Monday, December 7, 2009

Mr. Scully TAKE 1

-The molar mass of a compound can be used as a conversion factor. We said this about twenty times at the end of class today, so it must be important.
WHAT IN THE WORLD IS THE MASS OF 2.50 mol of OXYGEN GAS?!?
Don't fret my friend. It's relatively simple. 1st, realize that Oxygen exists in its gaseous state as TWO oxygen bonded to each other.
SHOCKING, I KNOW.
Buy anywho... it's just simple multiplication from here. Oxygen (or oxy, as her friends call her) has a molar mass of 16.00, roughly. Since oxy and her twin sister are hanging out together, that means we have to take 16.00 and multiply it by TWO. Now multiply that by your number of mols, and you have your answer.

so, basically just 2.50*2*16.00

BUT WAIT! HOW MANY SIGNIFICANT DIGITS DO I GO TO?!?
That's enough fretting out of you, bud. When dealing with this problem, just understand that the 2.50 mols is your estimated amount. How many sig-digs does it have? 3. How many sig-digs does your answer have? 3.

=80.0 grams. Bam, Boom, See you later.

Now as most of you remember, Dr. B flashed something about Ibuprofen across the screen for about 2 seconds at the end of class
Perhaps an exaggeration, but I reserve my creative license.
Thankfully, she pointed out to me that the problem's in the book.
<3>And seeing how you're probably already bored with my ridiculous attempts to make 5 minutes of notes in chemistry entertaining, I'll just spell the problem out for you really simply.

Ibuprofen, C13H18O2 is the active ingredient in many nonprescription pain relievers. Its molar mass is 206.31 g/mol
a. If the tablets in a bottle contain a total of 33 g of ibuprofen, how many moles of ibuprofen are in the bottle?
b. How many molecule of ibuprofen are in the bottle?
c. What is the total mass in grams of carbon in 33g of ibuprofen?
Given: 33 g of C13H18O2, molar mass 206.31 g/mol
Unknown: a. moles C13H18O2
b. Molecules C13H18O2
C. total mass of C

Solution
a. 33g * (1 mol/206.31) = 0.16 mol (don't forget sig-digs)
b. 0.16 mol * (6.022*10^23) = 9.6*10^22
c. 0.16 mol * (13 mol) * 12.01 g = 25 g
Posted by at

17 comments:

  1. Ryan DiazDecember 7, 2009 at 3:47 PM

    This comment has been removed by the author.

    ReplyDelete
  2. Ryan DiazDecember 7, 2009 at 3:48 PM

    Naming Compounds
    -Metal to nonmetal: simple with no roman numerals or prefixes
    -Transition metal to nonmetal: transition metal has roman numeral stating the charge with no prefixes
    -Nonmetal to nonmetal: has prefixes

    ReplyDelete
  3. Alex BlandDecember 7, 2009 at 4:00 PM

    misterguch.brinkster.net/PRA001.doc

    Worksheet on molar mass of compounds. Will open download menu. Press open or save as to get a word document.

    ReplyDelete
  4. matt johnsonDecember 7, 2009 at 5:29 PM

    Good with chemical nomenclature
    http://science.widener.edu/svb/pset/nomen_b.html

    ReplyDelete
  5. Glennjamin AdesojiDecember 7, 2009 at 5:32 PM

    website that helps you memorize molar mass conversion

    http://www.800mainstreet.com/6/0006-004-Mole-Mass-Con.htm

    ReplyDelete
  6. Ben SmithDecember 7, 2009 at 5:40 PM

    Michael Scully I love you because that was an amazing blog.

    http://www.webqc.org/mmcalc.php

    Helps you calculate molar mass

    ReplyDelete
  7. Dr. BautistaDecember 7, 2009 at 5:51 PM

    Well, this posting was way over the top for me but I am glad that Ben liked it. I don't like the huge font either.

    Don't forget to study for another naming quiz. We will keep doing these until all y'all can pass them!

    ReplyDelete
  8. Patrick BloseDecember 7, 2009 at 6:32 PM

    Good info on molar mass

    http://en.wikipedia.org/wiki/Molar_mass

    ReplyDelete
  9. Andrew ParmenterDecember 7, 2009 at 6:53 PM

    extremely entertaining...very well done
    site on naming ions

    http://www.ausetute.com.au/namiform.html

    ReplyDelete
  10. Donnie SheaDecember 7, 2009 at 7:02 PM

    Very interesting blog, Michael. But anywho, here's a good site on a review of molar mass, for all of you who need a reminder.

    http://environmentalchemistry.com/yogi/reference/molar.html

    ReplyDelete
  11. Kyle McCafferyDecember 7, 2009 at 7:57 PM

    Guys, I know Dr. B said something about working on the review pages in class, but we should probably work on them tonight.

    Scully, you really have a knack for this kind of thing. Thanks for filling me in on the info, and making me laugh.

    ReplyDelete
  12. H.HillDecember 7, 2009 at 8:05 PM

    This site has sample problems for molar mass calculations.

    http://chemistry.about.com/od/workedchemistryproblems/a/molecularmass.htm

    ReplyDelete
  13. Justin ScheunerDecember 7, 2009 at 8:15 PM

    Yes Dr. B said to continue working on our review packet in anticipation of the next page(s) being assigned

    ReplyDelete
  14. Jim AlrutzDecember 8, 2009 at 4:50 AM

    Alex posted one of these worksheets, but here's an index with several worksheets in PDF and Word format.

    http://misterguch.brinkster.net/conversionsworksheets.html

    Nice blog, Michael.

    ReplyDelete
  15. DuklewskiDecember 8, 2009 at 5:52 AM

    nice blog scully, here's a website on oxidation numbers
    http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch2/oxnumb.html

    ReplyDelete
  16. Will BrantleyDecember 8, 2009 at 3:33 PM

    here is some info about oxidations #'s
    http://www.fordhamprep.org/gcurran/sho/sho/lessons/lesson52.htm

    ReplyDelete
  17. Jacob PoseyDecember 8, 2009 at 4:43 PM

    molermass equations
    http://antoine.frostburg.edu/chem/senese/101/moles/index.shtml

    ReplyDelete

Subscribe to: Post Comments (Atom)