Why Combustion Is Exothermic
pubs.acs.org
Why Combustion Is Exothermic
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Re: Why Combustion Is Exothermic
#2Considering space resources people have a hard time recognizing that hydrocarbons are a structural material but not an energy source w/o molecular O2.
(e.g. it's thought that many asteroids are like Saudi Arabia but with the relative proportions of sand and hydrocarbons reversed)
Re: Why Combustion Is Exothermic
#3Considering space resources people have a hard time recognizing that hydrocarbons are a structural material but not an energy source w/o molecular O2. (e.g. it's thought that many asteroids are like Saudi Arabia but with the relative proportions of sand and hydrocarbons reversed)
I don't understand your point, if you are claiming that O2 is not abundant in space, I think the idea is that we also find an ice asteroid. Where there is water, there is oxygen.
Edit: I assume people are missing my reasoning. Yes, water requires energy to split, but assuming you are doing some other process that ends up with a resulting split anyway, you could use the hydrocarbons as a fuel source at that stage. Think recycling, not energy production.
Re: Why Combustion Is Exothermic
#4Considering space resources people have a hard time recognizing that hydrocarbons are a structural material but not an energy source w/o molecular O2. (e.g. it's thought that many asteroids are like Saudi Arabia but with the relative proportions of sand and hydrocarbons reversed)
I don't understand your point, if you are claiming that O2 is not abundant in space, I think the idea is that we also find an ice asteroid. Where there is water, there is oxygen. Edit: I assume people are missing my reasoning. Yes, water requires energy to split, but assuming you are doing some other process that ends up with a resulting split anyway, you could use the hydrocarbons as a fuel source at that stage. Thi…
Yeah but you have to expend energy to split water into hydrogen and oxygen. So burning hydrocarbons using water doesn't make much sense.
Re: Why Combustion Is Exothermic
#5Considering space resources people have a hard time recognizing that hydrocarbons are a structural material but not an energy source w/o molecular O2. (e.g. it's thought that many asteroids are like Saudi Arabia but with the relative proportions of sand and hydrocarbons reversed)
I don't understand your point, if you are claiming that O2 is not abundant in space, I think the idea is that we also find an ice asteroid. Where there is water, there is oxygen. Edit: I assume people are missing my reasoning. Yes, water requires energy to split, but assuming you are doing some other process that ends up with a resulting split anyway, you could use the hydrocarbons as a fuel source at that stage. Thi…
You can produce oxygen from water, iron ore (O'Neill and other sci-fi writers somehow missed that astronauts brought back top quality iron ore from the moon,) stony rocks, etc.
To do it from water for instance you could use electricity to split up the H2O molecules; you could directly use the resulting O2 or you could use the H2 to reduce the iron ore back to H2O and thus recycle the H2. Maybe you get electricity from solar panels or a nuclear reactor.
You could burn this with cosmic hydrocarbons but you have only accomplished energy storage as opposed to an energy source. You are then competing with a sun that shines all the time and every other energy storage technology as well as nuclear fission, fusion, and decay.
The oxygen rich environment is the gift we get from plants here on Earth, ultimately they have stored a lot of "energy" in the atmosphere which we can tap.
Future wildcatters will see asteroid hydrocarbons as the material to make human bodies and cattle, everything from wood to plastics to pharmaceuticals -- every bit as much of a gold rush, but not a new energy source.
If you could make plastics from asteroid materials you could blow very large films and coat them with layers of metals and semiconductors and thus function as solar sails if not energy collectors -- these could sail to their destinations on their own power, say to be installed at the Earth-Sun L1 point to fight global warming.
Anyhow it took people a long time to get oxygen right. Cave men "mastered" fire but people couldn't make steel commercially until people understood that 80% of the atmosphere is inert stuff that goes along for the ride.
Re: Why Combustion Is Exothermic
#6Considering space resources people have a hard time recognizing that hydrocarbons are a structural material but not an energy source w/o molecular O2. (e.g. it's thought that many asteroids are like Saudi Arabia but with the relative proportions of sand and hydrocarbons reversed)
I don't understand your point, if you are claiming that O2 is not abundant in space, I think the idea is that we also find an ice asteroid. Where there is water, there is oxygen. Edit: I assume people are missing my reasoning. Yes, water requires energy to split, but assuming you are doing some other process that ends up with a resulting split anyway, you could use the hydrocarbons as a fuel source at that stage. Thi…
Water is a product of combustion. It is what you are left with after the combustion has already happened, i.e. the oxygen has already been reduced.
Re: Why Combustion Is Exothermic
#7"−418 kJ/mol" This is one of the most useful factoids to know of the top of your head. I don't remember the actual number, and in fact I remember it (incidentally far less precise) as all hydrocarbons have about the same energy mass density.
Re: Why Combustion Is Exothermic
#8Earlier quoted context omitted.
I don't understand your point, if you are claiming that O2 is not abundant in space, I think the idea is that we also find an ice asteroid. Where there is water, there is oxygen. Edit: I assume people are missing my reasoning. Yes, water requires energy to split, but assuming you are doing some other process that ends up with a resulting split anyway, you could use the hydrocarbons as a fuel source at that stage. Thi…
You can produce oxygen from water, iron ore (O'Neill and other sci-fi writers somehow missed that astronauts brought back top quality iron ore from the moon,) stony rocks, etc. To do it from water for instance you could use electricity to split up the H2O molecules; you could directly use the resulting O2 or you could use the H2 to reduce the iron ore back to H2O and thus recycle the H2. Maybe you get electricity fro…
Wait, how do you reduce iron ore back into h2o ?
Re: Why Combustion Is Exothermic
#9Earlier quoted context omitted.
You can produce oxygen from water, iron ore (O'Neill and other sci-fi writers somehow missed that astronauts brought back top quality iron ore from the moon,) stony rocks, etc. To do it from water for instance you could use electricity to split up the H2O molecules; you could directly use the resulting O2 or you could use the H2 to reduce the iron ore back to H2O and thus recycle the H2. Maybe you get electricity fro…
Wait, how do you reduce iron ore back into h2o ?
Iron Ore is FE + O.
I forget exactly the proportions, but... the entire point of iron-processing is to turn rust back into raw Iron (FE) by removing the O from it.
Re: Why Combustion Is Exothermic
#10Wow! So the bulk of the energy we consume comes not from the hydrocarbons we're digging up, but the oxygen bonds we're breaking when we burn them. That's completely spun around my understanding of fuels. Fascinating.
That also means that the energy we use to fuel our lives mostly comes directly from recent photosynthesis, and not actually from historical sunlight embodied in the fossil fuels we're burning.