The fission of U-235 produces 3.2 * 10-11 J/atom. How much energy does it produce per mole of U-235? Per kilogram of U-235?

Nuclear chemistry is a fascinating field of chemistry that deals with the reactions and processes involving the atomic nucleus, especially the changes in nuclear composition. One significant process, which is the focus of our exercise, is nuclear fission. During fission, an atomic nucleus splits into smaller parts, often producing free neutrons and photons (in the form of gamma rays), and releasing a very large amount of energy.

In nuclear reactors, fission is initiated by the absorption of a neutron by a nucleus, such as uranium-235 (U-235). The resulting heavy nucleus becomes unstable and splits into lighter elements, releasing energy predominantly as heat, which can then be harnessed to produce electricity. Understanding the specific calculations of energy release in fission is crucial for energy management and safety assessments in nuclear power generation.

A cornerstone of chemistry is Avogadro's number, denoted as \(6.022 \times 10^{23}\). It represents the number of constituent particles, usually atoms or molecules, that are contained in one mole of a substance. This constant allows chemists to count particles by weighing, as it bridges the gap between the atomic scale and the macroscopic scale.

When we calculate the energy released by nuclear fission per mole, we multiply the energy released per atom by Avogadro's number. It's an essential step to transition from the micro perspective (single atoms) to a macro view (large quantities of atoms), which is much more practical for applications and measurements in real-world scenarios.

The molar mass of a substance is the mass of one mole of that substance. It essentially indicates how much one mole of atoms weighs, and its units are grams per mole (g/mol). For instance, the molar mass of uranium-235 is approximately 235 g/mol. This value is critical when it comes to converting energy per mole into energy per kilogram.

By knowing the molar mass, we can determine how many moles are in a given kilogram of the substance, which further allows us to calculate the energy produced from a specific amount of material. In practical terms, it helps us scale the energy output calculations from a molecular level to quantities that are handled in industrial processes.

Energy conversion is the process of changing one form of energy into another. In the context of nuclear fission, the conversion we concern ourselves with is the transformation of nuclear energy, inherent in the bonds holding the nucleus together, into thermal energy (heat) that can be utilized to generate electricity in nuclear power plants.

The exercise you are working on involves an energy conversion calculation, where the energy released per atom during fission is converted to energy per mole and then to energy per kilogram. This chain of conversions reflects how scientists and engineers translate the raw power of the atomic realm into usable energy on a scale meaningful for practical applications, such as powering cities or spacecraft.