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Ch.5 Nuclear Chemistry
Timberlake - Chemistry: An Introduction to General, Organic, and Biological Chemistry 13th Edition
Timberlake13th EditionChemistry: An Introduction to General, Organic, and Biological ChemistryISBN: 9780134421353Not the one you use?Change textbook
Chapter 5, Problem 44

In another fission reaction, uranium-235 bombarded with a neutron produces strontium-94, another small nucleus, and three neutrons. Write the balanced nuclear equation for the fission reaction.

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1
Identify the reactants and products in the nuclear reaction. The reactants are uranium-235 (\( ^{235}_{92}U \)) and a neutron (\( ^{1}_{0}n \)). The products are strontium-94 (\( ^{94}_{38}Sr \)), another small nucleus (unknown for now), and three neutrons (\( 3 \times ^{1}_{0}n \)).
Apply the law of conservation of mass number. The total mass number (top number) of the reactants must equal the total mass number of the products. For the reactants, the mass number is \( 235 + 1 = 236 \). For the products, the mass number is \( 94 + x + 3 \times 1 \), where \( x \) is the mass number of the unknown nucleus.
Apply the law of conservation of atomic number. The total atomic number (bottom number) of the reactants must equal the total atomic number of the products. For the reactants, the atomic number is \( 92 + 0 = 92 \). For the products, the atomic number is \( 38 + y + 3 \times 0 \), where \( y \) is the atomic number of the unknown nucleus.
Solve for the unknown nucleus. Use the conservation laws to determine the mass number (\( x \)) and atomic number (\( y \)) of the unknown nucleus. Subtract the known values for strontium-94 and the neutrons from the total values of the reactants.
Write the balanced nuclear equation. Once the unknown nucleus is identified (e.g., \( ^{A}_{Z}X \)), combine all the components into the equation: \( ^{235}_{92}U + ^{1}_{0}n \rightarrow ^{94}_{38}Sr + ^{A}_{Z}X + 3 \times ^{1}_{0}n \).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Nuclear Fission

Nuclear fission is a process in which a heavy nucleus, such as uranium-235, splits into two smaller nuclei along with the release of energy and additional neutrons. This reaction can be initiated by the absorption of a neutron, leading to a chain reaction that is fundamental in nuclear reactors and atomic bombs.
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Balanced Nuclear Equation

A balanced nuclear equation represents a nuclear reaction in which the total number of protons and neutrons is conserved. Each side of the equation must have the same total atomic number and mass number, ensuring that the reaction adheres to the law of conservation of mass and charge.
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Products of Fission

In a fission reaction, the products typically include smaller nuclei, known as fission fragments, and free neutrons. For example, in the reaction mentioned, strontium-94 is one of the fission products, and the release of three neutrons can initiate further fission events, contributing to a self-sustaining chain reaction.
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