I'm converting 15.0kmol of C6H6 to mol(g-atom)C.?

I converted 15.0kmol to mol=15, 000 mol of C6H6. And for every mol of benzene, there is 6 mol of C. Now I got 90, 000 mol of C.

But I think it is missing something, the question is asking "mol(g-atom)C", clearly my answer does not have (g-atom).

What should I do here, should I multiply it by Avogadro's number? can you please explain.

Update:

Thanks for the clarification, and also for the reminder about the significant figures.

2 Answers

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  • Dr W
    Lv 7
    1 month ago

    First.. you're getting into some crazy abstract, obsolete and inconsistent units from the dark ages. Just be aware that many people in chemistry fields aren't exposed to this stuff. Your instructor is ancient and crusty I take it?

    anyway.. let's look at some examples

    *********

    example helium

    .. atomic mass = 4 amu / 1 atom

    .. molar mass = 4 grams / 1 mole of atoms.. (4g / 6.022x10^23 atoms)

    if I have 12g of helium

    .. I have 12g * (1mol / 4g) = 3 moles of He atoms = 18.066x10^23 He atoms

    .. I have 12g * (1 gram-atom / 4g) = 3 gram-atoms.

    "gram-atom" is an obsolete term for "mole of atoms" it literally means the amount necessary to have the same mass as the atomic mass as shown on a periodic table. (STUPID wordy backwards ancient hillbilly chemist way of thinking about "moles" in MHO)

    example copper

    .. molar mass = 63.55g / mole of atoms

    .. 127.1g Cu = 2 mol Cu atoms = 2 gram-atoms

    example methane

    .. molar mass = 16.0g / mole of molecules of CH4

    .. 48.0g CH4 = 3 mol of CH4 molecules = 3 gram-molecules

    get it? as insane as it sounds... 

    .. gram-atoms is a synonym for "mole of atoms"

    .. gram-molecules is a synonym for "mole of molecules"

    if it helps.. think of it like this

    .. gram-atom is short for gram-moles of atoms

    .. gram-molecule is short for gram-moles of molecules

    but even that is stupid. 

    BOTH are obsolete today and only used by the old school professors that don't know what else to teach chemistry students. LAME.

    ***********

    This problem

    .. 15.0 kmol C6H6 molecules.. 1000 mol... ... . 6 mol of C atoms

     ----- ----- ----- ----- ---- ----- ---- x ---- --- --- x ---- ---- ---- ---- ---- ----- ---

    .. ... ... .... ... .. 1.. .. .... ... ... .. ... 1 kmol.. ...1 mol of C6H6 molecules

    .. = 9.00x10^4 mol C atoms = 9.00x10^4 gram-atoms of C

    ********

    looks like David and I agree on this one. 

  • david
    Lv 7
    1 month ago

    your answer of 90,000 is almost correct

      the g-atom .. is just BS to confuse you (which it did)

    for teachers or profs that want to be really picky, you need to use sig figs in your answer

      ...  the beginning value of 15.0 has 3 sig figs ... as written,  90,000 has only one sig fig...  write in in exponental notation t show 3 sig figs.

       ...  9.00 x 10^4 mole C

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