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CHM 322 Lab Final
N/A
114
Organic Chemistry
Undergraduate 2
12/07/2010

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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.
Definition
non-halogenated (E1)
Term
solid substances can be separated by __________ or _______
Definition
recrystallization; sublimation
Term
liquids are purified by ______
Definition
distillation
Term
in distillation, vapors have ____ of the lower-boiling component than original mixture, therefore material collected is _______
Definition
more; purer sample of lower-boiling material than original
Term
boiling stones are ________; as liquid is boiled, chips _______
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
Term
in distillation, make sure top of the bulb is _______
Definition
no higher than the lower part of the side-arm
Term
E1 distillation - temperature you are recording is the temperature of _______
Definition
the vapors
Term
E1 distillation - don’t record any temps until _________
Definition
you see vapors condensing on thermometer bulb and a drop enters vial
Term
E1 distillation - never ________
Definition
pour material to be distilled through packing material
Term
boiling point of a component is the temperature at which the temperature/volume plot is ________
Definition
nearly horizontal
Term
purpose of E1 distillation
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
Term
fractional distillation more effective b/c ________
Definition
first separates liquid with lower boiling point first, then the other liquid once all of the first has been distilled
Term
simple distillation only useful when ________ b/c ________
Definition
distilling two liquids w/ extremely different boiling points; distills all the liquid in the flask at once
Term
_______ has distinct boiling point – temp increase without significant increase in volume
Definition
fractional distillation
Term
except ________, molecules are in constant motion
Definition
at absolute zero
Term
when vapor pressure equal to atmospheric pressure, _______
Definition
liquid boils
Term
Dalton’s Law
Definition
P(A+B) – P(A) + P(B)
Term
Raoult’s Law
Definition
P(A) = PA (A pure) x X(A)
Term
mole fraction
Definition
X(A) = (moles A)/(total moles)
Term
simple distillation cannot _________
Definition
produce pure samples of the lower-boiling component
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 _________.
Definition
camphor; salicylic acid
Term
E2 The recovered salicylic acid in this experiment will be purified by __________
Definition
recrystallization
Term
two secrets to rotovap
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
Term
rotovap especially useful for _______
Definition
removing solvents from nonvolatile solutes
Term
extraction
Definition
dissolves the material we want and leaves the others behind
Term
washing
Definition
dissolves the impurities and leaves behind material we want to isolate
Term
in a solid-liquid extraction, if what you want is the liquid, use _______
Definition
gravity filtration
Term
in solid-liquid extraction, if what you want is the solid, use _______
Definition
vacuum filtration
Term
in extraction/washing, solvents must have two characteristics
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
Term
in extraction/washing, extract two/three times with small portions, not all at once
Definition
Term
test to see if it is the aqueous layer
Definition
add water and it will add to the aqueous layer
Term
telling which layer is which
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)
Term
_____ is the most common method for purifying solid compounds
Definition
recrystallization
Term
recrystallization is most successful when ________
Definition
material to be purified is insoluble in solvent when it’s cold, and much more soluble when solvent is hot
Term
trimyristin is a _________
Definition
triglyceride
Term
E4 - recrystallized trimyristin will be isolated ________
Definition
by vacuum filtration using a Hirsch funnel
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)
Definition
triglycerides
Term
_______ are identical in trimyristin
Definition
fatty acid chains
Term
fatty acid salt that forms from trimyristin is ________ and conjugate base is ________
Definition
sodium tetradecanoate/sodium myristate; myristic acid
Term
glycerol is an _________
Definition
alkanetriol
Term
fats
Definition
solid triglycerides
Term
oils
Definition
liquid triglycerides with melting points lower than that of fats
Term
saturated fats and oils don’t have any _______
Definition
C=C
Term
unsaturated fats and oils have at least one C=C; double bonds are almost always ______
Definition
Z
Term
polyunsaturated triglycerides
Definition
have more than one C=C per fatty acid side chain
Term
naturally occurring fatty acid side chains almost always have an even number of carbons and are very rarely branched b/c _____
Definition
synthesized using multiples of acetyl-CoA (which has two carbons) in a process called fatty acid biosynthesis
Term
not common to analyze fats and oils without breaking them down because ________
Definition
have such low volatilities
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?
Definition
tetrahydrofuran
Term
E5 synthesis of a bromohydrin - What is the correct name of the alkene starting material that will be used in this experiment?
Definition
1-methylcyclohexene
Term
addition reaction #1 bromohydroxylation/Bromohydrin formation
Definition
where A-B is Br-OH
Term
addition reaction #1 bromohydroxylation/Bromohydrin formation
Definition
where A-B is Br-OH
Term
addition reaction #2 hydrogenation
Definition
where A-B is H-H, results in alkane product
Term
addition reaction #3 Diels-Alder reaction
Definition
where A-B is a alkadiene, results in new carbon-carbon bonds, results in cyclohexane product
Term
in E5, used _______ for source of bromine
Definition
N-bromosuccinimide (NBS)
Term
column chromatography is a 3D version of _____
Definition
thin layer chromatography from E4
Term
use column chromatography to isolate compounds based on __________
Definition
relative polarities
Term
E5 - crude product results in 50:50 mixture of _________
Definition
2-bromo-1-methylcyclohexanol (which we want) and succinimide (which we don’t)
Term
idea behind column chromatography
Definition
more polar compound sticks to polar silica gel and moves down more slowly than less polar compound
Term
infrared spectroscopy: relies on fact that ________
Definition
chemical bonds behave like springs – if stretched or deformed, atoms connect by bonds will vibrate
Term
bond stretches require ______ infrared energies to occur and appear at ________ frequencies
Definition
higher; higher
Term
bond bends require _____ infrared energies to occur and appear at ______ frequencies
Definition
lower; lower
Term
once some of the heat is absorbed, chemical bonds and their atoms can be found to _______
Definition
vibrate in a number of predictable ways
Term
the heavier the atoms connected by a chemical bond, the ________
Definition
lower the frequency at which the bond will stretch
Term
_______ stretch at higher frequencies than ________
Definition
strong bonds; weaker bonds
Term
IR frequency of OH: alcohols and phenols
Definition
3650-3200 m
Term
IR frequency of OH: carboxylic acids
Definition
3400-2400 m
Term
IR frequency of sp2 C=C: alkenes
Definition
1680-1600 m-w
Term
IR frequency of sp2 C=C: aromatics
Definition
1600 & 1475 m-w
Term
IR frequency of sp2 C-H: alkenes (stretch)
Definition
3100-3000 m
Term
IR frequency of sp2 C-H: aromatics (stretch)
Definition
3150-3050 s
Term
E6 - The metal catalyst that facilitates the formation of hydrogen from the hydrogen donor reagent in this experiment is __________
Definition
palladium
Term
purpose of E6
Definition
purpose of this lab is to hydrogenate an alkene (oleic acid) into an alkane (stearic acid)
Term
hydrogen donor in E6
Definition
ammonium formate
Term
E6 permanganate test
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)
Term
E6 - alkene is _____, which becomes a solid carboxylic acid, ______
Definition
oleic acid; stearic acid
Term
E7 purpose
Definition
use a modern form of ozonolysis to determine structure of starting cinnamic acid used
Term
reagents used in E7
Definition
take nitrocinnamic acid, add CH2Cl2, add alumina-supported potassium permanganate; remove methylene chloride through rotovap
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).
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.
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?
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.
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
Definition
more
Term
component’s partial pressure depends on ________
Definition
concentration of the material present in the liquid and vapor pressure of pure substance
Term
vapor pressure, boiling point, and composition of the vapor with which it is in equilibrium depend on ________
Definition
liquid’s composition
Term
vapor has a larger fraction of the ________ than the liquid does
Definition
more volatile (lower-boiling) component
Term
when a mixture boils, vapor will contain __________
Definition
both components, but will be richer in the more volatile component than the liquid was
Term
since the liquid remaining in the pot becomes richer and richer in the higher-boiling component as the simple distillation continues, _______
Definition
its boiling point rises too
Term
boiling point of mixture rises during distillation as _________
Definition
remaining liquid becomes richer and richer in the higher-boiling component, and distillate becomes less and less rich in lower-boiling component
Term
temp in a distillation measures ______
Definition
temp of the vapor which we collect, not necessarily the boiling point of the liquid mixture
Term
in an ideal fractional distillation, ________
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
Term
temp expected to ______ as distillation continues
Definition
increase
Term
acid-base extraction
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
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?
Definition
5.1
Term
E4 purpose
Definition
isolate trimyristin (a saturated fat) by using dichloromethane (a liquid solvent) to extract it from ground nutmeg
Term
E4 - purify it by
Definition
recrystallization
Term
common to analyze fats and oils by ______, then replace glycerol with methanol to form 3 methyl esters of constituent fatty acids
Definition
saponification; ester can be separated and identified with gas chromatography; called fatty acid methyl ester (FAME) determinations
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?
Definition
66
Term
generic synthesis reaction
Definition
C=C + A-B -> A-C-C-B
Term
in this reaction, C=C + A=B -> A=C + B=C, most common things eliminated are ______
Definition
HCl, HBr and H2O (dehydration)
Term
electrophilic additions to Π bonds regioselective _________
Definition
Markovnikov (bromohydroxylation) or anti-Markovnikov (hydroboration-oxidation)

syn (hydrogenation) or anti (bromohydroxylation)
Term
synthesis of a bromohydrin
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
Term
E5 tests to confirm identity of product - IR spectrum
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
Term
E5 tests to confirm identity of product - Beilstein test
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
Term
E5 tests to confirm identity of product - Jones test
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
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?
Definition
82
Term
E6 steps and reagents
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
Term
E6 overall reaction
Definition
[image]
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?
Definition
ozone, O3
Term
What is the identity of Y?
Definition
[image]
Term
E7 overall reaction
Definition
[image]
Term
impurity's affect on melting point
Definition
lower melting point and wider melting point range - provides an assessment of purity
Term
Why is cellulose insoluble in CH2Cl2?
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.
Term
four techniques that may be used to induce crystal formation during recrystallization
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
Term
salicyclic acid is _______ in CH2Cl2
Definition
infinitely soluble
Term
salicylic acid is ______ in water
Definition
sparingly soluble
Term
salicylic acid does or does not extract into 1M NaOH
Definition
does
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