- #1
Stephanus
- 1,316
- 104
Dear PF Forum,
I'm interested in composting.
I want to understand the benefit of composting.
Besides
I wonder how, without oxygen addition/introduction, in a sealed composter bin, can methane be synthesized?
Wiki (https://en.wikipedia.org/wiki/Fermentation) says that
CH3COO− + H+ → CH4 + CO2
Okay...
So perhaps without introducing energy from outside of the system. Methane can be synthesized.
But now I'm wondering about a new thing.
https://en.wikipedia.org/wiki/Heat_of_combustion
It is said here that
CH4 + 2O2 -> CO2 + 2H2O + energy.
What I can surmise from that is:
A: "Creating CO2" release energy, is this right?
B: "Creating H2O" release energy, is this right?
C: "Creating CH4" needs energy, is this right?
And then, there is
https://en.wikipedia.org/wiki/Standard_enthalpy_of_formation
CO2 -> -393
H2O -> -242
D: Why these numbers are minus? Is it because
"Creating CO2 (or H2O) DOES NOT need energy, but releasing instead"
Okay, if this is so, than I can (at least) take it
E: So, if producing CO2 releases energy, then PRODUCING CH4 should consume energy, is this right?
F: Methane -> -74.9. What does this mean?
Does this mean: Creating methane also RELEASES energy?
So the statements E, F and [A+B+C] seem contradictory to me.
Can anyone help?
I'd like to understand this first, before I read fermentation.
So that I can understand the benefit of composting.
Thank you very much.
I'm interested in composting.
I want to understand the benefit of composting.
Besides
- Reducing organic waste
- Producing fertilizer
I wonder how, without oxygen addition/introduction, in a sealed composter bin, can methane be synthesized?
Wiki (https://en.wikipedia.org/wiki/Fermentation) says that
CH3COO− + H+ → CH4 + CO2
Okay...
So perhaps without introducing energy from outside of the system. Methane can be synthesized.
But now I'm wondering about a new thing.
https://en.wikipedia.org/wiki/Heat_of_combustion
It is said here that
CH4 + 2O2 -> CO2 + 2H2O + energy.
What I can surmise from that is:
A: "Creating CO2" release energy, is this right?
B: "Creating H2O" release energy, is this right?
C: "Creating CH4" needs energy, is this right?
And then, there is
https://en.wikipedia.org/wiki/Standard_enthalpy_of_formation
CO2 -> -393
H2O -> -242
D: Why these numbers are minus? Is it because
"Creating CO2 (or H2O) DOES NOT need energy, but releasing instead"
Okay, if this is so, than I can (at least) take it
E: So, if producing CO2 releases energy, then PRODUCING CH4 should consume energy, is this right?
But also from the same link above: https://en.wikipedia.org/wiki/Standard_enthalpy_of_formationCH4 + 2O2 -> CO2 + 2H2O + energy.
F: Methane -> -74.9. What does this mean?
Does this mean: Creating methane also RELEASES energy?
So the statements E, F and [A+B+C] seem contradictory to me.
Can anyone help?
I'd like to understand this first, before I read fermentation.
So that I can understand the benefit of composting.
Thank you very much.