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Mass Defect quiz #1

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  • What is the equivalent binding energy (Eb) corresponding to the mass defect of an atom of 18 8O (oxygen-18)?
    To find the equivalent binding energy (Eb) for the mass defect of an atom of 18 8O, first calculate the predicted mass by summing the masses of its subatomic particles: 8 protons (1.00727 amu each), 10 neutrons (1.00866 amu each), and 8 electrons (0.00055 amu each). Subtract the actual nuclear mass (which can be estimated using the nuclear mass equation if not given) from the predicted mass to get the mass defect (Δm). Then, use Einstein's equation, E = Δm × c², to convert the mass defect to energy. This energy is the binding energy (Eb) that holds the nucleus together.
  • What is the relative mass of a neutron in atomic mass units (amu)?
    The relative mass of a neutron is 1.00866 amu.
  • Why does the majority of an atom's mass reside in the nucleus?
    The nucleus contains protons and neutrons, which have much greater masses than electrons.
  • What does the first law of thermodynamics state in the context of mass defect?
    It states that energy cannot be created or destroyed, only transformed, such as mass being converted to energy during isotope formation.
  • How is the predicted mass of an isotope calculated?
    It is calculated by summing the masses of all its protons, neutrons, and electrons.
  • What happens to the mass lost during the formation of an isotope?
    The lost mass is converted into energy, known as the binding energy of the nucleus.
  • What equation allows you to convert between mass and energy in nuclear chemistry?
    Einstein's equation, E = mc², allows conversion between mass and energy.
  • Why is the predicted mass of an isotope always greater than its nuclear mass?
    Because some mass is lost and converted into energy during the formation of the nucleus.
  • What is the nuclear mass equation if the nuclear mass is not given?
    Nuclear mass equals the mass number minus the number of electrons times 0.00055 amu.
  • What role does energy play in breaking up an isotope into its subatomic particles?
    Energy must be absorbed to break up an isotope into its original subatomic particles.