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Homework Help: Unexplained question

  1. Nov 9, 2006 #1
    Hello, I'm new and I have a question about something on my homework that I just can't find an explaination how to do.

    if sodium has an emmsion line at 589nm, what is the energy (in joules) produced by 0.2698 moles of excited sodium atoms?

    The answer is apparently 5.481*10^4

    If anyone could tell me how to go from those above numbers to that answer I would sure appreicate it, thanks in advance.
  2. jcsd
  3. Nov 9, 2006 #2


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    Staff Emeritus
    Science Advisor
    Gold Member

    Some questions to think about;
    1. What is the energy of a single photon with a wavelength of 589nm?
    2. How many sodium atoms in a mole of sodium?
    3. How many sodium atoms in 0.2698 moles of soduim?
    4. Assuming each of the atoms is excited to the same level, how many 589nm photons are produced?
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