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Homework Help: How many of C8H8's electrons has it gained/lost?

  1. Jan 26, 2009 #1
    1. The problem statement, all variables and given/known data
    Assume the formula for styrofoam (a polymer containing carbon and hydrogen) is C8H8. In a .25g styrofoam peanut, how many electrons and protons are present if it carries no excess charges? How many Coulumb's of + and - charge does this stand for? How many of the peanut's electrons has been gained/lost if the peanut has an excess charge of +0.10 C?

    2. Relevant equations

    3. The attempt at a solution
    Well, if this is a typical chemistry problem, in the beginning... I would convert grams to molecules using Avogadro's number.
    Not sure how to find the number of protons and electrons after that though. Doesn't it have to do with the atomic number?
    After that, I'm not exactly sure how to find Coulumb's of the + and - charges.
  2. jcsd
  3. Jan 26, 2009 #2
    Good start.

    The number of protons in a single atom of a given element is equal to the atomic number. If the sample contains no excess charges, you should be able to find the number of electrons based on the number of protons.

    An elementary charge (the charge of one proton (+) or electron (-)) is equal to 1.602 × 10–19 Coulombs.
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