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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
1126356	2010-08-11 01:42:00	Cheers guys, just wasn't sure what was actually being reduced and what was being oxidised! Got myself all confused :/ LEO (the lion) goes GER! Meaning LEO = Loss of Electrons = Oxidation GER = Gain of Electrons = Reduction hth :)	SoniKalien (792)
1126357	2010-08-11 01:42:00	Note the negative sign posted by user. Hmm we havnt been over that yet, only adding things. Whats the difference? Presume its just the opposite though?	xyz823 (13649)
1126358	2010-08-11 03:08:00	Hmm we havnt been over that yet, only adding things. Whats the difference? Presume its just the opposite though? Yup! It's like: 3 - 2 = 1 3 = 1 + 2	Renmoo (66)
1126359	2010-08-11 03:10:00	Hmm we havnt been over that yet, only adding things. Whats the difference? Presume its just the opposite though? That is simply the way I taught it many years ago. Logical since oxidation is the loss of electrons so it appears as a minus electrons on the LHS, reduction is the gain so it appears as a plus electrons on the RHS. I think the ferrous ion probably has 6 water ligands surrounding it in solution. The common ion effect would have no practical effect in causing NaCl to ppt in the redox reaction under discussion. It is far too soluble for any effect to show under the concentrations normally encountered. As an aside, ferrous sulphate was known as green vitriol. Heating the salt over a flame produces sulphur trioxide, which can be dissolved in water to form oil of vitriol or sulphuric acid. I think this was how the acid was first produced, thus its old name. (If memory serves me correct - not to imply that I was around at the time of discovery though)	user (1404)
1126360	2010-08-12 07:12:00	Since user has answered the first half of the question, I will attempt to explain the second half. Common ion effect - The addition of either positive ions or negative ions can induce precipitation. The presence of NaCl salt in solution has the following equilibrium: NaCl (s) < = > Na+(l) + Cl-(l) Where s = solid, l = liquid. When more of the positive ions or negative ions are added to the solution, it can push the equilibrium towards the left side (Le Chatelier's principle), whereby the ions are induced to form the solid form again. Cheers :) OK - Thanks. Must reach it's saturation point, based on solubility product (I think) when crystals form.	kahawai chaser (3545)
1126361	2010-08-15 06:13:00	Going through some more similar questions, came across this one here. Hydrogen Peroxide is reacted with Iron(II) Sulfate. Write the reaction and the observations. Water is a product. Any help would be much appreciated. I presume that the Iron (II) is reduced to Iron (III)? But not quite sure what is being oxidised etc.	xyz823 (13649)
1126362	2010-08-15 06:24:00	H2O2 + 2H+ + 2e- = H2O + H2O (i.e. two H2O molecules being produced) Fe2+ = Fe3+ + e 2Fe2+ = 2Fe3+ + 2e Now you can "add" both half equations H2O2 + 2H+ + 2Fe2+ = 2H2O + 2Fe3+	Renmoo (66)
1126363	2010-08-15 06:27:00	Regarding this query: But not quite sure what is being oxidised etc. In a redox reaction, when a compound is reduced, the other participating compound must have been reduced. Since you have made the guess that Ferrous Sulphate would be oxidised to Ferric Sulphate, therefore hydrogen peroxide must undergo a reduction reaction. You know water is the product: H2O2 = H2O Balance the oxygen first: H2O2 = H2O + H2O Balance the hydrogen now by adding H+ to the left side: H2O2 + 2H+ = H2O + H2O Now balance the charges by adding the correct number of electrons: H2O2 + 2H+ + 2e = 2H2O :)	Renmoo (66)
1126364	2010-08-15 06:31:00	H2O2 + 2H+ + 2e- = H2O + H2O (i.e. two H2O molecules being produced) Fe2+ = Fe3+ + e 2Fe2+ = 2Fe3+ + 2e Now you can "add" both half equations H2O2 + 2H+ + 2Fe2+ = 2H2O + 2Fe3+ Cheers. So the H2O2 is oxidised to two H2O molecules?	xyz823 (13649)
1126365	2010-08-15 07:01:00	Yes	Renmoo (66)
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