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Homework Help: Chemistry - test- help

  1. Oct 29, 2005 #1
    a. the first ionization energy of aluminum is 578 kJ/mol. How much energy is required to ionize one atom of Al?
    I put E= 578 kJ/mol . is this how to start?

    b. Write out balanced chemical equation that represents the first ionization of aluminum (you must include the physical states)

    c. Calculate the wavelength of a photon that has just enough energy to ionize a single atom of aluminum.

    d. how many moles of photons with the wavelength you calculated in part c are required to ionize 1.15 moles of aluminum?

    Can you help me set these up. I am studying for a test and we have not been over all of these yet? Thanks.
  2. jcsd
  3. Oct 29, 2005 #2


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    Science Advisor

    the energy given is in terms of moles. You are trying to find the energy for a single atom. So how many atoms in a mole....

    Remember, Aluminum like to ionize to +3.

    Using the equation E = H * C / Lambda,
    where E is the energy of a wave, H is planks constant, C is the speed of light in a vacuum, and Lamba is the wavelength of the wave, you can solve for the wavelength since you know Energy and H and C are constants.
    H = 6.63 E-34 Js/photon
    C =3.0 E8 m/s

    I think 1 photon will ionize 1 atom assuming the photon is of the correct energy.
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