Final answer:
The question concerns calculating the weight of a mixture of uranium isotopes, implied by the term 'Udon'. To find the weight of the isotopes, one must multiply the mass of each isotope by its abundance and sum the products.
Step-by-step explanation:
The question appears to be discussing the weight or count of a substance, likely referring to isotopes of uranium based on the context given. When we discuss atomic mass units (a.m.u.) in relation to isotopes, we are typically considering how atomic mass varies between different atoms of the same element. Uranium has several isotopes, among which uranium-235 and uranium-238 are the most common. The 235 signifies the atomic mass number, which is the sum of protons and neutrons in the nucleus.
The information provided suggests that we have a mixture of isotopes and are trying to find the combined weight of uranium isotopes in a sample. If the rod mentioned in the context has 20 times more uranium than just the 235 U part, it implies some calculation involving both isotopes' abundances or weights. The specific numbers provided (84: 0.185 out of 235 a.m.u.) appear to be part of a larger calculation, but on their own are insufficient to provide a full answer. To calculate the weight of Udon (which in this context is being used to denote a uranium isotope mixture, even though 'Udon' is typically a type of noodle), additional information about the complete composition of the sample, including the presence and proportions of both isotopes, would be required.
In a real-world scenario, the weight of a sample of uranium isotopes would be calculated by multiplying the mass of each isotope by its relative abundance and then summing up these products to find the total weight. This is due to the fact that different isotopes have different masses, and thus, their individual abundance in a sample will affect the overall mass.