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Sample of glucose (C6H12O6) contains 0.75 moles of Oxygen

  1. Jan 11, 2005 #1
    A sample of glucose (C6H12O6) contains 0.75 moles of Oxygen. How many moles of hydrogen does this sample contain?

    For this problem I was thinking that you might use some kind of ratio between hydrogen and oxygen, but I didn't quite know what to do with carbon?

    Thanks! :biggrin:
  2. jcsd
  3. Jan 11, 2005 #2


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    Yes, you must use the ratio between the number of atoms of hydrogen to those of oxygen in each molecule of glucose. You have no reason to worry about carbon unless asked about it.

    Each molecule has 12 H atoms and 6 O atoms. If there are 100 molecules of glucose, there will be 1200 H atoms and 600 O atoms. For any number n, if I have n molecules of glucose, I should have 12n H atoms and 6n O atoms. If n is the Avogadro number, I should have 12 moles of H atoms and 6 moles of O atoms. In short, there will always be twice as many moles of H atoms as there are O atoms.
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