MCAT ORGANIC Chem Flashcards
Does the term allotrope refer to elements, compounds, or both?
only Elements
Are liquid water and water vapor 2 allotropes of H2O?
No.
Allotropes refer to different forms of an element IN THE SAME PHASE
What kind of hybridization holds the carbon atoms together in graphite?
sp2
(p 428, Barrons)
What does the term isomerism mean in chemistry?
Ability of atoms to arrange themselves in more than 1 way to give different compounds that have the same molecular formula (Nassau chem text by brady & senese)
atoms → different combinations → different compounds → same molecular formula
What is the name/term for compounds with the same molecular formula, but with atoms connected in a different order, and thus have different properties?
constitutional isomers
What’s another name for a constitutional isomer?
Structural isomer
What’s the other variety of isomer, besides structural isomers?
Stereoisomers
What is a stereoisomer?
molecules that have the same molecular formula, and have the same connections between the atoms, but have a DIFFERENT SPATIAL ORIENTATION
What does it mean to have the prefix n- in a molecule’s name?
n- stands for normal. This means that the molecule’s spine/longest carbon chain is a straight chain
What does trans- mean?
The groups attached to the double bonded carbons are on opposite sides.
Which isomer gives a straighter-looking molecule? Cis- or trans-?
Trans- isomers
True/False:
Cis- and trans- isomers have different chemical and physical properties
tru
Are your hands superimposable?
no
What is chirality?
“Handedness”. ‘
If one object is the mirror image of another object, AND if they are NOT superimposable, then these 2 objects are chiral.
What makes something organic?
A compound is organic if its molecules contain carbon.
Name 7 types/classes/groups of carbon-containing molecules that are NOT considered to be “organic.”
pure carbon and its allotropes,
CO2,
CO,
carbonates,
carbides,
cyanides,
thiocyanates, etc.
generally, organic compounds are held together by _____ bonds
covalent
CnH2n-2 is the general formula for which class of hydrocarbons?
alkynes
What is the general algebraic formula for alkanes?
CnH2n+2
What is the general formula for alkenes?
CnH2n
what is the symbol for acidity constant?
Ka
what’s another name/term for acidity constant?
Acid dissociation constant
The (stronger/weaker) the acid, the (higher/lower) the Ka.
stronger
higher
What is the relationship between Ka and pKa? (Hint: give the equation)
pKa =
- log Ka
A (stronger/weaker) acid has a (higher/lower) pKa.
Sronger;
lower
A strong acid yields a (strong/weak) conjugate base.
(p 46, McMurry)
weak
In electrostatic potential maps of molecules, what color is the more positively-charged region(s) of the molecule?
blue
_______ have a carbon bonded to a halogen
haloalkanes
What’s the other term for haloalkanes?
Alkyl halides
_____ have 2 carbon atoms bonded to the same oxygen
ethers
______ have a C bonded to an N, and that same C is not double-bonded to an O
amines
_____ have a C bonded to an –SH group
thiols
______ have 2 Carbon atoms bonded to the same sulfur
sulfides
T or F:
in functional groups, the bonds are polar
tru
in functional groups, the C has a partial ____ charge
positive
what is the suffix for an alcohol?
-ol
what is the suffix for an ether?
Ether. The word ether, by itself.
what is the suffix for an amine?
-amine
what is the suffix for a nitrile?
-nitrile
what is the suffix for a nitro?
there is none.
_______ a C that is both double-bonded to an O and also bonded to an N
amide
what is the suffix for an aldehyde?
-al
what is the suffix for a ketone?
-one
what’s another name for “straight-chain” alkanes? I.e., straight-chain alkanes are also known as _________ alkanes
“Normal” alkanes
when talking about alkyl groups, a primary carbon is bonded to ______ other carbon(s)
1
if an alcohol’s –OH functional group is attached to a carbon–that is itself attached to one other carbon–then that alcohol is called a [primary/secondary/tertiary/quaternary] alcohol
primary
generally, the symbol/letter R stands for
the rest of the molecule
the old-school, non-IUPAC name for alkanes was ______ ?
paraffins
alkanes are chemically (reactive/inert) to most laboratory reagents
inert
(p 86)
with alkanes, boiling point and melting point show (regular / irregular) increases with increasing molecular weight
regular
(p 87)
what causes the proportional, or direct or “regular”, increase in both the boiling point and melting point of alkanes?
London dispersion forces amongst the molecules, the intensity of which force increases with increasing molecular size of the alkanes
What effect does branching have on alkanes that have the same # of C atoms?
The more branching there is, the lower the boiling point
(mcmurry p 88)
Why is there an inverse relationship between the level of branching and the boiling point of alkanes?
Branched alkanes have smaller surface area, and thus smaller London dispersion forces
What’s the word used to describe hydrocarbons that are NOT aromatic?
aliphatic
T or F:
aliphatic compounds do not contain rings.
False.
“Aliphatic” refers to hydrocarbons that are not aromatic. But not all ring-compounds are aromatic.
in organic chem, what does the word aryl mean?
Refers to any functional group or substituent that has a simple aromatic ring
(wikipedia)
Given two isomers: if the isomers have different connections between the atoms, they are called “____________ isomers”
constitutional or structural isomers
What are enantiomers?
molecules that are Mirror-images of each other, but are not superimposable
What is meant by “conformation”?
the 3-dimensional shape of a molecule at any given instant
What is a chirality center?
An atom that is bonded to 4 different groups/substituents
What are conformation isomers? Describe/define it.
molecules that have the same molecular formula, and are just different arrangements of atoms that result from rotation around a single bond
What is torsional strain?
Strain in a molecule caused by electron repulsion between two segments (namely the H’s on opposite ends of the molecule) of the molecule that eclipse each other when the molecule is viewed thru the length of its spine
When talking about a molecule with a single bond, the lowest-energy, most stable conformation is the one in which all the H’s are [as far away from one another / as close to each other] as possible.
As far away from one another
The conformation of an ethane, at which all the hydrogens are as far away from each other as possible is called ___________
[choices are below as a hint]
hint: it’s either staggered or eclipsed
staggered
If torsional strain of an ethane molecule can be measured, what is its amount?
12 kJ/mol
How much is 12 kJ/mol in kcal/mol?
3kcal/mol
T or F:
conformational isomerism is a form of stereoisomerism in which the isomers can be interconverted by rotations about pi bonds
False.
Conformational isomers differ b/c of rotations around single, i.e. sigma, bonds
The anti conformation is the [lowest/highest] energy conformation of a butane
lowest
What is steric strain?
the repulsive interaction that occurs when atoms are forced closer together than their atomic radii allow
(mcmurry 107)
why are a lot of cycloalkanes not shaped like “flat” rings where all the C’s are all on the same plane?
The “puckered,” or irregular shape, of the cycloalkane gives it zero angle strain and zero torsional strain
With which alicyclic compound is the chair conformation seen?
Cyclohexane
Due to the chair conformation, there are 2 kinds of positions for substituents on the ring: _____ positions and _______ positions.
axial positions, and
equatorial positions
The substituents of cyclohexane that are in the ______ position are perpendicular to the ring (i.e., parallel to the ring axis)
axial
What is a conformer?
Another name for a conformational isomer
What’s another name for two or more conformational isomers that differ only b/c of a rotation around just 1 single bond?
rotamer
At any given instant, about ____ % of ethane molecules have a staggered conformation and only about ______ % are close to the eclipsed conformation
(mcmurry 104)
99
1
Another name for a chiral center or chirality center is __________
(Hint: 2 words)
stereogenic center
(berk review website)
Name the specific molecule/compound with which the term “chair conformation” is associated. I.e., what’s the molecule that comes to mind when you hear “chair conformation”?
cyclohexane
Besides the chair conformation, what other conformation(s) are possible with cyclohexanes? Name them.
Boat conformation
In a chair cyclohexane, what are the names of the two positions/orientations that the H atoms can have?
Axial and
equatorial
How many of the H atoms in a simple cyclohexane are in the axial position?
3
With monosubstituted cyclohexanes, a substituent is almost always more stable in an [equatorial/axial] position
equatorial
When you have a mixture of two isomers, which equation will allow you to calculate the percentage of each isomer in that mixture?
∆E = - RT ln K ← NOTE:
this eqn can be used if the mixture is at equilibrium
∆E = - RT ln K
What does R stand for in the equation given above?
Gas constant
What is the actual numerical value of R (don’t forget the units)?
8.315 J/(K∙mol)
Why is there a difference between the potential energy of a cyclohexane with an axial methyl group and the potential energy of a cyclohexane with an equatorial methyl group?
The energy difference is caused by steric strain between the methyl group and the other hydrogens
(p 120)
Why are 1,3-diaxial interactions so important? I.e., what are they responsible for?
This interactions results in the steric strain that is responsible for the energy difference between axial and equatorial conformers of a cyclohexane.
(mcmurry 120)
Which specific parts of a cyclohexane are involved in a 1,3-diaxial interaction?
The axial methyl group of a C1, and the H molecules of a C3 and C5
When talking about a trans-disubstituted cyclohexane, the two substituents are: (see choices below):
(a) both axial
(b) both equatorial
(c) one axial and the other equatorial
(a) or (b)
Which is the more stable conformation: boat or chair?
Chair
What does the word “polycyclic” mean?
Refers to compounds that contain two or more rings that are bonded together
What’s the difference between “polycyclic” and “heterocyclic”?
Heterocyclic refers to compounds having, as ring members, atoms of *at least two different elements *
(http://goldbook.iupac.org/H02798.html)
What’s the name of the reaction in which a single reactant undergoes a reorganization of bonds and atoms to yield an isomeric product?
Rearrangement rxn
What’s the name of a reaction in which 2 reactants add together to form a single new product with no atoms “left over”?
addition rxns
What’s the name of a rxn in which a single reactant splits into 2 products?
Elimination rxn
What’s the name of a rxn in which 2 reactants exchange parts to give 2 new products?
Substitution rxn
An overall description of a how a rxn occurs, is called a/an _________.
rxn mechanism
When a covalent bond breaks symmetrically so that 1 electron remains with each product fragment, the bond cleavage is called [homolytic/heterolytic].
Homolytic
If a covalent bond forms when both bonding electrons are donated by just 1 of the reactants, this type of bond making is called [homogenic/heterogenic] bond making.
Heterogenic
Radical rxns involve [symmetrical/asymmetrical] bond breaking and bond making
symmetrical
The opposite of ‘radical rxn’ is a ‘_____ rxn’
polar
[Larger/smaller] atoms are more polarizable.
Larger
Why are larger atoms more polarizable?
b/c their electrons are more loosely held than smaller atoms
The electron-poor reactant is called an/a (Hint below)
Hint: ____phile
Electrophile
True/false:
an electrophile may be either neutral or negatively charged
False.
Correct answer is, that an electrophile can be
either neutral or positively charged.
Lewis bases are [nucleophiles/electrophiles].
Lewis bases are electron donors and behave as nucleophiles.
another name for a carbon cation is _______.
carbocation
True/false:
Carbocations can accept electron pairs
tru
The word endergonic is associated with the [Δ** H / Δ G / Δ S]** of a rxns.
Δ G
The fancy term for Δ G is ‘_________ change’
Gibbs free-energy change
The fancy term for Δ H is ‘______ change’
enthalpy change
What is the symbol for ‘bond dissociation energy’?
D
Define bond dissociation energy
amount of energy required to break a given bond to produce 2 radical fragments when the molecule is in the gas phase at 25 degrees Celsius
[Cis/trans] alkenes are more stable
trans
Why are trans alkenes more stable?
b/c cis alkenes have steric strain between the 2 substituents that are on the same side of the double bond
True or False:
the more substituted the alkene, the more stable it is.
true
In Orgo, when you hear the word “attack” being used, which specific atom/molecule/particle is the “attacker”?
Electrons
What is Markovnikov’s rule?
(Hint: not the one referring to carbocations)
In the addition of a given molecule ‘H-X’ to an alkene, the H atom bonds to the double-bonded carbon that has FEWER alkyl substituents connected to it.
The X attaches to the double bonded carbon that has MORE alkyl substituents.
What’s Markovnikov’s rule when restated to include cations?
In the addition of H-X to an alkene, the more substituted carbocation is formed as the intermediate rather than the less highly substituted one.
True or false:
the more substituted a carbocation is, the less stable it is.
False.
More highly substituted carbocations are more stable than less highly substituted ones.
What’s the name of the stabilizing interaction between a vacant p orbital and a properly oriented neighboring C-H sigma orbital (mcmurry p. 191)?
Hyperconjugation
[is this really important for the MCAT??]
What is an alkyl group?
An alkane that is missing one hydrogen
What is the Hammond postulate?
Basically it states that we can get a picture of what given transition state looks like, by looking at the structure of the nearest stable species.
Thus exergonic rxns have transition states that resemble reactant;
endergonic rxns have transition states that resemble product.
When an s and a p orbital combine to form a hybrid orbital, what is the total # of orbital(s) formed?
2
What is the mathematical expression that tells u the number of hybrid orbitals on a given atom with a hybridization of ‘spx’?
1 + x
1 + x is the eqn that tells u the number of hybrid orbitals on a given atom with a hybridization of ‘spx’.
What are all the potential numerical values of X in the above expression?
1, 2, or 3
What expression tells you the percentage of the “s character” for any given orbital of spx?
1 / (1+x)
What percentage of an sp2 orbital has the p character?
67%
[use the formula x/1+x]
If a given atom in a molecule has a sum of 2 attached atoms and lone electron pairs, what is its hybridization?
sp
If a given atom in a molecule has a sum of 4 attached atoms and lone electron pairs, what is its hybridization?
sp3
What molecular geometry does an sp hybridization have?
Linear
What is the bond angle for an sp2 hybridization?
120
What is the bond angle for an sp3 hybridization?
109.5 degrees
T or F:
a saturated molecule contains pi bonds
false
What expression shows how many H atoms are present in a saturated compound that has n carbon atoms?
2n + 2
A _____-bond is formed by the parallel, side-to-side alignment of 2 unhybridized p orbitals on adjacent atoms.
π
What is bond dissociation energy?
The energy required to break a bond homolytically
When a bond is broken and both electrons go to just one of the resulting fragments, this kind of bond-breaking or bond-cleavage is called _______ (adjective)
heterolytic
Which type of bond cleavage results in the formation of two radicals?
Homolytic
When comparing the same type of bonds, the greater the s character in the bonding orbitals, the [longer/shorter] the bond
shorter
(p 452, TPRH bio)
Which bond would you expect to be shorter: an sp-s bond, or an sp3-s bond?
sp-s bond is shorter
Another name for a chiral center or stereogenic center is _______
stereocenter
What exactly is a chiral center?
An atom that has 4 different groups bonded to it.
In Orgo, a chiral center is usually which element?
carbon
What are enantiomers?
Isomers that are mirror images of each other AND are chiral.
What is the name for stereoisomers that are not mirror images?
(I.e., the overall name for the entire category, not just a specific subtype or variety)
diastereomer
T or F:
cis-trans isomers are a type of enantiomer
False.
Cis-trans isomers fall under the category of Diastereomers
Do enantiomeric pairs have differences in melting point?
no
Do enantiomeric pairs have differences in boiling point?
no
Do enantiomeric pairs have differences in dipole moment?
No (p 462, TPRH bio)
Do enantiomers have differences in their optical activity?
yes
What mathematical expression tells us how many stereoisomers a molecule can possibly have if it has n chiral centers?
2n
Can a molecule with n chiral centers have more than 2n stereoisomers?
no
Can a molecule with n chiral centers have less than 2n stereoisomers?
yes
What is a meso compound?
Molecule that has at least 1 chirality center, but has a plane of symmetry and thus is achiral
What are epimers?
Diastereomers that differ in their absolute configuration at ONLY ONE chiral center
For naming alkenes, the cis-trans naming convention only works with ____-substituted alkenes. (possible answer choices below)
Choices: mono-, di-, tri-, tetra-
di
What’s the name of the naming system developed for alkenes that are trisubstituted and tetrasubstituted?
E,Z system
What is ‘absolute configuration’?
the exact 3-dimensional structure of a chiral molecule
What set of rules are used to determine a molecule’s absolute configuration?
the Cahn-Ingold-Prelog rules
Epimers that form as a result of ring closure are known as ______
anomers
What specific type of organic molecules will you see the term ‘anomer’ associated with?
Sugars (saccharides)
Glucose in its ring form is called ___
glucopyranose
What are geometric isomers?
Diastereomers that differ in the orientation of substituents around a ring or a double bond
Name 2 types of geometric isomers commonly encountered in Orgo.
Cis-trans isomers; and
E,Z isomers
Describe the relationship between a molecule’s optical activity and its absolute configuration.
There is no correlation between a molecule being dextrorotary/levorotary and it being R or S
Hydrocarbons are generally nonpolar, yet can attract/repel each other to some extent.
Which force allows for these interactions among otherwise nonpolar molecules?
van der Waals forces, specifically London dispersion forces.
Does branching have any effect on boiling point and melting point for hydrocarbons?
yes
Branching [raises/lowers] the melting point of a hydrocarbon.
lowers
Branching [raises/lowers] the boiling point of a hydrocarbon.
Lowers
Increasing molecular weight [increases/decreases] MP of hydrocarbons.
increases
Increasing molecular weight [increases/decreases] BP of hydrocarbons.
increases
In organic chem, which structures/atoms/functional groups can function as hydrogen acceptors for a hydrogen-bond?
A lone pair of electrons on a nitrogen, an oxygen, or fluorine can accept an H an make a hydrogen bond
Can the oxygen of a hydroxyl group function as an H-acceptor for a hydrogen bond?
YES
In organic chem, which structures/atoms/functional groups can function as hydrogen donors for a hydrogen-bond?
An H that is attached to an N, an O, or an F, can fncn as a hydrogeon bond donor
Given several molecules that contain oxygen, how do you rank them in order of increasing boiling point?
For each molecule, count the number of oxygens. Each oxygen equals one hydrogen-bond acceptor.
Count the number of Hydrogens that are bonded to an N, O, or F. These are hydrogen donors.
Order the molecules according to the sum of hydrogen acceptors and hydrogen donors.
What does the solubility of a hydrocarbon depend on?
The polarity of the solute, and the polarity of the solvent.
The dipole moment of a hydrocarbon is:
(a) very small to zero
(b) moderate to very large
very small to zero
As a general rule, hydrocarbons containing [#] or fewer carbons have good solubility in water.
[What is the number?]
6
Nucleophilicity [increases/decreases] going down the periodic table within a particular group
increases
Chloride anion, hydroxyl group, ammonia, cyanide PAI, unattached hydroxyl PAI, ethane are examples of [nucleophiles/electrophiles]
nucleophiles
Nucleophilicity [increases/decreases] as electronegativity decreases.
Increases
What are electrophiles?
[TPRH has an excellent definition on p 478]
species that have a positive or partial positive charge and, frequently, have in incomplete octet
Electrophilicity [increases/decreases] as negative charge increases
decreases
Carbonium ions are also called __________.
carbocations
Most organic rxns proceed thru one of these 3 types of intermediate species:
carbocations;
alkyl radicals; or
carbanions
on the MCAT, __________ will always be sp2 hybridized with an empty p orbital
carbocations
on the MCAT, alkyl radicals will be ___ hybridized with the unpaired electrons in an unhybridized ___ orbital.
- sp*2;
- p*
What are alkyl radicals?
Rxn intermediates that contain 1 unpaired electron
Regarding the 3 rxn intermediates: the less substituted a/an _________ is, the more stable it is.
carbanion
What is a relationship between the reactivity of an alkyl radical and its degree of substitution?
The more substituted the alkyl radical is, the less reactive it is.
What is the relationship between the reactivity of a carbocation and its degree of substitution?
The more substituted the carbocation is, the less reactive it is.
What is the relationship between a carbanion’s reactivity and its degree of substitution?
The more substituted a carbanion is, the more reactive it is.
What is the relationship between an alkyl radical’s energy and its degree of substitution?
The higher the alkyl radical’s energy, the less substituted it is.
What is the relationship between a carbanion’s level of substitution and its energy?
The more substituted the carbanion is, the higher its energy
What are 4 common examples of electrophiles according to TPRH p. 478?
Hydrogen ion,
carbon that is double-bonded to oxygen,
carbocation, and
borane
what is the molecular formula of borane?
BH3
Generally, the major product of a rxn is derived from the [most/least] stable intermediate.
(p 479, TPRH)
MOST
What are the two major ways by which organic intermediates are stabilized?
Inductive effects, and
resonance effects
Functional groups or substituents that surround a reaction intermediate will pull electrons towards them (i.e., away from the intermediate) if they are [more/less] electronegative than the intermediate.
If the substituent is MORE electronegative than the intermediate
on the MCAT, alkyl substituents always [donate/withdraw] electrons to/from the rxn intermediate
donate electrons to the intermediate
[p 479; TPRH]
Name the electron-deficient intermediate(s) found in orgo.
Carbocations, and
radicals
Define the ‘inductive effect’
the stabilization of reaction intermediates by the sharing of electrons thru sigma bonds
What does it mean to say that an electron is localized?
‘localized’ means it is confined to one orbital, which can be either
a bonding orbital between 2 atoms, or
a lone-pair orbital
Resonance structures usually involve electrons that are adjacent to (i.e., 1 atom away from) a/an:
pi bond or an unhybridized p orbital
(p 485, TPRH)
What tells you that a resonance structure can NOT be drawn for a particular atom?
If the atom is sp3 hybridized, it cannot appear in resonance forms
A Bronsted-Lowry acid [donates/accepts] a ________
donates a proton
The hybridization of a triple bond (e.g., alkYnes) is [sp / sp2 / sp3].
sp
The most stable type of bond between atoms is [sigma / pi].
sigma
What does conjugation mean, in Orgo?
Alternating single and double bonds.
In organic chemistry, what does the term geminal mean?
refers to the relationship between two atoms or functional groups that are attached to the same atom
The [smaller / larger] the molecular weight, the [higher / lower] the density.
The ↓↓ the molecular WEIGHT, the ↓↓ the density.
Combustion reactions are [endothermic / exothermic / nonspontaneous].
EXOthermic
(1) The most stable cycloalkane has [#] carbons.
(2) The second most stable cycloalkane has [#] carbons.
6
5
In a radical reaction that has an Initiation, Propagation, and Termination steps, which of these steps feature homolytic bond cleavage?
Only the Initiation step has homolytic bond cleavage.
Order the Halogen radicals from MOST reactive to LEAST reactive.
F > Cl > Br > I
Which of the following is/are required for the Hydrogenation of an alkEne?
[Metal catalyst / high temperature / both / neither]
metal catalyst
T/F:
When an alkEne reacts with an hydrogen halide (H-X), but in the presence of peroxide, the resulting alkyl halide product will be anti-Markovnikov.
partially True.
The anti-Markovnikov effect, created by the presence of peroxide, only works with H**Br **reactants, and NOT with reactions that have HCl or HI as reactants.
When an alkEne reacts with an hydrogen bromide (HBr), but in the presence of peroxide, the resulting alkyl halide product will be anti-______.
Markovnikov
When an alkEne reacts with a hydrogen bromide (HBr), but in the presence of a _______, the resulting alkyl halide will be anti-Markovnikov.
peroxide
In an oxymercuration-demercuration reaction, the alcohol product that is formed is [Markovnikov / anti-Markovnikov].
Markovnikov
Are rearrangements (i.e., switiching Hydrogens or Methyl groups around) possible in an **oxymercuration-demercuration **reaction?
No
In hydroboration-oxidation reactions, the alcohol product is formed from the [syn / anti] addition, of an -OH and an H, to an alkene.
syn
In the hydrogenation of alkenes using a metal catalyst, the Hydrogens are added to the alkene in a **[syn / anti] **addition.
syn
EMR in the infrared (IR) range has a wavelength from ___ to ___ millimeters.
2.5 to 20 mm
In IR spectroscopy, what is wavenumber?
the reciprocal (inverse) of the wavelength at which the organic molecule’s covalent bonds will vibrate
In IR spectroscopy, wavenumbers are measured in this unit:
reciprocal centimeters (cm-1)
In a IR spectroscopy graph, what are the labels of the axes?
Y-axis: Transmittance
X-axis: Wavenumber
In IR spectroscopy, the carbonyl“stretch” is centered around what wavenumber?
1700 cm-1
In IR spectroscopy, the “stretch” for the alkene double bond is centered around what wavenumber?
1650
In IR spectroscopy, the triple bond“stretch” is centered around what wavenumber?
2600 - 2100
In IR spectroscopy, describe the -OH“stretch”:
very steep, and very broad
3600 - 3200
In IR spectroscopy, how do we tell apart the “stretch” of a aliphatic C-H bond, versus an aromatic C-H bond?
- aliphatic C-H bonds stretch at a little less than 3000;
- aromatic C-H bonds stretch at wavenumbers slightly greater than 3000
In IR spectroscopy, the “stretch” wavelength for any kind of C-H bond is around:
3300 - 2850
In IR spectroscopy, how do we distinguish the “stretch” of different types of C-H bonds?
- for sp3 carbons, the stretch is around 3000 to 2850
- for sp2 carbons, the stretch is around 3150 to 3000
- for sp carbons, the stretch is around 3300
What does shift or chemical shift mean when talking about NMR spectroscopy?
the location of the sets of peaks in the NMR spectrum
For hydrogen NMR spectroscopy, along which numerical value(s) on the X-axis will you find halogens?
3 - 5
For proton NMR spectroscopy, along which numerical value(s) will you find aromatics?
7
For proton NMR spectroscopy, along which numerical value(s) will you find carboxyl groups?
10 - 12
For proton NMR spectroscopy, along which numerical value(s) will you find aldehydes?
9 - 11
For hydrogen NMR spectroscopy, along which numerical value(s) on the X-axis will you find alkyne triple bonds?
~ 2
For hydrogen NMR spectroscopy, along which numerical value(s) on the X-axis will you find ketones?
1 - 2
For hydrogen NMR spectroscopy, along which numerical value(s) on the X-axis will you find **benzyl **groups?
~ 3
Which of the following cycloalkanes has the lowest heat of combustion, per —CH2— (i.e., methylene) group?
- cyclopropane
- cyclobutane
- cyclohexane
- cycloheptane
cyclohexane
The Iodoform Test is used for:
to detect the presence of a carbonyl group with a methyl group bonded to it. E.g., methyl ketones, and acetaldehyde will give a positive Iodoform test.
How do you know you have a positive Iodoform test?
The formation of a **yellow precipitate **
Organic (i.e., carboxylic) Acid + Alcohol → ????
→ ESTER + water
Alcohol + \_????_ → Ester + H20
organic (i.e., carboxylic) Acid
A saponification rxn involves reacting a ____ with a ____.
- inorganic base (e.g., NaOH);
- ester
Ester + inorganic Base → ????
→ Soap + alcohol
