Ochem Lab Exam
The naphthalate anion is in the _____ phase
aqueous
In the phase transfer catalysis experiment, the top layer is _____ and contains ______.
aqueous layer, water, sodium 2-naptholate, sodium hydroxide, benzyltributylammonium chloride
In the oxidation of secondary alcohols, the top layer was ___ and contained ____ and ___
aqueous, water, sodium chloride
1,3 diaxial interactions
are steric interactions between an axial substituent located on carbon atom 1 of a cyclohexane ring and the hydrogen atoms (or other substituents) located on carbon atoms 3 and 5
In GC, the amount of sample detected is proportional to the peak ___
area
use safety shower when spills cover more than student's _____
arms
a highly polar solvent will lead to nonpolar solute crowding ____ leading to decreased seperation between compound.
at the solvent front
eclisped conformation newman projection
atoms along same line of sight
Why would the reaction fail to work if the solvent was switched to ehtanol inthe phase transfer catalysis experiment?
because the base would deprotonate ehtanol and create a second nucleophile.
Mark the plate _____ applying the sample
before
One should recover the benzocaine ______ extracting benzoic acid
before
disconnect the tubing ______ turning off the water
before
For TLC, the solvent level should be ____ the spots.
below
What was the mixture of the extraction lab composed of?
benzocaine/benzoic acid
the denser liquid is on the _____ layer
bottom
When assembling an apparatus with clamps always start from the _____
bottom up
for the condensor, the _____ tube should be connected to the water source and the _____ tube placed into the drain.
bottom, upper
Azeotropes _____ be separated by simple distillation.
cannot
IR spctroscopy ______ analyze samples that are complex mixtures.
cannot
materials with different TLC values __________ be identical
cannot
Common solvents listed from most dense to least dense.
chloroform, dichloromethane, water, diethyl ether, hexanes.
Listing compounds slowest to fastest Sn1 reaction rate.
chloromethane, 1-chloro-3-methylpentane, 2-chloro-3-methylpentane, 3-chloro-3-methylpentane
Four Major Methods of Purification
chromatography, distillation, recrystallization, extraction
What compounds are commonly used as oxidizing agents?
chromic acid and sodium dichromate
To dry the reaction product
combine the organic layers over anhydrous potassium carbonate
small fire contained completely in beaker
cover flame with watch glass or hard-back book
To handle the separatory funnel properly
cradle the inverted separatory funnel in the palm of the hand and hold the stopper between the fingers of the same hand
In dehydration of cyclohexanol, we converted ______ into _____ by an acid-catalyzed ____ reaction.
cyclohexanol, cyclohexene
Rf is ______ on polarity.
dependent
What components of the phase transfer catalysis experiment elute from the column?
dichloromethane, allyl naphtyl ether
The two liquid in an extractions must have ______ affinities for the material being isolated.
different
The two liquids in an extraction must have ________ densities. You want your desired material to wind up in only one of the two layers.
different
When taking a mixture melting point, A broad melting point or a melting point that is greatly different from that of the original compounds can be taken as proof that the compounds are _____.
different
_____ materials can have the same TLC values
different
Conformations
different geometries that a molecule can attain by bond rotations and bends are called conformations
How to calculate Rf value
distance traveled by the compound divided by the distance traveled by the solvent
When solvent front has reached the correct height, remove from the chamber and immediately ________ at the solvent front.
draw a line
One should spot the plate on the ____ side
dull
A theoretical plate is
each vaporization-condensation
After a ring flip an axial substituent in one chair form becomes an _______ substituent
equatorial
Substituents larger than hydrogen prefer to adopt ______ positions due largely to a smaller amount of steric strain.
equatorial
A recrstayllization solvent should not dissolve the compound while hot
false
A recrystallization solvent should chemically react with compound
false
A recrystallization solvent should dissolve compound while cold
false
For recrystallization, rapid cooling gives the best crystals.
false
Acetone is _____
flammable
Ethyl acetate is ____
flammable
Hexane is _____
flammable
anti conformation
global energy minimum (least amount of steric repulsion)
reflux means
heating a liquid to boiling and condensing the vapors back into the flask
If a student needs to heat things over 100 *C, a _______ should be utilized
heating mantle
Solvent with _____ dielectric constant increases the rate of reaction.
high
Nonpolar compounds will have _____ Rf values.
higher
fraction 3 should contain most of the ____ boiling component
higher
In extraction, ______ was first added to the separatory funnel before recovering Benzocaine or Benzoic acid
hydrochloric acid
Solubility in water increases when _______ increases.
hydrogen bonding
Highest to lowest Rf value
ibuprofen, aspirin, acetaminophen
When taking a mixture melting point, A sharp melting point in the same general range is a indication that the compounds are_______.
identical
How can a student know how much drying agent to use?
if drying agent swirls, student has added enough. if the drying agent stays clumped together, the student needs to add a little more drying agent to the sample.
Over time the amount of the most volatile component in the distillate ________.
increases
C=O stretch
indicates ketone
Acetaminophen is most polar because
it has two of these hydrogen bonding groups
Ibuprofen is least polar molecule because
it only has one polar carboxyl group
Alkenes
just above 3000 or at 1650
Secondary alcohols are oxidzed to _____
ketones
Highest Rf value is ____ polar
least
Components with a higher boiling point are _____ volatile
less
the polarity of a C-Cl bond is ___ than the polarity of a C-O or O-H bond
less
some compounds will elute from the column earlier than others, this is due to ______. This is how seperation is effected.
less interaction with the stationary phase
Each vaporization and condensation step enriches the _____ boiling liquid component in the vapor
lower
For an impure substance, the melting point is ____ than that of a pure sample.
lower
Fraction 1 when distilling should contain most of the ______ boiling component
lower
If the thermocouple is too high in the distillation apparatus... then the recorded boiling point will be ____ than expected because the bulb is not exposed to hot vapor.
lower
Polar compounds will have ______ Rf values.
lower
The eutectic mixture also melts at the ______ temperature observed for any mixture of the two compounds.
lowest
Prodcedural Step 3 of Oxidation of Secondary Alcohols
maintain the reaction temperature between 40 and 45*C on a steam bath
TLC Procedural step 2
make a pencil mark on the TLC plate 10 mm from the bottom
TLC Procedural step 6
mark the outline of the spots on the plate with a pencil. unless the spots are colored, some visualization method will be needed.
density is
mass/volume
______ solvent polarity results in more separation between spots
maximum
TLC Procedural step 7
measure the distance that the spot and solvent have moved
When dissolving the compound use a _____ amount of solvent
minimal
What is not important in an TLC experiment?
monitoring the temperature of the solvent in a chamber
Allylic or benzylic primary carbocations are _______ stable than alkyl carbocations.
more
Components with lower boiling points are ____ volatile.
more
The smaller the boiling point difference, the _____ theoretical plates required.
more
The _____ stable the carbocation, the _____ the reaction.
more, faster
The liquid in the filter flask is called the
mother liquor
The quaternary ammonium salt carries the _____ to the organic layer
naphthalate anion
In the phase transfer catalysis experiment, an SN2 reaction occures between _____ & ______ to form an ether.
napthalate anion, allyl bromide
For a pure substance, the melting temperature range is _____ than that of an impure sample
narrower
a nonpolar solvent will lead to polar solutes remaining _____
near original spot
The solvent front should _____ get within 1 to 2 mm from the top of the plate
not
The edges of a TLC plate should ________ the filter paper
not touch
The allyl bromide is in the _____ layer
organic
In the phase transfer catalysis experiment, the bottom layer is _____ and contains ______.
organic, dichloromethane, allyl bromide, allyl 2-naphtyl ether, benzyltributylammonium chloride
In the oxidation of secondary alcohols, the bottom layer was ___ and contained ____ and ___
organic, methylene chloride, cyclohexanone
Halogens, like Br are _____ agents
oxidizing
Hydrochlorous acid is an _____ agent.
oxidizing
fire confined to small portion of clothing
pat fire out
only use a ____ to mark the TLC plate
pencil
To recover a mixture in case of a stopcock leaks
place beaker below the separatory funnel
To control the rate of reaction
place the reaction flask in an ice water bath
The order of relative stability is
primary < secondary < tertiary
The Rf value is defined as
ratio between the distance the spot moved and the distance the solvent moved
To avoid making the reaction mix becoming an emulsion
reaction stirred at a moderate, not rapid, pace.
If an oil forms you should....
reheat the solution
TLC Procedural step 5
remove the TLC plate when solvent is near the top of the plate and mark the solvent front with a pencil before the TLC plate dries
Possible compounds for "who has my compound" lab?
resorcinol, acetanilide, mandelic acid, benzoic acid, benzamide, maleic acid, urea, benzoin, anthranilic acid, cholesterol, adipic acid, salicylic acid, benzanilide, p-bromoacetanilide, p-chloroacetanilide, p-toluic acid
Important features of chromatography are _______ and ______.
retention time (related to identity of the compound structure), peak areas of the peaks (related to amount of each substance in the mixture injected)
Hydrochlorous acid is
safer, less expensive, and enviromentally friendly.
The vapor of an azetrope has the _____ composition of the unboiled mixture.
same
Methanol is more polar than ethanol due to its
shorter carbon chain
The dectory in gas chromatography prints out a gas chromatogram as a plot of ______ vs _____.
signal intensity detected, time since injection
Azetropes can occur between substances that have ______ properties or _____ properties.
similar, different
What effect will result if the filtrate solution is cooled too rapidly?
small impure crystals will form
for recrystallization, material must be a _____
solid
To deprotonate alcohols to become good alkoxide nucleophiles
solid sodium hydroxide was added to 2-napthol
entire room is on fire
sound fire alarm and leave building
TLC Procedural step 4
stand the TLC plate upright in the chamber and replace the lid
The distance the solvent moves is measured from where the spot _____ to where the solvent front ____.
starts, ends
The distance the spot moves is measured from where the spot ____ to where the center ____.
starts, ends
The _____ phase is a very high-boiling liquid adsorbed onto fire brick.
stationary
The ______ phase is more polar than the _____ phase.
stationary, mobile
The twist boat conformation of a cycohexane has _____ strain and _____ strain, but is free of ____ strain.
steric, torsional, angle
O-H stretch
strong & broad, indicates alcohol
The dehydrating acid was a mixture of _____ in the dehydration of cyclohexanol
sulfuric acid & phosphoric acids
toxicity means
sum of adverse effects resulting from exposure to a material, normally by mouth, skin, or respiratory tract
Procedural Step 1 for SN1 Solvolysis Experiment
Add a few drops of bromothymol blue to a stirred solution of ethanol and water
How can a student determine which layer is which?
Add a little of distilled water to see which layer the water adds to.
Procedural Step 3 for SN1 Solvolysis Experiment
Add alkyl halide and start the timer.
Prodcedural Step 2 of Oxidation of Secondary Alcohols
Add bleach dropwise into the flask
Prodcedural Step 5 of Oxidation of Secondary Alcohols
Add drops of 6 M NaOH until solution is pH 6-8
To destroy the oxidizing agent
Add sodium bisulfite solution
How is neutralization of HOCl accomplished?
Add sodium bisulfite, NaHSO3.
Procedural Step 2 for SN1 Solvolysis Experiment
Add sodium hydroxide solution from a burette. Note the volume.
Procedural Step 2 of Phase Transfer Catalysis
Add sodium hydroxide to the reaction flask
Procedural Step 2 of Recrystallization
Add the minimum amount of hot water to just dissolve the solid
Procedural Step 2 of Solvent extraction
Add water to dissolve the brown emulsion between the layers
Procedural Step 5 of Solvent extraction
Add water to dissolve the white gel-like emulsion
Which of the given actions will increase the percent recovery of the acetanide solute?
After the first filtration, allow the solution to cool slowly, then place solution in an ice-water bath for 10 minutes
Procedural Step 7 of Recrystallization
Air dry the purified solid on the filter
Procedural Step 5 of Recrystallization
Allow the filtrate to cool slowly, then cool in an ice bath to force precipitation
To keep the time needed to complete the reaction under an hour
Allyl bromide was used in excess
A single, milky liquid develops, with no real sign of any layers, what is this?
An emulsion
Infared spectra are recorded using an ATR detector. What does this stand for?
Attenuated Total Reflectance
Procedural Step 6 for SN1 Solvolysis Experiment
Heat on a steam bath above 50 degrees celsius for 20 minutes.
Increasing polarity from left to right
Ibuprofen, Asprin, Acetaminophen
Who Has My Compound Procedural Step 2
Invert the tube and tap gently to move the solid to the bottom of the capillary
_____ compounds generally have higher solubilities in more ____ solvents.
Ionic, polar
Why is it good practice to perform a mixed melting point determination at two different ratios of an unknown to known material in the melting point capillary?
It is possible on particular combination of materials generates a eutectic
Prodcedural Step 1 of Oxidation of Secondary Alcohols
Mix cyclohexanol and acetic acid in an erlenmeyer flask
Stir bars and boiling chips should _____ be used together.
NEVER
Proper procedure for cleaning sulfuric acid spill?
Neutralize the spill with sodium bicarbonate
Who Has My Compound Procedural Step 4
Observe the material through the complete melting process to get a rough estimate of the melting range
Procedural Step 4 of Phase Transfer Catalysis
Periodically stop the stirring, allow the layers to settle, and spot the organic layer on a thin layer chromatography plate.
Distillation is a physical separation or chemical reaction?
Physical separation
Prodcedural Step 6 of Oxidation of Secondary Alcohols
Place reaction in separatory funnel, extract with dichloromethane.
Procedural Step 4 of Solvent extraction
Place the dichloromethane layer back in the separatory funnel and extract it with 3 M NaOH. Allow layers to settle.
Procedural Step 1 of Recrystallization
Place the impure substance and a boiling chip into an erlemeyer flask on a heating element.
Who Has My Compound Procedural Step 3
Place the tube with sample into the melting point apparatus, heat at 10 degrees per minute
Who Has My Compound Procedural Step 1
Press Open end of capillary tube into solid sample
The phase transfer catalyst used is
Quaternary ammonium salt (polar interacts w aqueous phase, 4 large alkyl chains allow it to be in organic phase)
To separate the nonpolar ether product from the polar byproducts
The contents of the reaction flask were passed through a column of silicia
Would the magnitude of steric strain increase or decrease if the dihedral angle was increased from 60* to 65*?
The magnitude of steric strain will decrease because the groups are moving further apart.
The two liquid in an extraction must be immiscible. This means _____.
the two liquids must form layers.
What is measured in this spectroscopic method?
the vibrational frequency of a bond
Would torsional strain increase or decrease when the dihedral angle of a gauche butane is increased from 60* to 65*?
Torsional strain increases
To test for presence of oxidizing agent
Touch a drop of the reaction mix onto a piece of KI-starch paper
If one is going to reextract the upper layer with another volume of liquid, the upper layer can be left in the seperatory funnel and fresh solvent added to the funnel.
True
The presence of impurities introduce entropy, which lowers the energy required to melt the material.
True
Unknown liquid that boils at a constant temperature is not necessarily pure and can potentially be classified as an azeotrope.
True
Who Has My Compound Procedural Step 5
Turn off and allow to cool by 15 degrees
Procedural Step 4 of Recrystallization
Wash the filter with hot solvent and transfer the filtrate to a clean flask
During TLC experiment, how is the dilute solution applied to the TLC plate?
a thin glass spotter or capillary tube
A eutectic is
a unique mixture of A and B that has a sharp melting point.
Which is most soluble in hot water? - salicylic acid -acetaminophen -2 napthol
acetaminophen
The compounding being purfied in in the recrstyalization lab was _____
acetanilide
Solvents listed from slowest to fastest Sn1 reaction
acetic acid, acetone, ethanol, methanol, formic acid, water
Highest frequency carbonyl stretch to lowest is
acetylcyclohexane, acetophenone, benzophenone
_____ react with sodium bicarbonate
acids
Which procedure should a student not do if they observe an oil forming as the solution cools?
add a small amount of ICE-COLD water to the solution with the oil
To precipitate the benzocaine
add base to the aqueous acidic layer mixture
To generate the oxidizing agent
add bleach dropwise into a flask contiang acetic acid
TLC Procedural step 1
add just enough developing solvent to cover the bottom 3 mm of the TLC chamber. cover w watch glass
To dissolve the emulsion due to benzocaine salt exceeding its solubilirt
add water to separatory funnel that contains an acidified three-component mixture in dichloromethane
To place a stir bar in, ___ the flask and ____ the stir bar in.
tip, slide
What is the purpose of the moist filter paper in the TLC chamber during the TLC experiment>
to ensure that the air in the chamber is saturated with solvent vapor
What is the purpose of an initial hot vacuum filtration in the recrystallization process?
to remove insoluble solid impurities
A recrystallization solvent should dissolve compound when hot.
true
A recrystallization solvent should either dissolve the impurities at all temperatures or not dissolve impurities at all
true
A recrystallization solvent should not chemically react with the compound
true
A recrystallization solvent should not dissolve compound when cold.
true
Desnity DOES NOT always increase as molar mass increases
true
Filter paper should be wetted before use in hot vacuum filtration
true
In gas chromotography, a carrier gas goes through the colum. Compounds interact differently with the stationary phase of the column.
true
It must be possible for you to isolate your product from the liquid into which it is extracted.
true
Methylene chloride is a probable human carcinogen.
true
The rate of heating affects the number of theoretical plates in the column
true
in permangage test, brown preciptate forms in presence of _______ bond.
unsaturated double
TLC Procedural step 3
use a capillary to deliver a 2 mm diameter spot onto the pencil mark
large portion of one's clothes is on fire
use safety shower or fire blanket
Procedural Step 6 of Recrystallization
vacuum filter the cold suspension
The stopcock cane be used to _____ excess pressure if either of the liquids is warm to the touch and has a low boiling point.
vent
The solvent in recrstyallization lab is _____
water
in gas chromatography, the injection port and dectored are heated to a temperature _____ abod the compound's boiling point
well above
When is recrystallization not a suitable method to purify an organic material?
when the organic material is a liquid instead of a solid
The reason that you should take mixture melting points of two sample mixtures with different ratios of the materials is that you need to ensure ________________________.
you have not made a eutectic mixture
In which of the following ways is the use of an infared spectrophotometer fitted with an ATR sample advantageous over a beam-through-sample spectrophotometer?
- Sample preparation and clean up of ATR is simple - ATR allows for the use very small samples.
why should the stopped be removed?
- allow the layers to seperatre more easily - allow layers to be drained through stopcock
How to recover benzocaine from aqueous acidic layer?
- take aqueous acidic layer and make it basic by adding 6 M sodium hydroxide (check for basic pH) - cool slowly - isolate crystals of benzocaine by vacuum filtlrate
What is the first step of using a separatoy funnel for extraction?
- to make sure the funnel stopcock is closed and then carefully pour the liquid to be extracted into the funnel
What should one do if an emulsion has formed?
-Add a small quantity of water, if that does not work add solvent.
Staggered conformation
-No overlap of atoms along the line of sight
In order to recover Benzoic acid from the aqueous basic layer
-acidify basic aqueous layer by slowly adding 6M hydrochloric acid - pH should be acidic (below 4!) - perform vacuum filtration.
You can increase the number of theoretical plates by
-packing column with glass beads/rings
Why must moisture be excluded from any sample injected into the GC?
-water contains dissolved salts than can clog the injector -water is very slow to elute from the columm
minimum Rf value
0
maximum Rf value
1
Spots should be __ to ___ mm in diameter
1, 2
The micro-scale distillation had _____ theoetical plates
1-2
a bp difference of 2 * C requires ____ theoretical plates
100
Anti conformation occurs at an angle of
180*
C=C alkene is which band length?
1800-1640 cm^-1
C=O aldeyhyde is which band length?
1800-1640 cm^-1
melting point range greater than ____ °C indicates that the compound is impure
2
Who Has My Compound Procedural Step 7
Heat at 2 degrees per minute through the expected range
Which is least soluble in hot water? - salicylic acid -acetaminophen -2 napthol
2 naphthol
Azetropes can form between mixtures of ___,____,____ compounds
2,3,4
Phase Transfer Catalysis experiment involved converting _____ & ____ into _____ .
2-naphthol and allyl bromide, allyl 2-naphtyl ether
when extracting benzoic acid from the dichloromethane us _____ M of sodium hydroxide
3
alcohols
3200-3600 cm^-1, broad OH
Alkynes
3300 cm^-1 or 2100-2260
What region of infared spectrum is most useful for distinguishing between isomers that contain the same functional group?
400 - 14000 cm^-1
O-H Alcohol stretch is in which band length
4000 - 3000 cm^-1
a bp difference of 35* C requires ______ theoretical plates
5
The TLC solvent front should be allowed to get _____ from the top of the plate
5 to 10 mm
How much impuritiy was in the inital mixture forr the extraction lab?
5%
Chair conformation contains ___ axial hydrogens that are _____ to the ring and _____ to the ring axis. It also contains ____ equatorial hydrogens that are in ____ of the ring around the ring equator.
6, perpendicular, parallel, 6, plane
Gauche interactions occur at angle of
60 *
the cycyclohexene & water boiling at ____
7 *C
cyclohexanol & water boils at _____
98 * C
What would provide the most conclusive evidence that two samples are the same compound?
A mixture melting point
Why is it important to allow the Mel-Temp to cool 15*C before placing the second capillary tube in, and to set the voltage generate 1-2*C temperature increase per minute?
A rapid temperature increase will give a melting point range that is too high.
When should students throw away their washes when using the separatory funnel?
AT THE VERY END WHEN THEY KNOW WHICH LAYER THEY NEED.
Why would the reaction fail to work if the reactants are switched to 2-bromonaphthalene and allyl alcohol while retaining the same phase transfer catalyst, solvent, and base?
Because the bromo group is a poor leaving group when attached to an aromatic ring
Carbonyls (like ketones)
C=O, 1670 cm^-1 - 1830 cm^-1.
Solvent that will most effectively dissolve NaCl of given choices: CHCl3, CH3OH, CH3CH2OH, CH2Cl2
CH3OH
bubbles forming in the solution during the sodium bicarbonate solubiltiy test are ____
CO2
Procedural Step 7 of Solvent extraction
Collect and dry the solids in both erlemeyer flasks by filtration
Procedural Step 3 of Phase Transfer Catalysis
Cover the reaction vial and stir
Prodcedural Step 8 of Oxidation of Secondary Alcohols
Decant from the potassium carbonate and collect by distillation
How could eugenol be seperated from a mixture of other non-acidic molecules?
Dissolve the mixture in dichloromethane, shake with sodium hydroxide, collect aqueous layer, and reacidify to force precipitation of the eugenol.
Procedural Step 1 of Solvent extraction of the three-component mixture composed of benzoic acid, benzocaine, and neutral organic molecule, all dissolved in dichloromethane.
Dissolve the solid three-component mixture in dichloromethane and place in a separatory funnel. Add 6 M HCl to the solution. Shake and allow to settle into layers.
Prodcedural Step 7 of Oxidation of Secondary Alcohols
Dry the dichloromethane layer over potassium carbonate
The acid catalyzed dehydration of a secondary alcohol proceeds through _____ mechanisms.
E1 and E2
To remove dissolved water from the reaction mixture
Enough calcium chloride to cover half the bottom of the flask was added
Why is ethanol not a suitable solvent for the solvent extraction of a benzoic acid and benzocaine from aqueous solution?
Ethanol is miscible w water
Procedural Step 7 of Phase Transfer Catalysis
Evaporate the dichlormethane solvent to dryness
The presence of impurities introduce entropy, which raises the energy required to melt the material.
False
A hot vaccumn filtration is used to
Filtering Insoluble Impurities
Procedural Step 1 for Phase Transfer Catalysis Experiment
Fit a conical vial with a stirring vane and add 2-naphthol, allyl bromide, and benzyltriammonium chloride in dichloromethane.
Procedural Step 3 of Recrystallization
Rapidly filter the hot solution through pre-warmed funnel
1-Chloro-1-phenylethane undergoes solovolysis in water to make 1-phenylethanol. What is true?
Rate of gin of acid is equal to rate of loss of alkyl halide. -The reaction follows first-order kinetics because there is one reactant in the rate-determining step.
Procedural Step 4 for SN1 Solvolysis Experiment
Record the time it takes for the solution to turn green
Procedural Step 5 of Phase Transfer Catalysis
Remove the bottom layer and dry over calcium chloride
Prodcedural Step 4 of Oxidation of Secondary Alcohols
Removed unused bleach with sodium bisulfite solution
Procedural Step 5 for SN1 Solvolysis Experiment
Repeat the process of adding aliqouts of measured base, recording the time taken for a color change.
Who Has My Compound Procedural Step 6
Replace the existing tube with a new sample
TLC is interpreted in terms of ____ values
Rf
Procedural Step 6 of Phase Transfer Catalysis
Run the reaction solution through a silica chromatography column
Procedural Step 6 of Solvent extraction
Separate and collect the aqueous layer in a flask, add acid.
Procedural Step 3 of Solvent extraction
Separate and collect the aqueous layer in a flask, and add base.
In "Who Has My Compound," the lab included a solubility test for the unknown compounds in what subtance?
Sodium bicarbonate
TLC run in 1:1 hexane:tetrahydrofuran, What change could be made to get the spots to move further up the plate?
Spot a new and plate run in a 1:4 hexane:tetrahydrofurane, it would allow spots to seperate more
Would steric strain increase or decrease in a gauche butane if the C-C-C bond angles increased to more than 109.5?
Steric strain will decease because groups are moving further apart.
When performing a bromine test on a compound, what indicates the presecne of an alkene?
The reddish color of the bromine will disappear.
Procedural Step 7 for SN1 Solvolysis Experiment
Titrate the contents of the flask against sodium hydroxide, record the volume.
Purpose of Cold Vaccum Filtration
To recover the pure product
which of the given statements best describes eutectic composition?
the composition of a mixture of two components that generates the lowest possible melting point
When mixing in a separatory funnel, the combined level of liquids should not exceed
the height of the widest part of the separatory funnel
How would the melting point range of a pure organic material be changed if there was a tiny shard of broken glass inside the melting point capillary?
the melting range would not be affected
Why should ink not be used to mark TLC plate?
the mobile phase can dissolve the ink and move it up the plate
Recrystallization is
the process of dissolving solid material into a suitable solvent or mixture of solvents, allowing the material to crystallize from this solution.
Density is defined as
the ratio of a substance's mass to its volume, measured in grams per milliliter, and equivalent to grams per cubic centimeter
