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Science 10: 7.3 Nuclear Reactions

Text: Chapter 7, pages 312-325

Part A: Nuclear Reactions Overview

-What is the difference between nuclear fission and nuclear fusion?

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Part B: Nuclear Fission

-Why do you think large, heavy nuclei might split apart?

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-What are some of the positives and negatives of Nuclear Fission?

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Part C: Nuclear Reactions vs. Chemical Reactions

-Examine the chemical reaction above. What are some general principles you can draw from it?

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-How are nuclear reactions different from normal chemical reactions?

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Part C: Nuclear Equations for Induced Nuclear Reactions

-What three types of radiation can potentially be released by natural radioactive decay?

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-Scientists can actually cause the radioactive decay of a nuclear by making it unstable. What is different about the reaction below from the natural radioactive decay we explored in 7.1?

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-The induced nuclear reaction can be written in two ways:

-There are a couple of rules for writing nuclear equations:

1. The sum of the mass numbers on each side of the equation stays the same.

2. The sum of the charges on each side of the equation stays the same.

*Complete Reading Check on page 315.

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Part D: Nuclear Fission of Uranium-235

-Examine the diagram below. Why do you think that it is easier for a neutron to be crashed into Uranium-235 than an alpha particle into Nitrogen-14 (as depicted on the previous page)?

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-Why does only the mass number of uranium change and not the atomic number?

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-Are both sides of the equation equal?

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-The nuclear fission of U-235 the reaction that occurs inside of nuclear power plants and nuclear weapons.

*Complete the Practice Problems on page 317.

Part E: Chain Reactions

-What do you think happens to the three neutrons produced by this decay of U-236?

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-Chain reactions can quickly get out of control, but this danger is managed in nuclear reactors by using materials that absorb neutrons.

-Canada’s CANDU reactors are amongst the safest in the world and produce energy by the nuclear fission of U-235.

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-Used U-235 rods can be hazardous to get rid of as they continue to be radioactive for twenty half-lives (thousands of years). Some rods can be re-used, but others must be stored sealed inside concrete or metal containers underground.

Part F: Nuclear Fusion

-Examine the diagram right. What is nuclear fusion?

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-Nuclear fusion occurs in stars, like our Sun. Why do you think scientists have not been able to successfully re-create this reaction?

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*Complete Check Your Understanding 1-11 on page 325.

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