Notices

View Poll Results: Can Carbon (atoms) be used to fight fire?

Voters
10. You may not vote on this poll
  • Yes

    7 70.00%
  • No

    2 20.00%
  • Not Sure

    1 10.00%
Results 1 to 12 of 12

Thread: How energy is given and taken form this process?

  1. #1 How energy is given and taken form this process? 
    Forum Freshman theorein's Avatar
    Join Date
    Feb 2006
    Location
    Malaysia
    Posts
    13
    c + o2 --> CO2

    How much energy is needed to start this process and how much energy it gives out when once the process has begun and ended?

    I need the amount for 1 ATOM of Carbon + 1 Molecule of Oxygen NOT in grams.


    Reply With Quote  
     

  2.  
     

  3. #2  
    Forum Senior silkworm's Avatar
    Join Date
    Nov 2005
    Location
    Kansas
    Posts
    337
    I'm here too.

    Carbon is fuel for fire. It needs oxygen too (for combustion to occur). Maybe sometime this weekend I can calculate it for you, I just don't have time right now.

    Maybe I can find the time to even explain the chemistry to you. It can all be explained with an understanding of spontaniety in reactions and Gibbs Free Energy.


    Reply With Quote  
     

  4. #3  
    Forum Professor
    Join Date
    May 2005
    Posts
    1,893
    The creation of CO2 from O2 and solid carbon releases 393 kJ/mol.

    393000J / (6.022x10^23) = 6.5x10^-19 joules released when one CO2 molecule forms.
    Reply With Quote  
     

  5. #4 How was this calculated? 
    Forum Freshman theorein's Avatar
    Join Date
    Feb 2006
    Location
    Malaysia
    Posts
    13
    Quote Originally Posted by Scifor Refugee
    The creation of CO2 from O2 and solid carbon releases 393 kJ/mol.

    393000J / (6.022x10^23) = 6.5x10^-19 joules released when one CO2 molecule forms.
    Did you first used a large amount of carbon or charcoal and then calculated the the value for a single atom?

    If that is the case, I am NOT convinced. What I need is how much energy will the reaction between one ATOM carbon and one Molecule CO2 will need t start and how much enery will be release once the reaction is over.

    No chain reaction like when you burn a charcoal.
    Reply With Quote  
     

  6. #5  
    Forum Senior silkworm's Avatar
    Join Date
    Nov 2005
    Location
    Kansas
    Posts
    337
    Well, if that calculation is is based on one mole you can simply divide it by 6.02 x 10^23 (Avagadro's Number).... ....

    Actually Scifor Refugee has already done that. He has provided your number.
    Reply With Quote  
     

  7. #6 But can you proof that this energy came from this reaction? 
    Forum Freshman theorein's Avatar
    Join Date
    Feb 2006
    Location
    Malaysia
    Posts
    13
    Quote Originally Posted by silkworm
    Well, if that calculation is is based on one mole you can simply divide it by 6.02 x 10^23 (Avagadro's Number).... ....

    Actually Scifor Refugee has already done that. He has provided your number.
    Is there concrite proof that C + O2 will produce this amount of energy or was it an assumption?

    --------------------------
    Sorry for mistake in Equation. Correction made.
    Reply With Quote  
     

  8. #7  
    Forum Senior silkworm's Avatar
    Join Date
    Nov 2005
    Location
    Kansas
    Posts
    337
    Well, C + CO2 will do nothing (because there's no advantage in energy for the reaction to take place). C + O2 when given a spark will react spontaneously to give that per atom of carbon and molecule of oxygen. It is very well established, and this reasoning does not work just for this reaction but all reactions. I'm not going to hold your hand and walk you through it because it's actually pretty involved. I gave you a suggestion to study Gibbs Free Energy, which is a solid starting point.
    Reply With Quote  
     

  9. #8 Re: How was this calculated? 
    Forum Professor
    Join Date
    May 2005
    Posts
    1,893
    Quote Originally Posted by theorein
    Did you first used a large amount of carbon or charcoal and then calculated the the value for a single atom?

    If that is the case, I am NOT convinced. What I need is how much energy will the reaction between one ATOM carbon and one Molecule CO2 will need t start and how much enery will be release once the reaction is over.

    No chain reaction like when you burn a charcoal.
    Do you want to react a carbon atom with O2 or CO2? I assume you meant O2, like you said in your original post.

    If you want to react a cloud of neutral single-carbon-atom gas with O2, it would release 114 kj/mole. That's the energy difference between the O2 double-bond and the two CO double bonds that form. There is more energy in the O2 bond than in the CO2 bonds, so you get a net energy release.
    Reply With Quote  
     

  10. #9 How to find who voted and how they voted? 
    Forum Freshman theorein's Avatar
    Join Date
    Feb 2006
    Location
    Malaysia
    Posts
    13
    May I know who is the other person who voted YES and why?
    Reply With Quote  
     

  11. #10  
    Forum Professor
    Join Date
    May 2005
    Posts
    1,893
    There is less energy in the two carbon-oxygen bonds of CO2 than there is in the oxygen-oxygen bond of O2. So if you convert O2 and C into CO2, the energy has to be released.
    Reply With Quote  
     

  12. #11  
    VM
    VM is offline
    Forum Freshman
    Join Date
    Feb 2006
    Posts
    8
    Quote Originally Posted by Scifor Refugee
    There is less energy in the two carbon-oxygen bonds of CO2 than there is in the oxygen-oxygen bond of O2. So if you convert O2 and C into CO2, the energy has to be released.
    But this is not a reason why it could be used as a fire extinguisher, correct? If it releases energy, then it would ADD to the fire.

    I said, yes, it could be used to put out a fire, but the reason why is that if you poured a large amount of carbon onto a fire, it would smother it. I guess it is all a question of how you are trying to use the carbon to fight the fire.
    Reply With Quote  
     

  13. #12  
    Forum Freshman
    Join Date
    Apr 2006
    Posts
    16
    my guess is that the combustion of carbon produces CO2, starving the fire of oxygen?
    Reply With Quote  
     

Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •