valora
English translation: titrates.......
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| 00:44 Apr 21, 2008 |
| Spanish to English translations [PRO] Science - Chemistry; Chem Sci/Eng | |||||||
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|  Selected response from: David Brown Spain Local time: 13:29 | ||||||
Grading comment
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| Summary of answers provided | ||||
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| 5 +3 | titrates....... |
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| 3 +2 | equivalent to |
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| 4 | measures |
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| Discussion entries: 1 | |
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Answers
4 mins confidence: 
measures Explanation: In this case! |
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4 mins confidence: peer agreement (net): +2
peer agreement (net): +2equivalent to Explanation: I had a change of heart and mind... I think they are talking about equivalencey in term of titrating thioslufate with Fe3+. -------------------------------------------------- Note added at 5 mins (2008-04-21 00:50:18 GMT) -------------------------------------------------- In this case, the Fe3+ will oxidize the thiosulfate into sulfate I believe... S2O3^2- ------> SO4^2- -------------------------------------------------- Note added at 9 mins (2008-04-21 00:53:51 GMT) -------------------------------------------------- unwizard: 3.2. Homogeneous catalysis Thiosulfate ion [S2O3]2- is oxidised to tetrathionate ion [S4O6]2- by Fe3+: 2Fe3+ + 2[S2O3]2- <----> 2Fe2+ + [S4O6]2- Fill two test tubes with 4 ml 0.1 M Fe(NO3)3 solution and add to one of them 1 drop of 0.1 M Cu2+ solution. Finally, add 5 ml of 0.1 M Na2S2O3 solution to both test tubes and compare the time required for the deep color of the solutions to disappear. (Note: Fe3+ forms with thiosulfate ions a deep brown colored complex!) -------------------------------------------------- Note added at 10 mins (2008-04-21 00:54:41 GMT) -------------------------------------------------- In this particular case, the thiosulfate is oxidized to tetrathionate. It's also possible to oxidize it to sulfate... -------------------------------------------------- Note added at 17 mins (2008-04-21 01:01:30 GMT) -------------------------------------------------- Fe+3 + S2O3-- = Fe+2 + S4O6-- 2Fe+3 + 2S2O3-- = 2Fe+2 + S4O6-- Fe3+ + S2O3-- = Fe2+ + S4O6-- Apparently, the product of oxidation is tetrathionate... Here, the meaning of "equivalency" is that 0.1 ml of 0.1 M thiosulfate solution is titrated (completely reacts) with 27.03 mg of FeCl3.6H2O solution. |
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6 hrs confidence: peer agreement (net): +3
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