Answer to Question #163991 in General Chemistry for koo

Question

1. How do nuclear reactions differ from ordinary chemical reactions?

2. State the general rules for predicting nuclear stability.

3. Outline the principle for dating materials using radioactive isotopes.

4. What is the difference between radioactive decay and nuclear transmutation?

5. In nuclear fission, explain how an atomic bomb works.

6. Why do heavy elements such as uranium undergo fission while light elements such as

hydrogen and lithium undergo fusion?

7. What are the advantages of a fusion reactor over a fission reactor? What are the

practical difficulties in operating large-scale fusion reactor?

Answer 1

(1) Nuclear reactions involve a change in an atom's nucleus, usually producing a different element. Chemical reactions, on the other hand, involve only a rearrangement of electrons and do not involve changes in the nuclei.

2)A general rule is there is approximately equal numbers of neutrons and protons, but as you go to larger masses, you require more neutrons than protons for stability. Nuclear stability is governed by a combination of quantum mechanical rules, nuclear forces, and electrostatic charge.

3)The energies involved are so large, and the nucleus is so small that physical conditions in the Earth (i.e. T and P) cannot affect the rate of decay. The rate of decay or rate of change of the number N of particles is proportional to the number present at any time.

4)Nuclear decay reactions occur spontaneously under all conditions and produce more stable daughter nuclei, whereas nuclear transmutation reactions are induced and form a product nucleus that is more massive than the starting material.

5)Nuclear fission produces the atomic bomb, a weapon of mass destruction that uses power released by the splitting of atomic nuclei. When a single free neutron strikes the nucleus of an atom of radioactive material like uranium or plutonium, it knocks two or three more neutrons free.

7)In a nuclear decay reaction, also called radioactive decay, an unstable nucleus emits radiation and is transformed into the nucleus of one or more other elements. The resulting daughter nuclei have a lower mass and are lower in energy (more stable) than the parent nucleus that decayed.