238 c. Pu-244 d. Ra-226 a: This is described on page 636.

11. What radioactive by-product is produced by the operation of nuclear power reactors? a. U-235 b. U-239 c. Np-239 d. Pu-239 a: This is described on page 637.

12. What country generates the largest proportion of electrical energy by nuclear power? a. France b. Japan c. United States d. Russia a: Table 17.1 on page 636 lists the countries that use nuclear power.

13. What isotopic element has the greatest potential as a producer of useful commercial energy? a. hydrogen b. helium c. lithium d. radium a: Hydrogen isotopes of deuterium and tritium are used for fusion reactors.

14. Which of the following is not a form of solar energy that can be transferred for commercial use? a. fuel cells b. wind power c. solar cells d. hydroelectric a: Fuel cells are chemical cells that have nothing to do with solar energy.

15. What materials are used for photovoltaic cells that produce electricity directly from sunlight? a. semiconductors b. conductors c. metals d. insulators a: Semiconductors are used in photovoltaic cells, as described on page 653.