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Differences Between Nuclear and Chemical Reactions

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					Differences Between Nuclear
  and Chemical Reactions
Introduction


On March 1, 1896, Henry Becquerel made one of the most important discoveries of
our time by accident. Becquerel put a couple of photographic plates that were
completely sealed in paper in a drawer next to a rock, identified as uranium ore, and
left them there, After a few days, he developed the plates and discovered strange
bright spots . Becquerel discovered that uranium gives off invisible rays. Although
we cannot see these rays, they will cause photographic materials to react, just as
visible light causes film to be exposed. The invisible rays from the uranium ore were
able to pass directly through paper and cause the bright spots that formed on
Becquerel's photographic plate. Materials that give off such invisible rays are said to
be radioactive
What is the use of radioactivity?



Today, radioactive materials help us to look inside
ourselves.
The interaction between nuclear
radiation and matter is called a “nuclear
reaction”, two nuclei come close together,
exert forces on one another, and one or
both undergo a change.
Chemical reactions involve electron sharing or
exchange of electrons. They do not occur in the
nucleus.
Nuclear reactions involve a change in the nucleus.
There are forces in the nucleus. One of them is
„The Strong Force‟ holding protons and neutrons
together. The other one is the electrostatic force of
protons repelling other protons. Sometimes,
electrostatic forces can cause instability and can
cause the nucleus to decay. When it reaches a
stable condition, it stops to decay.
                 In Nuclear Reactions

• Protons and neutrons react inside the nucleus.

  Ex:   13N   → 13C + 0β+
         7       6    1


  In the example, nitrogen turns into carbon by changing one
  of it‟s protons to neutron, by decreasing it‟s proton number
  and inreasing it‟s neutron number, but not changing it‟s
  total nucleon number.
                 In chemical reactions

• Electrons react outside the nucleus.

  Ex:              H2 + O 2 → ½ H2O

  This example shows a chemical reaction.
  There is no change in proton or neutron number.
  Proton number = Atomic Number, so there is also no
  change in atomic number.
       In nuclear reactions

• Elements change and turn into other
  elements.
        In chemical reactions

• There is no change in the kind of atom.
  Elements do not turn into other elements.
  The number of elements in the reactants are
  equal to the number of elements in the
  products.
  Atomic number and mass number are kept
  constant.
        In nuclear reactions


• Isotopes react differently.
      In chemical reactions


• Isotopes react the same.
        In nuclear reactions



• Chemical combinations are not
  important in nuclear reactions.
      In Chemical Reactions


• Chemical reactions depend on the
  chemical combinations.
       In nuclear reactions


• Mass of the reactants are not equal
  to the mass of the products.
         In chemical reactions


• Mass of the reactants are equal to the mass of
  the products at the end of the chemical
  reactions.
          In nuclear reactions
• The energy, obtained in nuclear reactions,
  is more than the energy obtained in
  chemical reactions.

 Energy change in
 nuclear reaction → 108 kj
      In chemical reactions
Energy, obtained in chemical reactions, is less
than the energy obtained in nuclear reactions.

Energy change in
chemical reactions → between 10 – 103 kj
   As a summary...



Six Differences between nuclear reactions and chemical reactions.

Nuclear Reactions                       Chemical Reactions
1. Protons and neutrons react
   inside nucleus.
                                   2. Electrons react outside the nucleus.
inside the nucleus
2. Elements transmute into other   2. The same number of each kind of
      elements.                      atom appear in the reactants and products.
3. Isotopes react differently.     3. Isotopes react the same.
4. Independent of chemical
combination.
                                   4. Depend on chemical combination.

5. Energy changes equal 10^8 kJ.
             10 - 10^3 kJ/mol.
                                      5. Energy changes equal

6. Mass changes are detectable.       6. Mass reactants = mass products.
Questions:

1-Mass of the reactants is equal to the mass of the products
in.........reactions.
Answer: Chemical




2- Energy obtained in chemical reactions is.......kilojoules.
Answer:10- 103 kilojoules




3- Isotopes react differently in...........reactions.
Answer: Nuclear



.
4- Electrons react outside the nucleus in................reactions
but protons and neutrons react inside the nucleus in
................reactions.
Answer: chemical , nuclear




5- Elements..........into other elements in nuclear reactions.
Answer: turn




6- Chemical combination is important in ........................
Answer: chemical reactions.
     Resources:


http://physics.bu.edu/py106/notes/RadioactiveDecay.html

http://academic.brooklyn.cuny.edu/physics/sobel/Nucphys/react.html

http://t2.lanl.gov/tour/sch002.html

http://www.uh.edu/hti/cu/1999/v02/04.htm#Objective%201:%20Radi
oactive%20Isotopes
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