University:
High School
Course:
High School Physics
Academic year:

2022
Views:

332

Pages:

2
Author:

efreet4ifh37v

Unit 5 – Nuclear Chemistry – Quiz 1. Describe the mass, charge, actual identity, and relative penetration power of the following radioactive particles: a) Alpha particles - Helium atom, mass of 4, charge (atomic number) of 2, b) Beta particles - electron, no mass, -1 charge, 4 He, can be blocked by paper 2 0 e, can be blocked by wood −1 c) Gamma particles – energy (electromagnetic radiation), mass of 0, no charge, concrete 0 ɣ, can be blocked by 0 2. Compare and contrast fission and fusion. Fission – nuclei split into two parts. A neutron hits it, splits it, sending more neutrons out, to hit more atoms  tons of energy! Fusion – nuclei of atoms fuse together (example: sun).  way more energy, but not way to harness it or create it in a lab… yet The atomic bomb is an example of _fission__. The Hydrogen bomb is an example of __fusion___. 3. Write nuclear reactions for the following: a. Carbon-14 emits beta particles. 14 0 14 H e + N 6 −1 7 232 4 228 Th  2 He + 88 Ra 90 b. Thorium-232 goes through alpha decay. c. Radium-226 emits gamma and alpha particles. 226 222 4 0 Ra  86 Rn + 2 He + 0 ɣ 88 d. Chlorine-36 undergoes positron emission. 36 36 0 Cl  S + e 17 16 +1 e. Nitrogen-14 goes through electron capture. 14 0 N + e 7 −1 f. Argon-37 is produced by beta decay. 14  6 C 37 37 0 Cl  Ar + e 17 18 −1 g. Fermium-257 is formed by alpha and gamma emission. 261 257 4 0 No  Fm + He + ɣ 10 2 100 2 0 4. Fill in the blanks and identify the type of decay: 210 83 Bi  0 e + -1 210 84 Po Beta 234 91 Pa  0 e + +1 234 90 Th + 0 0 ɣ positron and gamma emission 5. Gold-191 has a half-life of 12.4 hours. What mass of this isotope would remain after 49.6 hours if you started with a 7.50 mg? 49.6/12.4 = 4 7.5  3.75  1.875  0.9375  0.469 mg 6. The half-life of cesium-137 is 30.2 years. If the initial mass of a sample of cesium-137 is 1.00 kg, how much will remain after 151 years? 151/30.2 = 5 half lives 1.00  0.5  0.25  0.125  0.0625  0.03125 kg 7. Given that the half-life of carbon-14 is 5730 years, consider a sample of fossilized wood that, when alive, would have contained 24 g of carbon-14. It now contains 1.5 g of carbon-14. How old is the sample? 24  12  6  3  1.5 4 half lives x 5730 = 22920 years 8. What is the half-life of an isotope of plutonium, if the original sample was 10 g and after 420 days there were 1.3 grams left? 10  5  2.5  1.25 (1.3) 3 half lives 420/3 = 140 days