Chemistry Test Nuclear Chemistry 2 — Questions and Answers
Question 1: What is nuclear fusion?
- Splitting a uranium nucleus
- Combining two light nuclei to form a heavier nucleus (Correct answer)
- Emitting gamma radiation from an excited nucleus
- Capturing an electron by the nucleus
Correct answer: Combining two light nuclei to form a heavier nucleus
Nuclear fusion combines two light nuclei (e.g., hydrogen isotopes) into a heavier nucleus, releasing enormous amounts of energy — the process that powers the sun.
Question 2: Which equation expresses Einstein's mass-energy equivalence relevant to nuclear reactions?
- E = hν
- E = mc² (Correct answer)
- E = ½mv²
- E = kT
Correct answer: E = mc²
Einstein's E = mc² shows that the mass defect in a nuclear reaction corresponds to the energy released, with c being the speed of light.
Question 3: Carbon-14 dating is based on the radioactive decay of ¹⁴C with a half-life of approximately 5,730 years. If a sample has 25% of its original ¹⁴C remaining, how old is it?
- 5,730 years
- 11,460 years (Correct answer)
- 17,190 years
- 22,920 years
Correct answer: 11,460 years
After one half-life (5,730 yr) 50% remains; after two half-lives (11,460 yr) 25% remains, so the sample is ~11,460 years old.
Question 4: What is a chain reaction in nuclear fission?
- A series of fusion events
- Neutrons from one fission event triggering additional fissions (Correct answer)
- Sequential alpha decay events
- A reaction requiring a catalyst
Correct answer: Neutrons from one fission event triggering additional fissions
In a chain reaction, neutrons released by one fission event strike other fissile nuclei, causing more fissions and releasing more neutrons in a self-sustaining process.
Question 5: Which term describes the energy required to completely separate a nucleus into its individual protons and neutrons?
- Ionization energy
- Activation energy
- Binding energy (Correct answer)
- Lattice energy
Correct answer: Binding energy
Nuclear binding energy is the energy needed to disassemble a nucleus into its constituent protons and neutrons; it reflects the stability of the nucleus.
Question 6: What type of radiation is stopped most easily (e.g., by a sheet of paper)?
- Gamma (γ)
- Beta (β)
- X-rays
- Alpha (α) (Correct answer)
Correct answer: Alpha (α)
Alpha particles are the largest and most massive radiation type, so they have the least penetrating power and are stopped by just a sheet of paper or a few centimeters of air.
Chemistry Test Nuclear Chemistry 2
What is nuclear fusion?