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Stoichemistry Sucks!! Help!

Discussion in 'Pre-Dental' started by pre-dentalguy, Mar 23, 2007.

  1. pre-dentalguy

    pre-dentalguy Senior Member 7+ Year Member

    532
    2
    Jan 7, 2006
    GA
    Hey guys, I think I got this answer incorrect on my quiz which lost me 5 points. I know this is quite simple to many of you, but I hate stoichemistry with a passtion.

    Do you mind giving me a hand with this one?

    2Al(s) + 6HCl(aq) 2AlCl3(aq) + 3H2(g)
    According to the equation above, how many grams of aluminum are needed to completely react with 1.11 mol of hydrochloric acid?


    A 90 g
    B 29.9 g
    C 10.0 g
    D 13.5 g
    E 1.11 g


    - Marion
     
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  3. Zanderale6

    Zanderale6 7+ Year Member

    213
    0
    Oct 26, 2006
    MA
    Answer: C

    According to your equation, for every mole of Al that reacts, three moles of HCl will react. Since you're told that 1.11 moles of HCl are reacting, simply divide 1.11 by three to come up with the number of moles of Al that will be needed to complete the reaction. Once you have the number of moles of Al required, simply multiply that number by 27 (the molecular weight of Al) to arrive at the total number of grams Al required.

    Hope that helps ... :thumbup:
     
  4. pre-dentalguy

    pre-dentalguy Senior Member 7+ Year Member

    532
    2
    Jan 7, 2006
    GA
    Many thanks bro!! I did the equation completely wrong, but I'm good now. I don't understand how I can breeze through graduate school and get an MBA, but struggle with simple science based courses.

    Is stoichemistry done in Dental school at UPenn? Is stoichemistry in Organic Chem?
     
  5. Fuji

    Fuji 2+ Year Member

    371
    2
    Sep 1, 2006
    You won't be doing stoichiochemistry in o-chem, but you will need to understand the concepts of mass and charge conservation.
     
  6. ladybug123

    ladybug123 2+ Year Member

    24
    0
    Dec 4, 2006
    stoichemistry? stoichiochemistry? please don't take offense but you guys just made me laugh. :idea: It's been awhile since i've had a formal chem class, but isn't it supposed to be stoichiometry?
     
  7. Zanderale6

    Zanderale6 7+ Year Member

    213
    0
    Oct 26, 2006
    MA
    I don't recall stoichiometry being a prominent feature in any of my organic chemistry classes. ... As far as Penn goes, I have no idea at all. I won't be starting there until August. Chances are good that it won't hurt you to master this skill.
     
  8. Yeyyy

    Yeyyy Senior Member 2+ Year Member

    206
    0
    May 1, 2006

    yah... i gotta agree with the stoichiometry thing
     

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