Problem set 4

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Masses and Binding Energy

1: For this exercise the mass excess is used. The needed values are:

  • n: 8071.3171 keV
  • 1H: 7288.97050 keV
  • 4He: 2424.91656 keV
  • 56Fe: -60605.4 keV
  • 142Ce: -84583 keV
  • 238U: 47308.9 keV

more values can be found at

  1. Calculate the mass of the following nucleides: n, 1H, 56Fe, 142Ce and 238U
  2. Which of these nuclieds is the most stable.
  3. Assume that 1.00 kg 2H fuse to give pure 4He. What is the change in mass, what is the amount of energy produced (Mev and kWh)
  4. Assume 1.00 kg233U fission spontaniusly and that the products only are 92Rb and 128Cs and 3 netruons per fission. What is the change in mass and what is the energy produced
  5. Which form of energy is the most importan with fission? Is it radiation or some other form of energy?

2: Calculate the binding energy per nucleon for 24 Mg by using a table or database for atomic mass excess.

3: What is the ratio between the nuclear binding energy and the electron binding energy for 23Na when the ionisation potential of natrium is 5.14 V?

4: Use Einsteins formula and calculate the mass in MeV of the following particles:

  1. A neutron.
  2. A electron.
  3. The atomic mass unit “u”.

5: Calculate the average binding energy, given in MeV of the nucleons in the following nuclei:

  1. 40Ca with mass 29.9627 u.
  2. 56Fe with mass 55.9352 u.
  3. 208Pb with mass 207.9775 u.

6: Assume that a 233U nucleon fission and you get a 131Xe nucleus and a 101Ru nucleus and 3 netruons. What is the energy ?

  • 235U: 40.916 MeV.
  • 131Xe: -88.421 MeV.
  • 101Ru: -87.952 MeV.
  • neutron: 8.071 MeV.

7: Assume that by fission of uranium we get a energy of 200 MeV per nucleus. How far can you drive a car with 1 g of 235U as fuel. When a car uses aproximatly, unless american, 1L of gasoline (density 0.70 g/cm^3) for every 10 km? The heat of burning for catan is 5500kj/mole and a gasoline engine can use 18% of the energy.

8: calculate the ammount of energy between a reaction of hydrogen and oxygen compare the energy with that of creation of He from neutrons and hydrogen (proton+electron).
DeltaG for H_2O is -237 kJ/mol and 0.0303 u is liberated when two protons two neutrons and two electronse fuse to a He-atom.

9: Determine if fusion of deuterium to helium gives more or less energy per gram than fission of uranium.

10: explain why we never find more than one stable nuclide in a isobarchain of odd nummber but in a isobarchain of even number it is possible to find more.

11: explain where we can find nuclides that desintergates with both beta+ and beta-. In addition explain why they have to be nuclei with odd proton and odd neutron.