Moderate

The total number of neutrons in 5g of H2O are:1 NA = 6.023 x 10^23

Correct answer: C. 1.34 x 10^24

  • A. 25 NA
  • B. 1.1 NA
  • C. 1.34 x 10^24
  • D. 0.5 NA

Explanation

To find the total number of neutrons in 5g of H2O, we start by calculating the number of moles of water:1. The molar mass of H2O is approximately 18 g/mol (2 for H and 16 for O).2. The number of moles in 5g of H2O is calculated as follows: Number of moles = mass (g) / molar mass (g/mol) = 5g / 18 g/mol ≈ 0.278 moles.3. Each molecule of H2O contains 2 hydrogen atoms (each with 0 neutrons) and 1 oxygen atom (with 8 neutrons), totaling 8 neutrons per molecule.4. The total number of molecules in 0.278 moles is: 0.278 moles x 6.023 x 1023 molecules/mole ≈ 1.67 x 1023 molecules.5. Therefore, the total number of neutrons in 5g of H2O is: 1.67 x 1023 molecules x 8 neutrons/molecule = 1.34 x 1024 neutrons, which corresponds to Option C. The other options are incorrect due to miscalculations or misunderstandings of stoichiometric principles.

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Mole calculations connect mass, number of particles and Avogadro's number, while balanced equations provide the mole ratios used in stoichiometry. Questions cover limiting and excess reactants, theoretical yield and percentage yield, including identifying which reactant is consumed first and comparing the actual product with the maximum possible product.

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