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102 Cards in this Set

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Jones Reagent Test
- corrosive

(+) Test indicates: 1 or 2 alcohols, amines, aldehydes, and phenols

False (-) : 3 alcohol

Solution turns from orange to blue-green
Bromine Test
- Toxic

(+) test indicates pi bonds, alkenes, aldehydes and phenols

Solution goes from brown to clear

False (+) : Dilution

False (-) : Too much reagent
2,4-DNP Test
- Corrosive

(+) test indicates aldehydes and ketones

Solution will contain precipitate when reacted with.

False (+) - Acetone washed glass

False (-) - Aromatic/hindered ketones
FeCL3 Test
(+) test indicates phenol.

The solution goes from yellow to some other color.

False (-) - Sterically hindered phenols
Ignition Test
(+) test indicates aromatic ring (ie benzene)

Sooty/smoky flame will indicate a positive test.

False (+) - Alkyl Halides

False (-) - Aromatics with many oxygens
Briefly explain how one can monitor the progress of a reaction by TLC.
The reactants, reactant mixture and product are placed on the TLC sheet.

After some time has passed, the dots will have moved and aligned.

The reaction is complete when the reaction mixture has only one dot and is aligned with the product.
What solvent will be used in the Diels-Alder reaction experiment, and what safety hazard does it present?
Toluene - it is very flammable
Why do cyclic dienes typically undergo Diels-Alder reactions more quickly?
They are permentally fixed in a cis configuration.
How will the product from today's experiment be isolated?
By filtration
Why is it not a good idea to clamp both the round-bottom flask and the condenser in the Diels-Alder experiment?
It will allow air to leak into the funnel.
Briefly explain what is meant by "heating at reflux"
Boiling a liquid and attaching a means to recollect the evaporate so that it is constantly vaporizing and boiling.
Why is using a cracked filter flask more dangerous than using a cracked Erlenmeyer flask?
The fliter flask is under extreme pressure due to the vaccuum.
Why is it necessary to remove the stopper from the seperatory funnel before draining it?
The stopper inhibits air flow and will not allow the stopcock to release the liquid.
Briefly explain why water was sufficient to pull the copper chloride away from the benzil, but 1M NaOH was required to seperate the p-ter-butylphenol from the benzil
Water is a great way to pull ionic bonds apart due to its polarity, but NaOH is more basic than water and pulled the acidic H+ from the alcohol group.
Why do cyclic dienes act faster than trans dienes?
Cyclic are always held in cis, making them more reactive.
What is the purpose of the watercool condenser
Acts as an aircoil
About how long did the Antrocene/maleic anhydrous heat at reflux?
About one hour.
Extraction of benzoic acid from mixed solution of benzophenone and benzoic acid
What is happening in this reaction?
Based on your data, which compound (napthalene, BHT or sodium benzoiate) is the most polar?

Which is the least polar?
Sodium Benzoate is the most polar because it fully dissolved in water, a polar sovlent. Also it has a slight solutibity in Diethyl ether, which has some polarity.

Napthalene is the least polar. It was not soluble in H2O, but it was soluble in Petroleum Ether and Diethyl Ether.
Based on the structures of the compounds, which compound (napthalene, BHT or sodium benzoate) is the most polar?

Which is the least polar?
Sodium Bensoate is the most polar because of the depronated carboxylic acids and the Na+ ions.

napthalene is the least polar because it has no Oxygens or Nitrogens, or any type of dipole. It is strictly a hydrocarbon cyclic.
London Dispersion

Dipole-Dipole
List all of the intermolecular forces present in pure solutions of each compound.
London Dispersion
List all of the intermolecular forces present in pure solutions of each compound.
London Dispersion

Dipole - Dipole

Hydrogen Bonding
List all of the intermolecular forces present in pure solutions of each compound.
Which compound (dimethyl ether, propane or ethanol) would have the highest boiling point?

The lowest?
Ethanol

Propane
Which compound (dimethyl ether, propane or ethanol) would be the most soluble in water?

The least?
Ethanol

Propane
What is one good way (in terms of technique) to try to dissolve a solid in a small amount of solvent in a test tube?
Put a cork stopper on the test tube and shake it up
Predict the best solvent:

Napthalene (nonpolar) should be most soluble in
Petroleum Ether
Predict the best solvent:

BHT (polar aprotic) should be most soluble in..
Diethyl ether
Predict the best solvent:

Sodium benzoate should be most soluble in...
Water
If a mixture of ether and water is placed in a seperatory funnel, which layer would be on the bottom?
Water
Extraction is a seperation technique. On the basis of what physical property are seperations achieved?

(In other words, differences in what property are used to separate mixtures of compounds when doing an extraction?)
Solubility.
In today's experiment, a mixture contianing the three compounds, benzyl, p-tert-butylphenol and copper (II) chloride, will be added to a mixture of ether and water.

Which layer (water) will each compound end up in?
Cu (II) Chloride
In today's experiment, a mixture containing the three compounds, benzyl, p-tert-butylphenol and copper (II) chloride, will be added to a mixture of ether and water.

Which layer (ether) will each compound end up in?
benzyl
p-tert-buytlphenol
What is the equation for P.C?

(water partition coefficient)
P.C = {(Amt of compound in better solvent)/(volume of better solvent)}
_________________________
{(Total amt)-(amt in better solvent)/(volume of worse solvent)}
After the first extraction (of water and ether) the compounds remaining in the ether layer are extracted with 1 M naOH (a strong base).

One of the structures changes and this compound is 'dragged' into the new water layer.

Draw the new structure and explain why this compound is suddenly soluble in water.
This structure had it's H+ stripped away, forming an ionic bond with Na+ and making it soluble in water because of this ionic bond.
What is the melting point of Octane according to ChemFinder?
125.5 °C
What is the melting point of isooctane according to ChemFinder?
99.0 °C
Why does isooctane have a lower boiling point than octane?
As surface area increases, van der waals forces increases, thus raising the boiling point.
When bubbles first start coming out of the boiling point microcapillary, why is the temperature of the oil not taken to be the boiling point of the liquid?

(In other words, why do you have to wait until the bubbles become a steady stream, and then stop when the oil is cooled?
The bubbles began to form because of the huge increase in kinetic energy, but this does not determine exactly what the boiling point is.

The pressure is higher outside the tube than inside, and once the pressure equalizes and the temperature decreases, the boiling point can be determined.
Would you expect the boiling point of 1-heptanol to be higher or lower than that of octane?
1-heptanol will have a higher boiling point because of the alcohol group that contains hydrogen bonds, as well as dipole-dipole interactions
What is recrystallization
Technique which seperates based on solubility.

As temperature increases, so does solubility.
T/F - Slowly cooling will yield more pure product.
TRUE -
What was dimethyl maleate acting as in the alkene isomerization lab?

MP 91-99 degrees C
Starting material
What was dimethyl fumerate acting as in the alkene isomerization lab?

MP 101-102 deg C
Product
What was morpholine acting as in the alkene isomerization lab?
Nucleophile
What was ZnCl2 acting as in the alkene isomerization lab?
Lewis acid catalyst
What was methanol acting as in the alkene isomerization lab?
Solvent
What was diethyl ether acting as in the alkene isomerization lab?
Used in extractant
Stationary Phase is also known as what?
Absorbant Phase

Used Silica Gel (very polar) for chromatography.
Mobile Phase is also known as what?
The solvent.

In the chromatography lab, it was

Ethyl acetate .
Rf equation
Distance spot traveled
----------------------
Distance solvent traveled
Solubility
dissolving a substance into a liquid
Solvent
The liquid that does the dissolving
Solute
The substance being dissolved
Which intermolecular force is the strongest?

- Ionic interactions
- Hydrogen bonds
- Dipole - dipole interactions
- London dispersion
They are ranked according to their strength relative to london dispersion
Distillation seperates based on....
differences in boiling pointl.
Simple distillation involves...
An open tube that vaporizes the solution only once.
Fractional distillation involves
more surface area, which makes the solution vaporize and condense several times.
Normal phase
Silica gel -> very polar

seperates polar compounds
Reverse phase
Composed of (CH3)18

Very nonpolar

Located inside of the GC tube.

Seperates Nonpolar compounds
As impurities increase...
melting point decreases
What color is benzil?

MP?
yellow

95 deg C
What color is p-tert-butylphenol?

MP?
White

99.3 deg C
What is atmospheric pressure
The temperature at which a vapor pressure is above a liquid
As atm decreases....
BP decreases too
Temperature is a measure of ______ in particles.
Kinetic energy
In Experiment 4: TLC what is the stationary phase on the TLC plate?
The silica gel plate
In Experiment 4: how will we visualize spots on the TLC plate
Using UV light
What will be the result of the following errors in TLC technique?

Too much sample is applied
Larger spots than normal will appear, will not be able to calculate Rf
What will be the result of the following errors in TLC technique?

Solvent of too high polarity
The spots will be too close to the top.
What will be the result of the following errors in TLC technique?

Solvent in developing jar too deep.
The samples will mix together and skew results
What will be the result of the following errors in TLC technique?

Forgetting to remove TLC plate when solvent reaches top of TLC plate.
The Rf value cannot be determined
For Experiment 4: TLC, would your Rf values have been higher or lower if you had used a more polar solvent than ethyl acetate as the developing solvent?
The Rf values would have been lower if a more polar solvent was used because it would have moved the solutions closer to one another, thus lower Rf
For Experiment 6, Alkene Isomerization

Could a catalytic amount (less than one equivalent) of morphone be used?
Yes it could because the end product of the reaction is dimethyl fumerate and morpholine...

This allows it to catalyze other dimethyl maleate molecules.
How is the product from Experiment 6: Alkene Isomerization going to be seperated from the reaction mixture?
It's going to be put into a seperatory funnel that contains water and ether.
What physical property will be used to distinguish dimethyl fumerate from dimethyl maleate?
The melting point will increase.
RWhat effect is recrystallization expected to have on the melting point of your product?
The melting point should increase because crystallization favors creation of the sought after molecule and eliminates impurities...which lower the melting point.
Why does the addition of the 10% H2SO4 result in the formation of a precipitate?
It pulls off the Na+ ion and adds an H+. This changes the composition of the solution and forms precipitate because it's a neutral compound.
Recrystallizatino seperates compounds based on what physical characteristic?
Solubility
When doing a recrystallization, what is the purpose of cooling the crystallizing solution?
To "crash out" product
When dissolving the crude sample in hot solvent, why is it important to not use too much solvent?
The solvent may deprotonate the molecule that we are trying to isolate.
After dissolving the crude sample in hot solvent, why is it better to let the solution cool slowly rather than quickly?
This yields a purer product, quickly cooling will lead to impurities.
When "washing" the purified product (which has been collected in the filter) why should cold water be used instead of warm water?
The cold water will not dissolve the product, leaving us with a full collection of the product.
Which compound (n-octane or isooctante) had the shorter retention time?
Isooctane had the shoerter retention time beasue it was less nonpoalr than n-octane, which allowed it to move quicker through the Gas Chromotagraphy chamber.
What is a way to determine if isomerization was complete?
Detemine how close the experimental melting point is from the theorhetical melting point.
Why is fractiona distillation more effective than simple sitillation for seperating liquids?
Fractional requires that the liquids condensce multiple times, ensuring thatt the liquid is highly seperated
Distillation seperates compounds based on what physical property
Boiling point
What is one advantage of fractional distillation relative to simple?
It ensures that the liquid is more seperated than simple.
What is one disadvantage of fractional distillation relative to simple?
It takes much longer.
What will be the mobile phase (gas carrier) in the gas chromatography experiment?
SiCH2(CH3)18
The gas chromatograph we will use today has a nonpolar column.

Which compound will flow through the column at a faster rate?
Isooctane
What information is gained from measuring the relative areas of peaks in a gas chromatogram?
The % composition
What does the number of peaks in a gas chromatogram tell you about the composition of the sample?
The number of peaks equals the number of compounds in the sample.
Explain why impurities lower the melting point.
impurities disrupt the bonds of the substance we're testing.
During this experiment you will be monitoring the temperature of the silicone oil bath.

When will the temperature of this bath equal the boiling point of your unknown?
When the bubbles stop coming out of the microtube.
If a storm moves in and the atmospheric pressure drops, will the observed boiling points of the unknowns increse, decrease or stay the same?
The boiling points will decrease.
Dimethyl maleate

Starting material
What is this molecule's name?

What is it's purpose?
Dimethyl fumerate

Product
What is this molecule's name?

What is it's purpose?
Morpholine

Nucleophile
What is this molecule's name?

What is it's purpose?
ZnCl2

Lewis Acid
What is this molecule's name?

What is it's purpose?
Methanol

Reaction Solvent
What is this molecule's name?

What is it's purpose?
Diethyl ether

Used in extractant
What is this molecule's name?

What is it's purpose?