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Homework Help: Electrostatic force betwen two ions

  1. Jan 14, 2010 #1
    1. The problem statement, all variables and given/known data

    A. Find the electrostatic force between a Na+ ion and a Cl- ion separated by 0.5 nm.
    B. Would the answer change if the sodium ion were replaced by Li+ and the CL ion by Br-?Explain.

    2. Relevant equations
    I believe you have to use Coulomb's Law....?
    F=k* [(/q1//q2/) divided by (r^2^)]

    3. The attempt at a solution
    I have several of these to do and I'm not really sure where to even begin. If someone could show me step by step how to do this, I would be really greatful. Thanks!
  2. jcsd
  3. Jan 14, 2010 #2


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    Science Advisor
    Gold Member

    Just use coulomb's law. Plug in q1 and q2 and r and you're done!

    q1=+1e and q2=-1e where e is the fundamental electric charge (you can just look up the conversion to coulombs). r=.5nm.
  4. Jan 14, 2010 #3
    Thank you!
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