Ochem Lab Exam

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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


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