Problem set 4
Masses and Binding Energy
Return to Problem Solving Sets
1: For this exercise the mass excess is used. The needed values are:
- n: 8.0713171 MeV
- 1H: 7.28897050 MeV
- 4He: 2.42491656 MeV
- 56Fe: -60.6054 MeV
- 142Ce: -84.583 MeV
- 238U: 47.3089 MeV
more values can be found at http://ie.lbl.gov/toi2003/MassSearch.asp
- Calculate the mass of the following nucleides: n, 1H, 56Fe, 142Ce and 238U
- Which of these nuclieds is the most stable.
- 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)
- Assume 1.00 kg 233U fission spontaneously 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
- 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 24Mg 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 to calculate the mass in kg of the following particles (n = 939,6 MeV, e = 0.511 MeV, u = 931.5):
- A neutron.
- An electron.
- The atomic mass unit “u”.
5: Calculate the average binding energy, given in MeV of the nucleons in the following nuclei:
- 40Ca with mass 29.9627 u.
- 56Fe with mass 55.9352 u.
- 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 200 MeV is released per nucleus. How far can you drive a car with 1 g of 235U as fuel. When a car uses aproximatly 1L of gasoline (density 0.70 g/cm3) for every 10 km? The heat of burning for octane is 5500kj/mole and a gasoline engine can utilize 18% of the energy.
8: Calculate the ammount of energy released between a reaction of hydrogen and oxygen compared to the energy released with the creation of He from neutrons and hydrogen (proton+electron).
ΔG for H2O 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 disintergates with both β+ and β-. In addition explain why they have to be nuclei with odd proton and odd neutron.