Chemistry - How many atoms of Hydrogen are in 2.05 pg of Humulone? 
Please provide a detailed description of each step in the process.  I
am more interested in how to solve this problem, than in the answer
itself.

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Clarification of Question by gotmike-ga on 16 Apr 2005 17:51 PDT

In response to the first comment below the pg in the question is meant
to be picograms.  Hope this helps.

By the way the anaysis in the comment is right on point.  I am hoping
someone might be able to go through the steps in detail, with the
actual numbers so that I can compare with how I tried to do it and see
where I went wrong.

Thank for your help.

By pg to you mean mg or something?? Not sure what unit of mass a pg is :S

However, given that the formula for Humuolone is C21H30O5 (I believe,
havn't done chem in a while), all you'd need to do is a few simple
converions.

I.e. 2.05 grams of Humulone (or wahtever the mass is in grams) % Molar
mass of Humulone (i'd figure it out for you, but don't have a periodic
table near me!)

^^ the above gives you the moles of Humulone. Multiply that number by
avagadro's constant, and then multiply THAT number by the number of
Hydrogen atoms in the molecule (30, if my original formula is correct)

Okay :D

3 picograms = 3.0 × 10-12 grams (thanks google!)

therefore # of moles = mass / molar mass
                     = 3.0 × 10^-12 grams / 362.47
                     = 8.277 * 10^-15

therefore # of molecules = # of moles * avagadro's constant
                         = (8.277 * 10^-15) * (6.02 × 10^23)
                         = 4982481309

therefore # of atoms = # of molecules * # of hydrogen in each molecule
                     = 4982481309 * 30
                     = 1.495 * 10^11

eh? doe sthat sound right?? I actually kinda lied, I'm a 4th year chem
student at a univeristy. I really hope I'm right, or maybe I should
consider a career change :P

Thanks for that analysis.  It really helped.  I didn't understand the
last part about multiplying by 30.  I would gladly pay you the three
bucks for that answer.  Do you need to submit it as an answer?

Is there any way that I could shoot you questions like that one
occasionally for your analysis?  Sometimes I can't figure out why my
equations don't match the answers from the book. If I post them from
time to time on Google answers do you think you will see them?  Thanks
for your help.

I was just reading my last post and I realized that it looked like I
was saying that I didn't understand the answer that snookersmyhero
posted.  I was trying to say that I didn't realize that I needed to
multiply by thirty, and the answer helped me understand it.

I am very pleased.  snookersmyhero, if you submit your analysis as an
answer I will accept it so you can get paid.

Thanks again for your help.