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Stiochemistry practice problems! help

  1. Mar 2, 2007 #1
    1. The problem statement, all variables and given/known data

    Aluminum oxide is formed from the reaction of metallic aluminum with oxygen gas. How many moles of Aluminum are needed to form 3.4 moles of Aluminum oxide?

    2. Relevant equations

    first equation:Al + O2 --> Al2O3 i balanced it at 4Al + 3O2 --> 2Al2O3

    3. The attempt at a solution

    okay I just really need help understanding this because I have no clue what I am doing and don't understand how to work the problem! please help:confused:
  2. jcsd
  3. Mar 2, 2007 #2


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    Staff Emeritus
    Science Advisor

    Ok, so you've balanced your equation correctly. From this you know that 4 moles of aluminium produce 2 moles of aluminium oxide, and want to calculate the number of moles of Al required to produce 3.4 moles of aluminium oxide (x, say).

    1. What is the ratio of Al to Al2O3?
    2. Can you set up a ratio equation for x?
  4. Mar 2, 2007 #3


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    Staff: Mentor

    Learn balanced reaction equation meaning - then you should understand what you are doing :wink:
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