Textbook Question
The atomic masses of hydrogen-2 (deuterium), helium-4, and lithium-6 are 2.014102 amu, 4.002602 amu, and 6.0151228 amu, respectively. For each isotope, calculate
(c) the nuclear binding energy per nucleon.
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Ch.21 - Nuclear Chemistry
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232
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Table of contents
- Ch.1 - Introduction: Matter, Energy, and Measurement177
- Ch.2 - Atoms, Molecules, and Ions231
- Ch.3 - Chemical Reactions and Reaction Stoichiometry216
- Ch.4 - Reactions in Aqueous Solution189
- Ch.5 - Thermochemistry175
- Ch.6 - Electronic Structure of Atoms168
- Ch.7 - Periodic Properties of the Elements150
- Ch.8 - Basic Concepts of Chemical Bonding177
- Ch.9 - Molecular Geometry and Bonding Theories200
- Ch.10 - Gases179
- Ch.11 - Liquids and Intermolecular Forces113
- Ch.12 - Solids and Modern Materials154
- Ch.13 - Properties of Solutions157
- Ch.14 - Chemical Kinetics199
- Ch.15 - Chemical Equilibrium128
- Ch.16 - Acid-Base Equilibria164
- Ch.17 - Additional Aspects of Aqueous Equilibria163
- Ch.18 - Chemistry of the Environment105
- Ch.19 - Chemical Thermodynamics164
- Ch.20 - Electrochemistry171
- Ch.21 - Nuclear Chemistry122
- Ch.22 - Chemistry of the Nonmetals82
- Ch.23 - Transition Metals and Coordination Chemistry79
- Ch.24 - The Chemistry of Life: Organic and Biological Chemistry16
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232Not the one you use?Change textbook
Chapter 21, Problem 46
The thermite reaction, Fe2O31s2 + 2 Al1s2 ¡2 Fe1s2 + Al2O31s2, H = -851.5 kJ>mol, is one of the most exothermic reactions known. Because the heat released is sufficient to melt the iron product, the reaction is used to weld metal under the ocean. How much heat is released per mole of Al2O3 produced? How does this amount of thermal energy compare with the energy released when 2 mol of protons and 2 mol of neutrons combine to form 1 mol of alpha particles?
Verified step by step guidance1
Identify the given enthalpy change (ΔH) for the reaction, which is -851.5 kJ. This value represents the heat released when the reaction proceeds as written.
Note that the stoichiometry of the reaction shows that 1 mole of Al2O3 is produced per reaction cycle. Therefore, the heat released per mole of Al2O3 produced is directly given by the ΔH of the reaction.
Understand that the comparison with nuclear reactions, such as the combination of protons and neutrons to form alpha particles, involves different scales of energy. Nuclear reactions typically release much greater amounts of energy per mole than chemical reactions.
To compare the energies, you would need the specific ΔH value for the nuclear reaction mentioned. This typically involves looking up or calculating the energy released based on mass defects and conversion into energy using Einstein's equation E=mc^2.
Finally, compare the magnitude of the energy released in the thermite reaction to that of the nuclear reaction to understand the scale and applications of each type of reaction.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Thermodynamics and Enthalpy
Thermodynamics is the study of energy transformations, and enthalpy (ΔH) is a key concept that measures the heat content of a system at constant pressure. In the thermite reaction, the negative ΔH value indicates that the reaction is exothermic, meaning it releases heat. Understanding how to interpret ΔH allows us to calculate the heat released per mole of products formed, such as Al2O3.
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Enthalpy of Formation
Stoichiometry
Stoichiometry involves the calculation of reactants and products in chemical reactions based on balanced equations. In the thermite reaction, the coefficients indicate the molar ratios of reactants and products. By applying stoichiometric principles, we can determine the amount of heat released per mole of Al2O3 produced by relating it to the total heat released in the reaction.
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Nuclear Reactions and Energy Release
Nuclear reactions, such as the fusion of protons and neutrons to form alpha particles, release energy due to the conversion of mass into energy, as described by Einstein's equation E=mc². This energy release is typically much greater than that of chemical reactions. Comparing the energy released in the thermite reaction with that from nuclear fusion highlights the significant differences in energy scales between chemical and nuclear processes.
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02:06Nuclear Binding Energy
Related Practice
Textbook Question
How much energy must be supplied to break a single aluminum-27 nucleus into separated protons and neutrons if an aluminum-27 atom has a mass of 26.9815386 amu? How much energy is required for 100.0 g of aluminum-27? (The mass of an electron is given on the inside back cover.)
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Textbook Question
Potassium-40 decays to argon-40 with a half-life of 1.27 * 109 yr. What is the age of a rock in which the mass ratio of 40Ar to 40K is 4.2?
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