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9 Cards in this Set
- Front
- Back
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You have an ether solution that contains an organic acid, a base, and a neutral. If you extract first with aqueous acid and then with aqueous base, which organic would be in each of the extracts, and which would remain in the ether?
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With aqueous acid, organic base would be in extract and organic acid/neutral would remain
With aqueous base, organic acid would be in extract and neutral would remain |
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When you extract with two immiscible solvents in a sep funnel, it is imperative that you shake the two solvents with frequent venting. Why do you shake the two solvents together and why do you vent frequently?
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- Shaking mixes the layers, giving a good distribution of solvent/soluble
- Venting prevents pressure from building up during salt formation (as when mixing organic acid with aqueous base) ~ "burps" the funnel |
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Why is it necessary to remove the stopper when liquid is being drained from a sep funnel?
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Otherwise, the funnel won't drain
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Would you predict water or ether to be the lower phase in a sep funnel? What about a water/methylene chloride (d=1.325 g/mL) system (which solvent is the lower phase)? Why?
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Water (in water/ether); methylene chloride (in water/methylene chloride); which ever is dense goes to the bottom
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What is the difference between washing and extracting?
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Washing pulls out everything else besides what you want; for example, 'extracted' acid goes into water and through separation tunnel and is then thrown out
Extracting: pulls out what you want from everything else; ex: what you extract goes into water through separation funnel and is kept (keeps good material) |
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What would happen if the aqueous waste bucket had a lot of acid in it and a student poured in a flask of 3M NaOH?
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A dangerous eruption would occur
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ow much compound X could you extract into the ether if you extracted twice with 25 mL portions? vs. with one aliquot of 50 mL ether?
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Two 25 mL portions: 66%
One 50 mL portion: 75% |
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Why do you want to get rid of water before rotovapping?
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You need to get rid of water before rotavapping because water is a lot harder to
pull off than organic solvents, so you'll just end up with your product and water unless you really heat the bath, which could cause your product to decompose. |
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What does it mean for an organic compound to be "dry?"
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aving a dry compound can either mean having removed water
from your organic layers using sodium sulfate or magnesium sulfate or sometimes dry can mean removal of all traces of any solvent. Typically dry in the second sense is only used when referring to crystalline compounds. |
