dijinj Posted May 28, 2014 Posted May 28, 2014 (edited) Er, no. Have you ever seen sodium hit water before? It's pretty exothermic. Perhaps you should avoid answering questions if you're unsure of them yourself. OP: Do you require numerical answers for delta H or something? You haven't provided enough information to do that, if so. Some clarification on the exact question and the information you are given would be helpful here. if both reactions are exothermic. then is this a free energy(not Gibbs free energy) method to split water. first reaction gives OH and second reaction gives H2 and NaOH is recycled and we will get heat energy as bonus. Can somebody give enthalpy of formation (del H f)to show that this reactions are truly exothermic or is there any catch like you cant separate Na+ and OH- from H2O (in the first reaction) Edited May 28, 2014 by dijinj
hypervalent_iodine Posted May 28, 2014 Posted May 28, 2014 if both reactions are exothermic. then is this a free energy(not Gibbs free energy) method to split water. first reaction gives OH and second reaction gives H2 and NaOH is recycled and we will get heat energy as bonus. Can somebody give enthalpy of formation (del H f)to show that this reactions are truly exothermic or is there any catch like you cant separate Na+ and OH- from H2O (in the first reaction) Also definitely not. Na+ =/= Na . Please look up what enthalpy is and unofficially, could people please stop posting complete bunk in response to this thread? Keep the speculations in the appropriate section.
dijinj Posted May 29, 2014 Author Posted May 29, 2014 (edited) is there any way to separate "Na+" from NaOH and H2O solution, like electrolysis, electromagnetic or electrostatic etc. I think Coulomb forces between Na+ and OH- will be the bottleneck to separate them Edited May 29, 2014 by dijinj
dijinj Posted May 30, 2014 Author Posted May 30, 2014 Prime concern is to recycle NaOH, so if nacent Na reacts with H2O and form NaOH is no problem. But it should not burn the apparatus and burn H2(side product from that reaction) . Making H2 is most important
Fuzzwood Posted May 30, 2014 Posted May 30, 2014 Prime concern is how you would regenerate Na which requires more energy than what you ever could get from oxidizing H2.
dijinj Posted May 30, 2014 Author Posted May 30, 2014 http://www.scienceforums.net/topic/37193-no-you-cant-make-sodium/ in the above discussion it says that Na could be deposited on electrode and immediately reacts with water to form NaOH. from my knowledge, dissolution of NaOH and reacting Na with H2O; both are exothermic. if my memory serves correctly the forming elements from its ions is also exothermic ( or produce electric potential). so how does this whole set of reactions are not favorable to produce H2 and OH in concern with energy balance. in first look it seems like a free energy device to produce hydrogen. please reply with supporting evidence like links, sci paper or references
John Cuthber Posted May 30, 2014 Posted May 30, 2014 http://www.scienceforums.net/topic/37193-no-you-cant-make-sodium/ in the above discussion it says that Na could be deposited on electrode and immediately reacts with water to form NaOH. from my knowledge, dissolution of NaOH and reacting Na with H2O; both are exothermic. if my memory serves correctly the forming elements from its ions is also exothermic ( or produce electric potential). so how does this whole set of reactions are not favorable to produce H2 and OH in concern with energy balance. in first look it seems like a free energy device to produce hydrogen. please reply with supporting evidence like links, sci paper or references What if your memory doesn't serve?
dijinj Posted May 31, 2014 Author Posted May 31, 2014 John Cuthber can you please be more specific on subject, what I learned is ionization needs energy, so De-ionization releases energy. is this correct in Na+ s case?
hypervalent_iodine Posted May 31, 2014 Posted May 31, 2014 Could you please stop derailing the thread?
John Cuthber Posted May 31, 2014 Posted May 31, 2014 John Cuthber can you please be more specific on subject, what I learned is ionization needs energy, so De-ionization releases energy. is this correct in Na+ s case? It depends on the circumstances. It's true in the gas phase, but not in solution. Anyway, you can't get free energy out of it so there's no point in talking about that and, as hypervalent iodine says, derailing the thread.
dijinj Posted June 1, 2014 Author Posted June 1, 2014 (edited) what is different in solution case, is the Coulomb forces are the obstacle. how to calculate energy balance in such cases? In water solution Na+ will be surrounded by polar H2O molecule in one way and OH- will be surrounded by polar H2O molecule by other way; all these are in equilibrium. To separate Na+ we should break this equilibrium and Coulomb forces between +ve and -ve ions will be the obstacle. can you give good references with worked out example to calculate energy balance of such system Edited June 1, 2014 by dijinj
John Cuthber Posted June 1, 2014 Posted June 1, 2014 It's possible to calculate the energy balances involved, but I don't plan to waste my time doing it. I know it's a waste of time because what you are proposing is "free energy" and that's impossible. If you insist on doing the mathematics, even though you already know it won't work, this is probably a good place to start http://en.wikipedia.org/wiki/Debye%E2%80%93H%C3%BCckel_theory If, when you have done the maths, you think you have got more energy than you put in, do them maths again because you have made a mistake.
dijinj Posted June 2, 2014 Author Posted June 2, 2014 (edited) thanks. I think I should at-least do one round of calculation to satisfy my quest Edited June 2, 2014 by dijinj
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now