# Stoichemistry Sucks!! Help!

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

1. ### pre-dentalguy Senior Member 7+ Year Member

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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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2. ### Zanderale6 7+ Year Member

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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 ...

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3. OP

### pre-dentalguy Senior Member 7+ Year Member

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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?

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4. ### Fuji 2+ Year Member

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You won't be doing stoichiochemistry in o-chem, but you will need to understand the concepts of mass and charge conservation.

5. ### ladybug123 2+ Year Member

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

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6. ### Zanderale6 7+ Year Member

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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.

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7. ### Yeyyy Senior Member 2+ Year Member

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yah... i gotta agree with the stoichiometry thing

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