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Homework Help: Nuclear charge from a potential electrostatic energy

  1. Jul 4, 2014 #1


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    Question: "Given an electrostatic potential energy of -6.16x10^-18 J and a distance of 1.12x10^-10m, what is the nuclear charge if there is a single electron interacting with the nucleus?"

    Okay, Equation:
    PE = [K*Q1*Q2]/d

    Where K is a constant of 8.99*10^9 J*m/c
    d is giving at 1.12*10^-10m
    PE is giving at -6.16*10^-18 J
    Q1 is giving as the charge of an electron at 1.602 * 10^-19 C
    Q2 is what we solve for, which, plugging in the equation is -4.79*10^-19

    This equation is easy enough to plug in. HOWEVER, am I answering the equation? Is Q2 = to the nuclear charge? I guess that is where I am confused.

    And for Q2 I received a negative charge, I would imagine this is correct since PE is initially negative and the charge of an electron was positive? Or do I have it backwards?

    Thank you
    Last edited: Jul 5, 2014
  2. jcsd
  3. Jul 5, 2014 #2


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    I just realized I may have posted this with the worst possible title of a thread. I apologize.

    Can anyone confirm that the MOLAR MASS of Mo(CO)6 is 264.0 ?
  4. Jul 5, 2014 #3


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    Yep, looks OK.
  5. Jul 5, 2014 #4


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    Interesting. I got that answer marked wrong on the online application. It must be due to the amount of figures, however the question explicitly states to go to one decimal point on all of these questions. I will e-mail my professor before going through my second attempt.

    Anyone have any idea on the first one? I got it marked incorrectly and I am not sure if its because of the sign, significant figures or error in calculation.
  6. Jul 5, 2014 #5


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    Sorry for posting all of my junk here. However, I am having the most difficulty with this homework. I want to understand, but I feel like I am missing an integral piece. Anyway, I will keep treading on. Here is my next question.

    "For the reaction between Iron and sulfuric acid, which element is reduced?" And which is oxidized?
    a) Iron
    b) Hydrogen
    c) Sulfur

    Okay. Well, the equation should be

    2Fe (s) + 3H2SO4 (aq) ---> Fe2(SO4)3 (aq) + 3H2 (g)

    Oxidization refers to loss of electrons in the reaction. Reduction is the gain of electrons.

    Well naturally, Iron will look to loss electrons. So that would make it the obvious choice to be oxidized.
    However, who gains electrons? My initial guess is "Sulfate." However, that is not an option. I attempted with oxygen previously and it was incorrect. So it must be Sulfur?
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