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Politics : Stockman Scott's Political Debate Porch

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To: Jim Willie CB who wrote (5332)	8/28/2002 6:50:22 PM
From: yard_man	Read Replies (2) of 89467

this is what I was trying to get to in talking about hydrolysis -- seems to me you need the same energy input to separate the H from the O that you would get from the recombination -- so it comes down to nothing more than a glorified enery storage device. >> Question - How much energy does it take to overcome the "barrier" to seperate hydrogen and oxygen and are there catalists that can make the process more efficient? ---------------------------- Eugene, When gaseous hydrogen is burned in gaseous oxygen to make gaseous water: H2 + 1/2O2 ===> H20 242 kJ energy is released for every released mole (18 grams) of water produced. The same amount of energy must be input to drive the reaction backwards to produce hydrogen and oxygen from water in the gaseous state. Scientists are working to discover a means by which the process can be accomplished more efficiently and economically. Nevertheless, whether accomplished with catalysts or via some biological method, the energy input required remains the same. Science is constrained by the laws of thermodynamics. Regards, ProfHoff ========================================================= This question is not quite specific enough. It has two possible meanings: 1. The separation of a gaseous mixture of H2 and O2 gas: Because of the difference in the size and diffusion properties, no doubt a membrane permeable to H2 but not to O2 could be engineered, and the only energy necessary would be to keep the pressure on the gaseous mixture. 2. The formation of H2 and O2 from liquid H2O: I suspect that this is the context of the question. If it is the work (free energy) required to decompose 1 mol of liquid water (about 18 cm^3) into gaseous H2 and O2 at 1 atm pressure and 25 C. is 56.7k-cal/mol H2O). There are catalysts that promote this reaction, e.g. Pt powder, but that does not change the energy requirements, which are substantial. Vince Calder <<

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