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Chemistry Diee !

  1. Dec 1, 2003 #1
    Chemistry!!! Diee!!!!!!

    A few stoicheometry problem,.. I really feel like a noob in chem:(

    A chemist has 5 mol of Cl that combines w/ Al, how many moles of solid Al Chloride is produced?

    First, I set up balance eq.

    5 mol Cl2 + Al ---> AlCl2

    Then by ratio, 5:1, so i got 1 mole of AlCl2 is produced. Pretty sure I made a mistake. Someone help pls. (BTW, how do you determine which charge to use for Al?)
  2. jcsd
  3. Dec 1, 2003 #2
    The equation for the reaction between Cl2 and Al is as follows,

    3Cl2 + 2Al ---> 2AlCl3 (Ionic, Al has a 3+ charge, and Cl has a 1- charge)

    So 3 moles of Cl2 will react to produce 2 moles of AlCl3. Therefore if 5 mol of Cl2 is used to begin with, 3.33333 (10/3) mol of AlCl3 will be produced.

    I may have made a stupid mistake somewhere. If so don't blame me, I have a hangover :smile:

    Edit: How did you make the subscript numbers?
    Last edited: Dec 1, 2003
  4. Dec 1, 2003 #3
    When does Al have 4 charge?

    subscripts are [ sub ] [ /sub ]

    with no spaces.
  5. Dec 1, 2003 #4
    Al has a 3+ charge because in order to get into the nearest noble gas configuration (1s2, 2s2, 2p6), it needs to lose 3 electrons. Theoretically it could indeed have a 4+ charge, but it would not be energetically favourable, therefore it is not likely to occur under normal conditions.
  6. Dec 6, 2003 #5

    Another God

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    You can also now Use Latex. Click on the image to see the code in a pop-up window.

    3Cl2 + 2Al ---> 2AlCl3 (Ionic, Al has a 3+ charge, and Cl has a 1- charge)
    [tex]3Cl_2+2Al \longrightarrow 2AlCl_3[/tex]

    Using the sub /sub flags in normal text can achieve much the same, but this looks cooler :wink:
  7. Dec 6, 2003 #6


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    You said you have 5 mols of Cl. You actually do mean Cl and not Cl2 right?
    The ratio of Cl to AlCl3 is 6:2 or 3:1. So the ratio of AlCl3 to Cl is 1:3

    1AlCl3/3Cl * 5Cl = 1.66666 mols AlCl3
  8. Dec 6, 2003 #7
    The question didnt really give enough info. I was assuming it meant Cl gas, in which case it is Cl2. It may have meant Cl in the ionic form however, in which case you would be correct. From the info he gave though, it sounds as if it is meant to be in the gas, or Cl2, form. And also, he has Cl2 in his original post (in the equation).

    Another God: Thanks, very nifty tool. Working out the commands now :)
    Last edited: Dec 6, 2003
  9. Dec 6, 2003 #8


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    It will look even better if you use itex instead of tex tags:

    [tex]3Cl_2+2Al \longrightarrow 2AlCl_3[/tex]

    [itex]3Cl_2+2Al \longrightarrow 2AlCl_3[/itex]

    It decreases the font and thus allows it to put inline.
    Last edited: Dec 6, 2003
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