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Molecular Weight for nucleotides

  1. Apr 12, 2005 #1
    When it says; "Molecular Weight: daltons (g/M)" What does daltons mean and what does (g/M) stand for? Does g/M stand for g/mol or what?

    How can they calculate Molecular Weight for nucleotides?


    Thanks for any inputs.
     
  2. jcsd
  3. Apr 12, 2005 #2

    Monique

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    A dalton is an atomic mass. For instance C12 has a mass of 12.0000 Da. The mw is the mass of 1 mole of a particular molecule. By definition 1 mole of carbon atoms weighs 12 grams.
     
  4. Apr 12, 2005 #3
    Thanks.

    But what does M stand for in g/M?
     
  5. Apr 12, 2005 #4

    Moonbear

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    You had it right...mole.
     
  6. Apr 13, 2005 #5
    (why only four zeros?)

    (1) C12 has a mass of 12 Da (by definition; exactly 12, there is no uncertainty)
    (2) a mol of C12 atoms weighs 12 grams (by definition)

    From (1) and (2) it follows that a dalton is the number of grams that go into a mol (gram/mol)
    __________________________________________________
    (1) C12 = 12 Da <--> mol C12 = mol 12 Da
    (2) mol C12 = 12 gram
    (substitute 2 into 1) 12 gram = mol 12 Da <--> gram/mol = Da
     
  7. Apr 13, 2005 #6
    doesn't g/M mean g/mol/L?
     
  8. Apr 13, 2005 #7

    cronxeh

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    its not exactly 12, and its not exactly 16 for oxygen either

    but they decided to make it 12 anywho. so just use 12 as a whole number

    6 protons = 6 x 1.007277 6.043662
    6 neutrons = 6 x 1.008665 6.051990
    6 electrons = 6 x 0.000548 0.003288
    Total 12.098940
     
    Last edited: Apr 13, 2005
  9. Apr 13, 2005 #8

    Monique

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    Carbon was easy to purify, that is why they used it as a reference and why it is the whole number 12.
     
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