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Homework Help: Chemical Equations

  1. Jan 11, 2012 #1
    Calculate the amounts requested if 3.3 mol of Fe[itex]_{2}[/itex]O[itex]_{3}[/itex]
    Fe[itex]_{2}[/itex]O[itex]_{3}[/itex]+2Al[itex]\rightarrow[/itex]2Fe+Al[itex]_{2}[/itex]O[itex]_{3}[/itex]

    a)Find the moles of aluminum needed
    b)Find the moles of iron formed
    c)Find the moles of aluminum oxide formed


    Not sure how to go about solving any of these the book is terrible and doesnt explain anything and I cant seem to find good notes online.

    Im thinking that
    a)6.6 moles because there is a 2 infront
    b)6.6 again same reason
    c)3.3 to even out the moles used
     
  2. jcsd
  3. Jan 12, 2012 #2
    Good job, your answers are exactly correct.
    But your reasoning might be a little off on part 'c'. You end up with 3.3 moles of aluminum oxide because it has the same number in front as the Fe2_O3 you started with.

    Consider this example:
    [tex]A + B \rightarrow AB[/tex]
    There are two moles of substance on the left, but only one on the right---and that is totally fine. The number of moles of particular substances doesn't need to match on each side---as long as the number of atoms matches (there is 1 mol of A, and 1 mol of B on each side).
     
  4. Jan 12, 2012 #3

    Borek

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    Staff: Mentor

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