Organic Chemistry Exam 1
What atoms act as nucleophiles?
-All negative charged species -Heteroatoms with lone pairs
What atoms act as electrophiles?
-All positive charged species -Metal atoms attached to electronegative species
Describe the Resonance Effect
-The more stable the anion formed through dissociation of the acid the stronger the acid -Resonance stabilizes anions
Describe the Inductive Effect
-The polarization of electron density transmitted through nearby covalent bonds -The more electronegative the atoms covalently bonded to the anions the more the negative charge is distributed throughout the anion thus stabilizing it -Stabilizing the anion increases the strength of the acid
Describe what goes into an energy diagram
-graph of change in energy that occurs as reaction takes place -energy is plotted on the y-axis -position of atoms (rxn coordinates) is plotted on the x-axis -enthalpy is the difference in energy between the products and reactants -Transition States is a point at which an energy maximum or local maximum occurs -Intermediate occurs between two transition states
pKa = ???
-logKa
What do all single bonds consist of?
1 sigma bond
What do all double bonds consist of?
1 sigma bond and 1 pi bond
What do all triple bonds consist of?
1 sigma bond and 2 pi bonds
When naming organic compounds, what are the strict rules regarding punctuation?
1. A comma is used to separate two numbers 2. A hyphen is used to separate a number from a letter
What is the bond angle of a sp^3/tetrahedral?
109.5 degrees
What is the bond angle of a sp^2/trigonal planar?
120 degrees
What is the bond angle of a sp/linear molecule?
180 degrees
How do you calculate degree of unsaturation?
2 ( # carbon ) + 2 + ( # nitrogen ) - ( # hydrogen ) - ( # halogen ) / 2
Properly punctuate this organic compound. 3ethyl245trimethylhexane
3-ethyl-2,4,5-trimethylhexane
What is an anhydride?
A compound where 2 carbonyl carbons are separated by an oxygen.
What are anhydrides?
A functional group characterized by two acyl groups joined by an oxygen atom
Define Acids and Bases in Branstead-Lowry terms.
Acid: proton (H+) donor Base: proton (H+) acceptor
Nomenclature Rule 1
Determine the longest continuous chain of carbon atoms. Use the name of this chain as the stem chain of compound
What is a molecule called when it only has C-C single bonds?
Alkane (saturated)
What are aldehydes?
An organic compound containing one or more -CHO groups. The general formula is RCHO where R is a hydrocarbon group or simply hydrogen.
What is the saturation of C4H10, C5H12, and C5H10
C4H10: completely saturated C5H12: completely saturated C5H10: 1 degree of unsaturation - 1 double bond - 1 ring
What is the saturation of C4H6 and C3H7Cl
C4H6: 2 degrees of unsaturation -2 double bonds -1 triple bond -1 ring and 1 double (2 rings)
What are carbonyl groups?
C=O
What is a carbonyl?
C=O
Arrange the compounds in order of decreasing pKa, highest first. -ClCH2CH2OH -CH3CH2OH -Cl2CHCH2OH
CH3CH2OH, ClCH2CH2OH, Cl2CHCH2OH
How do you calculate activation energy?
Ea = Peak energy - Initial energy
What is the heat of reaction called?
Enthalpy (delta H)
List all halogens
F, Cl, Br, I, At, Ts
What are the halogen substituents?
F: fluro Cl: chloro Br: bromo I: iodo (are treated like alkyl substituents)
True/False: Alkanes are not completely saturated?
False -Alkanes are completely saturated (Aliphatic)
True/False: Alcohols can have quaternary structures?
False -alcohols cannot have quaternary structures
Which is more acidic: CH4 vs H2O
H2O
Which is more acidic: HCl vs HBr
HBr
List the strong acids
HCl, HBr, HI, HNO3, H2SO4, HClO4
What is a constitutional Isomers?
Have the same structural formula but a different attachment of atoms
What does the RDS look like on the energy diagram?
Highest peak (slow rxn)
What is the equilibrium constant?
K = (concentration of products) / (concentration of reactants)
list of strong bases
LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2, Ba(OH)2
What is quaternary structure and what does it look like?
Molecule (ex.OH) is attached to a carbon that is bonded to four other carbons
What is a primary structure and what does it look like?
Molecule (ex.OH) is attached to a carbon that is bonded to only one carbon molecule
What is a tertiary structure and what does it look like?
Molecule (ex.OH) is attached to a carbon that is bonded to three other carbons
What is a secondary structure and what does it look like?
Molecule (ex.OH) is attached to a caron that is bonded to two other carbons
Nomenclature Rule 2
Name all substituents attached to the stem chain. The name of the substituents is determined by the number of carbons in the branch. Prefix for the number of carbons is followed by the suffix -yl
Characterize the following atoms as being either nucleophilic or electrophilic. -H2S -(+)CH3 -H(+) -I(-) -MgO -AlCl3
Nucleophilic: I(-), H2C Electrophilic: (+)CH3, MgO, AlCl3, H(+)
Nomenclature Rule 3
Number the stem chain closest to the substituent. When numbering results in a tie for the 1st substituent the substituent of lowest alphabetical order takes precedence
What compound is bonded to a carbon chain that makes the molecule an alcohol?
OH
Common name: what does the stem chain look like
R
What does a hydroxyl (found in alcohols) look like?
R-O(two lone pairs)-H
What are haloalkanes?
Saturated organic compounds that contain carbon atoms and at least one halogen atom
What happens when the stem chain of the molecule contains more carbons than the cyclic portion?
The cyclic portion becomes the substituent, cyclo is used in alphabetizing
What is the Activation Energy (Ea)?
The difference between the reactants and the transition state (intermediate and transition state)
Describe how to assess acidity?
Step 1: Effect of Electronegativity -The more electronegative the atom to which the acidic proton (hydrogen) is attached the more polar the bond and more acidic the proton Step 2: Effect of Hybridization -The more s character an atom has the more electronegative that atom hence making that proton more acidic Step 3: Effect of size of atom -The larger the size of the atom attached to the acidic proton the more acidic it it
What is an alkyne?
Straight or branched chain hydrocarbons that have one or more triple bonds
What is an aldehyde?
Terminal group with a carbon double-bonded to an oxygen. (R-CO-H)
What does the Ka value mean for an acid?
The higher the Ka value the stronger the acid
What does the size of an atom effect?
The larger the size of the atom attached to the acidic proton the more acidic it is
How can you calculate the number of hydrogens in a bond line diagram?
The number of carbons x 2 + 2 (in every non ring linear single bond structures)
What does the pKa value mean for an acid?
The smaller the pKa the stronger the acid
True/False: Carboxyl groups found in carboxylic acids are always primary
True
True/False: Water is amphoteric
True
How do you name cycloalkanes?
Use the preprefix cyclo- followed by the name representing the number of carbon atoms in the ring
Nomenclature Rule 3.2
When there are two longest chains of the same length - choose the chain with the greatest numbers of substituents as the stem chain
What is a ketone?
a functional group with the structure R ( C=O) R', where R and R' can be a variety of carbon containing substituents
What is a nucleophile?
a base that can donate a pair of electrons
What is an alkene?
a class of hydrocarbons; unsaturated compounds with at least one carbon-carbon double bond
What are chemical reaction mechanisms?
a step by step description of how the reaction takes place?
A strong acid and a strong base will form what?
a weaker acid and a weaker base
Nomenclature Suffix -oic
acid
Nomenclature Suffix -al
aldehyde
Which compounds contain a carbon and oxygen double bond?
aldehyde, ketone, carboxylic acid, ester, anhydride, amide
What is another name for primary carbonyls?
aldehydes
Which compounds contain only carbon and hydrogens?
alkane, alkene, alkyne
Which type of compound contains at least one carbon-carbon double bond?
alkene
What is another name for haloalkanes?
alkyl halides
Nomenclature Suffix -amino
amine
Where are amino acids found?
amines
What is an electrophile?
an acid that can accept a pair of electrons
What is a heteroatom in organic chemistry?
an atom that is not carbon or hydrogen
What is an ester?
an organic compound formed by the reaction between a carboxylic acid and an alcohol (triglycerides)
What is a carboxylic acid?
any compound containing a carbonyl with a hydroxyl substituent on the carbonyl carbon
What is an amide?
any compound containing a carbonyl with an amine substituent on the carbonyl carbon
What is an aromatic?
are derivatives of a benzene ring
What is curved arrow formalism?
arrow starts at a set of electrons and goes where the electron goes
What are the groups attached to the stem chain known as?
branches and are called substituents
Nomenclature prefix for 4
but-
What does amphoteric mean?
can act as an acid or a base
What does R mean in a molecule?
carbon chain
Strong acids _____ dissociate, while weak acids ______ dissociate
completely, partially
What is a thiol?
contain a sulfur bonded to one hydrogen and one carbon
What is a sulfide?
contain a sulfur bonded to two different carbon atoms
What is an ether?
contain an oxygen bonded to two different carbons
What is a cycloalkene?
contain at least one double bond in the ring
Nomenclature Infix -yn- meaning
contain carbon-carbon triple bond
Nomenclature Preprefix cyclo- meaning
contains a ring
Nomenclature Infix -en- meaning
contains carbon-carbon double bonds
Nomenclature prefix for 10
dec-
What is the equation for Gibbs Free Energy in Thermodynamics?
delta G degree = -RTInK
How do you calculate the heat of reaction?
delta H = Final energy - Initial energy
Nomenclature prefix for 12
dodec-
What is the amount of disorder (randomness) called?
entropy (delta S)
Identify the functional group present in the following compound, 3-methylbutyl acetate.
ester
Nomenclature prefix for 2
eth-
What are the halides?
fluoride, chloride, bromide, iodine
What does halo stand for?
halide
Nomenclature prefix for 7
hept-
Nomenclature prefix for 6
hex-
Nomenclature Suffix -e meaning
hydrocarbon
Nomenclature Suffix -ol
hydroxyl
What is a cyano group?
if formed by a carbon triple bonded to a nitrogen
Which direction will the equilibrium go with a strong acid?
it will always lie away from the strongest acid
Nomenclature Suffix -one
ketone
What is another name for a secondary carbonyl?
ketone
Nomenclature prefix for 1
meth-
What are all the common names?
neopentyl, isopropyl, n-propyl, isobutyl, sec-butyl, tert-butyl, isopentyl
Nomenclature prefix for 9
non-
Nomenclature prefix for 8
oct-
Nomenclature Infix -an- meaning
only carbon-carbon single bonds
What are hydrocarbons?
organic molecules consisting of only carbon and hydrogen
Nomenclature prefix for 5
pent-
Nomenclature prefix for 3
prop-
Which is more important/stronger: resonance or inductive?
resonance
What does a very fast rxn look like on the energy diagram?
small peak
How are the substituents named?
start numbering at the substituents of lowest alphabetical order than go towards the next closest branch
What does a low PKa mean?
strong acid
What does PKA stand for?
tendency an acid has to give up proton
In the IUPAC system what does the suffix tell us?
the functional group attached
In the IUPAC system what does the infix tell us?
the name (kind) of the carbon-carbon bonds
In the IUPAC system what does the prefix tell us?
the number of carbons in the carbon chain
What does a positive delta H mean?
the reaction is endothermic (heat is consumed)
What does a negative delta H mean?
the reaction is exothermic (heat is the product)
If delta G degree is negative what is favored? (Gibbs)
the reaction is favored
What is thermodynamics?
the study of energy transformations
What is kinetics?
the study of the rates of chemical reactions
What is the rate determining step (RDS)?
the transition state of the highest energy
Nomenclature prefix for 11
undec-
Nomenclature Rule 4
use both the number of the substituents and its alkyl name. When there are two or more of the same substituents use the prefix (di, tri, tetra, penta) are used however there prefixes are not used in alphabetizing substituents are listed in alphabetical order with their number preceding the stem name
What does a high PKa mean?
weak acid
