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Thread ID: 111753	2010-08-10 07:13:00	Chemistry Help!	xyz823 (13649)	PC World Chat

Post ID	Timestamp	Content	User
1126336	2010-08-10 08:03:00	You don't have any free electrons in a balanced redox equation! Sans the electrons lol. Well spotted, thanks :)	Renmoo (66)
1126337	2010-08-10 08:06:00	H2O + HSO3 (-1) -2e = SO4 (-2) + 3H(+1) Fe (+3) + e = Fe(+2) H20 + HSO3 + 2 Fe (+3) = SO4 (-2) + 2Fe(+2) + 3H(+1) Colour change from yellow/brown to pale green My chemistry is a little rusty though... Correct me if I'm wrong but, Don't you add electrons on to the left hand side of one half equation and add electrons the the right hand side of the other one? Meaning you would have to leave the hydrogen out giving this... SO3 (-1) + H2O = SO4 (-2) + 2H (+1) + e Fe (+3) + e = Fe (+2) SO3 (-1) + H2O + Fe (+3) = SO4 (-2) + 2H (+1) + Fe (+2) If I'm wrong don't hesitate to correct me!	xyz823 (13649)
1126338	2010-08-10 08:10:00	SO3 (-1) + H2O = SO4 (-2) + 2H (+1) + e It is HSO3(-1) The hydrogen is part of the entity. Na+ is left out.	Renmoo (66)
1126339	2010-08-10 08:15:00	Correct me if I'm wrong but, Don't you add electrons on to the left hand side of one half equation and add electrons the the right hand side of the other one? Meaning you would have to leave the hydrogen out giving this... SO3 (-1) + H2O = SO4 (-2) + 2H (+1) + e Fe (+3) + e = Fe (+2) SO3 (-1) + H2O + Fe (+3) = SO4 (-2) + 2H (+1) + Fe (+2) If I'm wrong don't hesitate to correct me! You have mistakenly written the bisulphite ion as SO3- instead of HSO3- This accounts for the 3H+ on the RHS. It does not matter whether you have electrons added on the left and right of the respective half reactions, it is the same overall if you subtract them from the half equation showing the oxidation. As long as everything balances in the end (like an algebra equation).	user (1404)
1126340	2010-08-10 08:15:00	SO3 (-1) + H2O = SO4 (-2) + 2H (+1) + e It is HSO3(-1) The hydrogen is part of the entity. Na+ is left out. Ohk. Pretty sure I get it.	xyz823 (13649)
1126341	2010-08-10 19:56:00	Once again we need to salute the collective wisdom of those haunting these forums. For me this has served as a reminder of what a nightmare I found chemistry, and of how much I've forgotten over the last 25 years. I was at a loss to post anything useful, and probably would still have struggled to answer this 25 years ago when the teaching was still fresh in my mind.	Paul.Cov (425)
1126342	2010-08-10 20:23:00	B*gger. Saw this question and thought "hmmmm, should be easy meat" because one of my majors at Uni was Chemistry. Suffering succotash, I could not remember a frickin thing - 'tis probably true what they say, use it or lose it. sarel	sarel (2490)
1126343	2010-08-10 21:46:00	www.studyit.org.nz Great website that I use to frequent every half a day five years ago. The tutors over there > my teachers in high school. Especially with Biology :stare:	Renmoo (66)
1126344	2010-08-10 21:47:00	www.studyit.org.nz Great website that I use to frequent every half a day five years ago. The tutors over there > my teachers in high school.	Renmoo (66)
1126345	2010-08-10 22:06:00	Must admit I struggled working through the question, but been early 80's since I graduated in chemistry. I recall the charge transfer transition state? and/or ligand field theory that causes the colour change? I also thought that double arrows are used for equilibrium rather than the = sign? Because Cl and Na are present what prevents (or could induce) them from precipitating/forming a salt solution?	kahawai chaser (3545)
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