Term
| If the "recovered toluene-cyclohexane mixture" container is not available in lab, an appropriate alternative to dispose of the toluene-cyclohexane waste is the ___________ waste. |
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Definition
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Term
| solid substances can be separated by __________ or _______ |
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Definition
| recrystallization; sublimation |
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Term
| liquids are purified by ______ |
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Definition
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Term
| in distillation, vapors have ____ of the lower-boiling component than original mixture, therefore material collected is _______ |
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Definition
| more; purer sample of lower-boiling material than original |
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Term
| boiling stones are ________; as liquid is boiled, chips _______ |
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Definition
| porous material which have air trapped in their cavitiesrelease a steam of tiny bubbles which agitate the mixture and break up larger bubbles in the liquid |
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Term
| in distillation, make sure top of the bulb is _______ |
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Definition
| no higher than the lower part of the side-arm |
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Term
| E1 distillation - temperature you are recording is the temperature of _______ |
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Definition
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Term
| E1 distillation - don’t record any temps until _________ |
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Definition
| you see vapors condensing on thermometer bulb and a drop enters vial |
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Term
| E1 distillation - never ________ |
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Definition
| pour material to be distilled through packing material |
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Term
| boiling point of a component is the temperature at which the temperature/volume plot is ________ |
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Definition
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Term
| purpose of E1 distillation |
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Definition
| to perform two distillations of a mixture of toluene and cyclohexane (simple and fractional), compare efficiency, and perform a third distillation as a means of identifying an unknown mixture |
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Term
| fractional distillation more effective b/c ________ |
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Definition
| first separates liquid with lower boiling point first, then the other liquid once all of the first has been distilled |
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Term
| simple distillation only useful when ________ b/c ________ |
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Definition
| distilling two liquids w/ extremely different boiling points; distills all the liquid in the flask at once |
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Term
| _______ has distinct boiling point – temp increase without significant increase in volume |
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Definition
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Term
| except ________, molecules are in constant motion |
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Definition
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Term
| when vapor pressure equal to atmospheric pressure, _______ |
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Definition
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Term
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Definition
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Term
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Definition
| P(A) = PA (A pure) x X(A) |
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Term
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Definition
| X(A) = (moles A)/(total moles) |
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Term
| simple distillation cannot _________ |
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Definition
| produce pure samples of the lower-boiling component |
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Term
| E2 - The Nutz2Wartz powder you will use in this experiment is a mixture of cellulose, camphor and salicylic acid. When methylene chloride is added to the mixture, the components that dissolve are __________ and _________. |
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Definition
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Term
| E2 The recovered salicylic acid in this experiment will be purified by __________ |
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Definition
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Term
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Definition
(1) increase surface area of solution you are distilling
(2) perform distillation at reduced pressure by evacuating the distillation apparatus with a water aspirator |
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Term
| rotovap especially useful for _______ |
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Definition
| removing solvents from nonvolatile solutes |
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Term
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Definition
| dissolves the material we want and leaves the others behind |
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Term
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Definition
| dissolves the impurities and leaves behind material we want to isolate |
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Term
| in a solid-liquid extraction, if what you want is the liquid, use _______ |
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Definition
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Term
| in solid-liquid extraction, if what you want is the solid, use _______ |
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Definition
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Term
| in extraction/washing, solvents must have two characteristics |
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Definition
(1) capable of extracting desired material from original solution while leaving undesirable material behind or vise versa
(2) two solutions must be insoluble in each other (immiscible); most organic solvents are miscible in each other; methanol, ethanol, dimethylsulfoxide and acetone not used b/c miscible with water |
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Term
| in extraction/washing, extract two/three times with small portions, not all at once |
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Definition
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Term
| test to see if it is the aqueous layer |
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Definition
| add water and it will add to the aqueous layer |
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Term
| telling which layer is which |
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Definition
lower layer will always be more dense; densities will be close to density of pure solvent; density of water is 1.0 g/mL, so density of aqueous solution close to 1.0 g/mL too
(acids and bases we use are aqueous) |
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Term
| _____ is the most common method for purifying solid compounds |
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Definition
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Term
| recrystallization is most successful when ________ |
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Definition
| material to be purified is insoluble in solvent when it’s cold, and much more soluble when solvent is hot |
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Term
| trimyristin is a _________ |
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Definition
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Term
| E4 - recrystallized trimyristin will be isolated ________ |
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Definition
| by vacuum filtration using a Hirsch funnel |
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Term
| fats and oils belong to class called _______, which are derived from a glycerol core, with three fatty acid chains attached (chains can be identical) |
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Definition
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Term
| _______ are identical in trimyristin |
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Definition
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Term
| fatty acid salt that forms from trimyristin is ________ and conjugate base is ________ |
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Definition
| sodium tetradecanoate/sodium myristate; myristic acid |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| liquid triglycerides with melting points lower than that of fats |
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Term
| saturated fats and oils don’t have any _______ |
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Definition
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Term
| unsaturated fats and oils have at least one C=C; double bonds are almost always ______ |
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Definition
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Term
| polyunsaturated triglycerides |
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Definition
| have more than one C=C per fatty acid side chain |
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Term
| naturally occurring fatty acid side chains almost always have an even number of carbons and are very rarely branched b/c _____ |
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Definition
| synthesized using multiples of acetyl-CoA (which has two carbons) in a process called fatty acid biosynthesis |
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Term
| not common to analyze fats and oils without breaking them down because ________ |
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Definition
| have such low volatilities |
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Term
| E5 synthesis of a bromohydrin - In addition to water, which serves as both a reactant and a co-solvent, what is the name of the other co-solvent used in this reaction? |
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Definition
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Term
| E5 synthesis of a bromohydrin - What is the correct name of the alkene starting material that will be used in this experiment? |
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Definition
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Term
| addition reaction #1 bromohydroxylation/Bromohydrin formation |
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Definition
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Term
| addition reaction #1 bromohydroxylation/Bromohydrin formation |
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Definition
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Term
| addition reaction #2 hydrogenation |
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Definition
| where A-B is H-H, results in alkane product |
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Term
| addition reaction #3 Diels-Alder reaction |
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Definition
| where A-B is a alkadiene, results in new carbon-carbon bonds, results in cyclohexane product |
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Term
| in E5, used _______ for source of bromine |
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Definition
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Term
| column chromatography is a 3D version of _____ |
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Definition
| thin layer chromatography from E4 |
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Term
| use column chromatography to isolate compounds based on __________ |
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Definition
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Term
| E5 - crude product results in 50:50 mixture of _________ |
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Definition
| 2-bromo-1-methylcyclohexanol (which we want) and succinimide (which we don’t) |
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Term
| idea behind column chromatography |
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Definition
| more polar compound sticks to polar silica gel and moves down more slowly than less polar compound |
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Term
| infrared spectroscopy: relies on fact that ________ |
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Definition
| chemical bonds behave like springs – if stretched or deformed, atoms connect by bonds will vibrate |
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Term
| bond stretches require ______ infrared energies to occur and appear at ________ frequencies |
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Definition
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Term
| bond bends require _____ infrared energies to occur and appear at ______ frequencies |
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Definition
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Term
| once some of the heat is absorbed, chemical bonds and their atoms can be found to _______ |
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Definition
| vibrate in a number of predictable ways |
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Term
| the heavier the atoms connected by a chemical bond, the ________ |
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Definition
| lower the frequency at which the bond will stretch |
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Term
| _______ stretch at higher frequencies than ________ |
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Definition
| strong bonds; weaker bonds |
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Term
| IR frequency of OH: alcohols and phenols |
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Definition
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Term
| IR frequency of OH: carboxylic acids |
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Definition
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Term
| IR frequency of sp2 C=C: alkenes |
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Definition
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Term
| IR frequency of sp2 C=C: aromatics |
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Definition
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Term
| IR frequency of sp2 C-H: alkenes (stretch) |
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Definition
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Term
| IR frequency of sp2 C-H: aromatics (stretch) |
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Definition
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Term
| E6 - The metal catalyst that facilitates the formation of hydrogen from the hydrogen donor reagent in this experiment is __________ |
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Definition
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Term
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Definition
| purpose of this lab is to hydrogenate an alkene (oleic acid) into an alkane (stearic acid) |
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Term
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Definition
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Term
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Definition
| test for presence of double bonds by oxidizing them; add acetone and mix; add potassium permanganate; result of test for starting alkene constitutes a positive permanganate test; if double bond of starting alkene has been successfully reduced, should not give a positive test; stearic acid was purpose the whole time; oleic acid started off as purple, then became brown (positive test) |
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Term
| E6 - alkene is _____, which becomes a solid carboxylic acid, ______ |
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Definition
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Term
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Definition
| use a modern form of ozonolysis to determine structure of starting cinnamic acid used |
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Term
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Definition
| take nitrocinnamic acid, add CH2Cl2, add alumina-supported potassium permanganate; remove methylene chloride through rotovap |
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Term
| Explain using chemical bonding and polarity concepts why the boiling point of water (100 °C) is much higher than that of hexane (69 °C). |
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Definition
| Since hexane consists entirely of C-H bonds (nonpolar), the electrons shared equally between C&H. In water, O more electronegative, so electrons spend most of their time on O. Since water is polar, forms hydrogen bonds to itself, which must be broken before molecule itself can be broken down, requiring more energy. |
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Term
| If you were to separate a mixture of 1,2-dichloroethane (b.pt. 83 °C) and 2-methylhexane (b.pt. 90 °C), what type of distillation would you use and why? |
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Definition
| Fractional b/c simple distillation only valuable when boiling points are much farther apart. Fractional allows each liquid to be boiled off separately. provides more precise graphs. |
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Term
| in distillation, if components of the mixture have different vapor pressures, condensed vapor (distillate) will contain ______ of the volatile component (one with lower boiling point) than original mixture did |
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Definition
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Term
| component’s partial pressure depends on ________ |
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Definition
| concentration of the material present in the liquid and vapor pressure of pure substance |
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Term
| vapor pressure, boiling point, and composition of the vapor with which it is in equilibrium depend on ________ |
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Definition
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Term
| vapor has a larger fraction of the ________ than the liquid does |
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Definition
| more volatile (lower-boiling) component |
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Term
| when a mixture boils, vapor will contain __________ |
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Definition
| both components, but will be richer in the more volatile component than the liquid was |
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Term
| since the liquid remaining in the pot becomes richer and richer in the higher-boiling component as the simple distillation continues, _______ |
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Definition
| its boiling point rises too |
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Term
| boiling point of mixture rises during distillation as _________ |
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Definition
| remaining liquid becomes richer and richer in the higher-boiling component, and distillate becomes less and less rich in lower-boiling component |
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Term
| temp in a distillation measures ______ |
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Definition
| temp of the vapor which we collect, not necessarily the boiling point of the liquid mixture |
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Term
| in an ideal fractional distillation, ________ |
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Definition
| first drop will distill at boiling point of the more volatile component and temp will remain stable until all of that component has been distilled |
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Term
| temp expected to ______ as distillation continues |
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Definition
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Term
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Definition
| aqueous acid used to extract organic bases from organic solutions; aqueous base used to extract organic acids from their solutions; as two solutions shaken together, acid and base react to form a salt; since salt ionic, salt extracted into aqueous phase and can be separate from other components, which remain behind in organic phase; after solutions separated, aqueous layer is neutralized, regenerating organic base or acid, which is insoluble in water |
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Term
| If 1.12 g of crude cocaine (MW = 303.35 g/mol) is isolated from 22 g of coca leaves, what is percent recovery of crude cocaine from the coca leaves? |
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Definition
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Term
|
Definition
| isolate trimyristin (a saturated fat) by using dichloromethane (a liquid solvent) to extract it from ground nutmeg |
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Term
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Definition
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Term
| common to analyze fats and oils by ______, then replace glycerol with methanol to form 3 methyl esters of constituent fatty acids |
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Definition
| saponification; ester can be separated and identified with gas chromatography; called fatty acid methyl ester (FAME) determinations |
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Term
| If you started with 1.1 mmol of 1-methylcyclohexene (MW 96.17 g/mol) and synthesized 0.14 g of 1-methyl-2-bromocyclohexanol (MW 193.08 g/mol), what is the percent yield of the product? |
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Definition
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Term
| generic synthesis reaction |
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Definition
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Term
| in this reaction, C=C + A=B -> A=C + B=C, most common things eliminated are ______ |
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Definition
| HCl, HBr and H2O (dehydration) |
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Term
| electrophilic additions to Π bonds regioselective _________ |
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Definition
Markovnikov (bromohydroxylation) or anti-Markovnikov (hydroboration-oxidation)
syn (hydrogenation) or anti (bromohydroxylation) |
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Term
| synthesis of a bromohydrin |
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Definition
| add NBS, then distilled water, THF and 1-methylcyclohexene; dry with anhydrous magnesium sulfate; fill chromatography column with silica gel; rinse test tube with methylene chloride; remove solvent through rotovap |
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Term
| E5 tests to confirm identity of product - IR spectrum |
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Definition
| confirm that alkene functional group isn’t present anymore; should no longer see C sp2-H (w) stretching band at 3040, C sp2-C sp2 (w) stretching band at 1680, or trisubstituted C=C (s) bending band at 795; should see O-H (s) stretching band at 3400 |
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Term
| E5 tests to confirm identity of product - Beilstein test |
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Definition
| put liquid on copper wire; can compare with methylene chloride, which has very obvious positive test (bright blue-green flame); saw blue-green flame |
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Term
| E5 tests to confirm identity of product - Jones test |
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Definition
| combine 1 drop product and acetone; add Jones reagent; if positive for secondary alcohol, anti-Markovnikov addition product, green within 5-10 seconds; if negative, alcohol is tertiary, Markovnikov addition product, orange-red; stayed rust/red-orange |
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Term
| 1.2 millimoles of oleic acid (MW 282.48 g/mol) was submitted to transfer hydrogenation, and 0.28 g of pure stearic acid (MW 284.48 g/mol) was obtained from the reaction. What is the percent yield of this reaction? |
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Definition
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Term
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Definition
| need a finely divided metal catalyst to donate hydrogen – ammonium formate (decomposes in presence of palladium); add oleic acid, methanol, and Pd/C; add ammonium formate; vacuum filter with methanol; add H2SO4 and CH2Cl2 to filtrate; dry with anhydrous sodium sulfate |
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Term
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Definition
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Term
| Will use potassium permanganate, KMnO4, supported on alumina, Al2O3, to oxidize an alkene in experiment 7. What other chemical reagent is commonly used to perform this type of oxidation? |
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Definition
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Term
| What is the identity of Y? |
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Definition
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Term
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Definition
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Term
| impurity's affect on melting point |
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Definition
| lower melting point and wider melting point range - provides an assessment of purity |
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Term
| Why is cellulose insoluble in CH2Cl2? |
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Definition
| cellulose is polar. as a result of the large number of functional groups on cellulose, it is attracted to other molecules of cellulose. this strong desire to connect can't be broken by a relatively nonpolar solvent such as methylene chloride. |
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Term
| four techniques that may be used to induce crystal formation during recrystallization |
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Definition
| (1) cool solution in ice bath (2) scratch wall with glass stir rod (3) add very small amount of solid material (4) heat solution back to boiling and boil off some of solvent - increase concentration of solution, then allow to cool |
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Term
| salicyclic acid is _______ in CH2Cl2 |
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Definition
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Term
| salicylic acid is ______ in water |
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Definition
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Term
| salicylic acid does or does not extract into 1M NaOH |
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Definition
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