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Homework Help: Ionization and light

  1. Jul 2, 2006 #1
    [SOLVED] Ionization and light

    I've been working on this problem and I'm not coming up with a reasonable answer.

    If the Bohr model is used, what frequency of light
    would be required for ionization of hydrogen?

    I know that [tex]\Delta E = h \nu[/tex], where E is energy, h is Planck's constant, and [itex]\nu[/itex] is frequency and that [tex]\nu = \frac{c}{\lambda}[/tex] and I know the first ionization energy of hydrogen is 1312 kJ/mol, but I can't seem to arrive at the answer.

    I tried using both 1312kJ and 1.312x10^6J for E but the answer comes out too large. The solution is 3.29 × 10^15 Hz. Any help is appreciated.
     
  2. jcsd
  3. Jul 2, 2006 #2
    First step: Questions like this should be on the homework forum, so you probably might want to post there next time.

    Next step: Divide the ionization energy (in J) per mol by 6.023x10^23 to get the ionization energy per electron. You should get a number like 2.1783x10^-18 J which should look somewhat familiar to you. This is your E.

    Next Next step:

    2.7183X10^-18 J = (6.63x10^-34 J*s)f

    f = 3.29x10^15 Hz
     
  4. Jul 2, 2006 #3
    Yep, this is actually my first homework question and I forgot about that forum, actually. Thanks for your response!
     
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