Ochem Lab Quizzes
In today's experiment (SN1 reaction), 2-butanol is synthesized from 2-bromobutane 2-butanol is synthesized from 2-bromobutene 2-bromobutane is synthesized from 2-butanol 2-bromobutene is synthesized from 2-butanol 2-bromobutyne is synthesized from 2-butanol
2-bromobutane is synthesized from 2-butanol
how many moles is 2.8 mL of the substrate in this week's reaction
27 mmoles
The total number of stereoisomers of Tartaric Acid are:
3
after one round of extraction from the separatory funnel, "solvent 1" has a concentration of 0.08 M and a concentration of 0.02 M in solvent 2. what is the partition coefficient?
4.0
The boiling point of dichloromethane is ___ degrees C
40
what concentration of phosphoric acid is used in the reaction? 100% 85% 80% 75%
85%
How many degrees of unsaturation are in cyclohexene? 0 3 1 2 4
2
In this experiment you will perform simple distillation. Which of the following compounds would be the primary distillate? Ammonium bromide Byproducts Butyl carbocation 2-Bromobutane 2-Butanol
2-Bromobutane
Which of the following best describes an azeotrope?
A mixture of volatile components that distills at a constant boiling point and with a constant composition
"When plane polarized light is passed through a single enantiomer of a chiral molecule the plane of polarization is rotated. When the opposite enantiomer of the same chiral compound is interacted with the plane polarized light, the angle of the rotation will be:"
Equal and opposite direction
"After running a GC experiment on an unknown mixture of components, you find two peaks integrating to 3.1 and 6.2. How many different compounds make up the mixture?"
at least two compounds
During the active distillation of a pure compound, the distillation head temperature will be _____ the temperature in the pot.
equal to
for a polar stationary phase, which solvent will elute the analyte more quickly
ethanol
which of the following is incorrect for the description of diethyl ether (often called ether)?
ether vapor is lighter than air
after oxidation with kMnO4 in presence of NaOH, two molecules of CO2 were formed. then the alkene was
ethylene
The reaction performed in this experiment is None are correct First order with respect to [HBr] Bimolecular Second order First order with respect to [ROH]
First order with respect to [ROH]
The vapor pressure of cyclohexene is____ the vapor pressure of water, at 70 degrees Celsius.
Greater than
What is the source of the bromide group in today's experiment for the preparation of 2-bromobutane from 2-butanol? Br2 that is produced in situ by reaction of sulfuric acids and ammonium bromide None Br2 is added from outside as a reactant HBr that is produced in situ by reaction of sulfuric acids and ammonium bromide HBr is added from outside as a reactant
HBr that is produced in situ by reaction of sulfuric acids and ammonium bromide
Which of the following interactions is the strongest?
Hydrogen bonding
imagine that you are immersed in your research project and you forgot to label two identical vials containing your starting material and product form an acid catalyzed dehydration reaction. Unfortunately, the materials have similar physical appearances. What methods could you use to properly label the two vials? I. Baeyer test II. Bromine test III. Fractional distillation IV. thin-layered chromatography analysis
I, II, and III
Which of the following is/are commonly used as a test for unsaturation? i. 2% KMnO4 in water ii. Bromine in dichloromethane iii. cyclohexane
I. and II.
What is the leaving group in SN1 reaction for the conversion of 2-butanol to 2-bromobutane? Sulfuric Acid Ammonium bromide Hydroxide Water Bromide
Water
Which solvent has the highest boiling point? Ethyl acetate Water Acetone Ethanol diethyl ether
Water
When we write the complete definition of Specific rotation, of a chemical compound, we should always specify two parameters outside the parentheses by convention. What are those parameters?
Wavelength of the light used & temperature
liquid liquid extraction is usually carried out using an apparatus called
separatory funnel
waste for this experiment should be disposed in _______________________.
solid waste container
select the appropriate order of mechanistic steps, that describe the dehydration of cyclohexanol, in this week's reaction
stepwise: protonation of alcohol, loss of water, and then deprotonation
the putative mechanism for bromine addition involves anti-addition of the bromine atoms. because of this observation, we refer to the following reaction as being _________
stereospecific
Lachrymatory compounds are defined as being _________.
tear inducing
lachrymatory compounds are defined as being
tear inducing
Why is it necessary to make sure Diastereomeric micture of the racemic 1-Phenylethanamine with resolving agent during the process of the Resolution?
"Diastereomers have different physical properties(like solubility, Boiling Point etc), that is why they are easy to separate from the mixture"
"To resolve the racemic mixture, which of the following will be added to the solution?" (-)-Tartaric acid a racemic mixture of tartaric acid (+)-1-phenylethanamine (+)-Tartaric acid (-)-1-Phenylethanamine
(+)-Tartaric acid
Which compound should form the most stable carbocation? CH3CH2CH2OH (CH3)3COH (CH3)2CHOH CH3CH2CH2CH2OH CH3CH2OH
(CH3)3COH
"In this experiment, which of the following chemical is isolated?
(s)-(-)-1-phenylethylamine
during the oxidative cleavage of a double bond, the oxidative state of Mn from the permanganate ion changes from ____ to ____
+7 to +4
what are the melting points of m-anisic and m-toluic acid, respectively?
106-108ºC and 108-110ºC
In an extraction procedure, it is advisable to:
- Save all layers until the experiment is complete
How do you calculate the relative abundance of each peak in your GC trace?
1/2WxH
what should be the initial rate of temperature rise in the mel-temp apparatus?
10-20ºC/min
what are the melting points of m-anisic acid m-toluic acid, respectively? choose the best answer
106-108 and 108-110
Under the reaction condition, hydrogen bromide is generated in the reaction mixture from its "synthetic equivalent." Which of the following statements is not correct? At room temperature, hydrogen bromide is a nonflammable gas A solution of ammonium bromide in aqueous phosphoric acid functions as the synthetic equivalent The concentration of free hydrogen bromide is quite low due to the unfavorable equilibrium A solution of ammonium bromide in aqueous sulfuric acid functions as the synthetic equivalent Hydrogen bromide is volatile
A solution of ammonium bromide in aqueous phosphoric acid functions as the synthetic equivalent
Hot filtration does not required a ________. fluted filter paper gravity filtration buchner funnel short stemmed funnel hot solution
Buchner Funnel
which of the following compounds will form a salt when added to a solution of sodium hydroxide?
CH3COOH
which one of the following anhydrous salts will be used as the drying agent for today's experiment?
CaCl2
Cyclohexanol has a higher boiling point than cyclohexene due to Intramolecular hydrogen bonding Intermolecular hydrogen bonding van der Waals forces ion-ion interactions
Intermolecular hydrogen bonding
what is the brown precipitate formed after oxidation with KMnO4
MnO2
"In order to make the resulting crystals soluble in dichloromethane, you will add them to a solution containing which of the following?"
NaOH
What is the relation between configuration and optical rotation? no relation R is always + D is always - R is always - S is always +
No relation
Enantiomers differ in their:
Optical Rotation
Which of the following stereoisomer will be formed with Br2 addition to E-cinnamic acid?
Picture from album Front carbon: up CO2H, bottom left Br, bottom right H Back carbon: up left H, up right Br, bottom Ph
What is the relative reactivity of alkyl bromides with ethanolic silver nitrate? None R3CBr>R2CHBr>CH3Br>RCH2Br R3CBr>R2CHBr>RCH2Br>CH3Br R2CHBr>R3CBr>RCH2Br>CH3Br R3CBr>RCH2Br>R2CHBr>CH3Br
R3CBr>R2CHBr>RCH2Br>CH3Br
Which of the following physical property would be expected to be different for enantiomeric 1-phenylethanamines? boiling point solubility in organic solvent chemical shift values of protons in 1H NMR J coupling between adjacent carbon atoms rotation of plane polarized light
Rotation of plane polarized light
The aim of this experiment is to learn the SN1 reaction. Which of the following statements is not correct? "N" stands for a nucleophilic reaction Carbocation intermediates are involved during the course of the reaction "1" stands for first-order kinetics The rate of the reaction depends upon concentration of a nucleophilic component "S" stands for a substitution reaction
The rate of the reaction depends upon concentration of a nucleophilic component
the distribution (or partition) coefficient is
The ratio of the concentrations of a solute in two solvents at a particular temperature
All of the following are true about a pair of enantiomers except?
They have different physical properties
The purpose of adding anhydrous sodium sulfate is:
To remove the traces amounts of water present in the organic solvent
Aliquat 336 is an oxidant a reagent used during the work up a phase-transfer catalyst the solvent in this reaction a reductant
a phase-transfer catalyst
Which of the following is TRUE about a simple distillation of a nonvolatile solute and a volatile solvent?
a. The temperature in the distillation head remains constant at the boiling point of the solvent B. The solvent must be heated to its boiling point to distill c. The solvent is collected in the receiver flask d. The solute remains in the distillation pot e. All are correct (Answer)
Aliquat 336 is a quaternary ammonium salt a phase-transfer catalyst lipophilic all are correct trioctylmethylammonium chloride
all are correct
which is NOT a method used to determine purity?
all are used to determine purity: - thin layer chromatography - melting point range - boiling point - gas chromatography
Optic rotation is dependent on which of the following variables? all variables pathlength solvent temperature concentration
all variables
a mixture of m-toluic acid and m-anisic acid should melt
below 106ºC
melting points capillaries should be disposed of in the _________________.
broken glassware container
how does acid accelerate's this week's reaction
by creating a good leaving group
melting points are measured by heating a small sample of solid contained in a narrow glass __________________.
capillary tube
What intermediate is formed when cyclohexanol is heated in the presence of phosphoric acid?
carbocation
In this experiment, phosphoric acid is best classified as a(n) ____________.
catalyst
Bromination occurs on alkene functional groups, but not on alkenes found within aromatic functional groups, such as the phenyl ring of cinnamic acid. Chemists would describe the difference in reactivity as an example of ___________________ regioselectivity enantioselectivity diastereoselectivity steroselectivity chemoselectivity
chemoselectivity
Classify the product of this reaction's alcohol dehydration
cycloalkene
if a substance is impure the melting point will ___________________.
decrease and broaden
In order to reduce the boiling point of a liquid you may
decrease the pressure
the conversion of cyclohexanol to cyclohexene is considered a _______________ reaction.
dehydration and elimination
what property of the components makes them to separate from each other in the extraction process?
differential solubility of the components in two solvents
what is the role of CaCl2
drying agent
In simple distillation the following equipments are used except thermometer condenser fractionating column heat source round bottom flask
fractionating column
After the Baeyer test, add the reaction mixture to the ___________ waste container.
heavy metal
In gas chromatography, what is used as the mobile phase?
helium
in this experiment two solvents should be
immiscible
why are low boiling solvents used in acid-base extraction experiment?
it is because the compounds that are dissolved the organic layer can be isolated easily
Why is anhydrous CaCl2 is added to the flask which contains the ether solution
it's used to make the ether dry
TLC plates should be submerged so that the spots are _____ the surface of the mobile phase
just above
acid-base extraction experiment is a type of
liquid-liquid extraction
During a simple distillation of two volatile components, the distillation head temperature will be ________ the temperature in the pot
lower than
In which solvent does the racemic 1-phenylethanamines is dissolved during the formation of Diastereomeric mixture in this experiment? diethyl ether dihydrogen oxide methanol propanol ethanol
methanol
Which of the following substrates will not undergo an ionic reaction with Br2? propene acetone methyl phenyl ketone propyne propane
propane
which of the following substrates will not undergo an ionic reaction with Br2
propane
For the equilibrium reaction: A + B -> <- C + D What action would shift the equilibrium towards products? remove D during the course of the reaction remove B during the course of the reaction add external B during the course of the reaction add external D during the course of the reaction
remove D during the course of the reaction
from the equilibrium reaction: A+B<-- C+D. --> what action would shift the equilibrium towards the product?
remove D during the course of the reaction
which of the following statements must not be true according to the procedures this week
the product is soluble in cold dichloromethane
How many stereoisomers are formed from the reaction of trans-cinnamic acid with Br2? three one six four two
two
tetrasubstituted olefins yield _____ when oxidized by KMnO4
two ketones
which of the following is incorrect?
two liquids are said to be miscible, if they are not completely soluble in each other
how will you remove the unreacted KMnO4 from the reaction mixture?
using solid NaHSO3
the bromination of a double bond will result in a _____________
vicinal dibromide
after oxidation with kMnO4 in presence of NaOH, two molecules of carboxylic acid were formed. then the alkene was
vicinal disubstituted alkene
you will recrystallize the product from
water
