G of CO2 per kWh from burning methane

  • Thread starter Thread starter Archosaur
  • Start date Start date
  • Tags Tags
    Co2 Methane Per
AI Thread Summary
The discussion centers around the calculation of CO2 emissions from burning methane (CH4) for energy production. The original source claims that burning methane produces 360 grams of CO2 per kWh of energy. However, upon performing a calculation based on standard enthalpies of formation, a participant arrives at a significantly lower figure of approximately 178 grams of CO2 per kWh. This discrepancy is noted to be close to a factor of two, leading to confusion. The participant later realizes the distinction between measuring heat energy versus electrical energy, which clarifies the misunderstanding regarding the original claim. The conversation highlights the importance of precise definitions in energy calculations and the potential for misinterpretation in scientific discussions.
Archosaur
Messages
333
Reaction score
4
http://europe.theoildrum.com/node/6638" has a chart that claims that the burning of methane yields 360 g of CO2 per kWh of energy released. I decided to check that, but I'm not getting the same answer they suggest. Here's what I did:

CH4 + 2O2 = 2H2O + CO2
-74.87 + 0= 2*-285.83 + -393.509
= -571.66 + -393.509 +74.87= -890.229 kJ/mol

(all standard enthalpies of formation came from wikipedia)

CO2 is 44.011 g/mol
890.229 kJ is 0.24728583333 kWh (significant figures be damned)

44.011/0.24728583333 ≈ 178 g/kWh, as opposed to their 360 g/kWh


I can't help but notice that my answer is suspiciously close to a factor of 2 off... but my eq. is balanced...
Can someone tell me what I've done wrong?

Thanks
 
Last edited by a moderator:
Chemistry news on Phys.org
You say per kWhr of heat, but their graph says per kWhr of electricity.
 
*slaps forehead

I figured I'd be kicking myself.
Thanks, cesiumfrog.
 

Thread 'Solubility of MgSO47H2O in water'

It seems like a simple enough question: what is the solubility of epsom salt in water at 20°C? A graph or table showing how it varies with temperature would be a bonus. But upon searching the internet I have been unable to determine this with confidence. Wikipedia gives the value of 113g/100ml. But other sources disagree and I can't find a definitive source for the information. I even asked chatgpt but it couldn't be sure either. I thought, naively, that this would be easy to look up without...
View full post »

Thread 'Why does having 8 valence electrons make an element inert?'

I was introduced to the Octet Rule recently and make me wonder, why does 8 valence electrons or a full p orbital always make an element inert? What is so special with a full p orbital? Like take Calcium for an example, its outer orbital is filled but its only the s orbital thats filled so its still reactive not so much as the Alkaline metals but still pretty reactive. Can someone explain it to me? Thanks!!
View full post »

Similar threads

Produce Methane Via CO2 + H2O ?
Replies
3
Views
4K
How Can I Store Methane Produced from CO2 and Water Without Combustion?
Replies
23
Views
3K
Energy changes and rates of reaction
Replies
7
Views
2K
Stuck on Reaction Enthelpy Question
Replies
7
Views
2K
Enthalpies of Formation from Methane & Oxygen
Replies
1
Views
10K
How to Determine Standard Enthalpy Change Using Hess's Law?
Replies
5
Views
13K
What Is the Change in Enthalpy for Diamond to CO2 at High Temperatures?
Replies
1
Views
2K
Hess's Law Problem: Finding Enthalpy of Vaporization for H2O
Replies
6
Views
5K
Help with enthelpy change and Hess's Law
Replies
1
Views
4K
Solving Hess' Law for C2H6 Combustion: kJ/mol
Replies
3
Views
7K

Hot Threads

Recent Insights

Back
Top