Organic Chemistry Chapter 2

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Alkanes
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entirely single bonds between carbons and hydrogens
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Alkenes
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has a double bond and sp2 hybridization between some C and hydrogens
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Alkynes
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has a triple bond between some carbon and hydrogens, sp hybridized
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What is the difference between benzene aromatic compound and toluene compound?
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Toluene has a methyl added to one of the Carbons in the ring
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What determines a dipole moment?
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It is determined by the magnitude and direction of the individual bond dipole moments. It is determined by vector quantities.
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True or False, Cis and Trans isomers have the same dipole moments?
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False, they have different physical properties including their dipole moments
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What do functional groups typically contain?
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They typically contain multiple bonds, unshared pairs of electrons, and non-carbon atoms -usually where the reaction take place
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Name 5 different Alkyl groups.
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Methyl, Ethyl, Propyl, Butyl, isobutyl
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What is the Methyl group?
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Me- CH3-
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What is the Ethyl group?
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Et- CH3CH2-
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What is the Propyl group?
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Pr- CH3CH2CH2-
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What is the Butyl group?
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Bu- CH3CH2CH2CH2-
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What is the Isobutyl group?
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iBu- CH3CH2CH (-) CH3
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What is a Phenyl group?
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Ph- C6H5
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What is a Benzyl gropu?
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Bn- C6H5CH2- -it is a phenyl group with a methylene group attached
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What is a primary carbon haloalkane?
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It is an alkyl halide with the “R” group and two “H”s on the carbon baring the halo-atom
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What is a secondary carbon haloalkane?
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It is an alkyl halide with two “R” groups and one “H” attached to the halo-atom bearing carbon
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What is a tertiary carbon haloalkane?
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It is an alkyl halide with three “R” groups and no “H”s attached to the halo-atom bearing carbon
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What is the functional group in an Alkyl Halide?
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The functional group is a halogen attached to a Carbon.
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What is considered a heteroatom?
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an atom other than carbon
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What is the functional group in Alcohols and Phenols?
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The functional group is an -OH group, hydroxyl group
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What is an Ether?
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they are the groups of an oxygen with two other R groups attached R-O-R or R-O-R’
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What is the functional group in an Ether?
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The functional group is a central sp3 hybridized oxygen attached to other alkyl groups, the oxygen also has two unshared pairs of electrons
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What is a cyclic ether?
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An ether where the oxygen is part of a ring, example is tetrahydrofuran which is a common solvent
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What is an amine?
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It is a organic derivative of ammonia, it has an sp3 hybridized nitrogen with an unshared pair of electrons, what is unique it it’s different nomenclature
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How to distinguish Amine groups? (nomenclatures)
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primary amine has one R group attached to the Nitrogen, secondary amine has two R groups attached to the N, tertiary amine has three R groups attached to N
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What is the characteristic functional group of an Aldehyde and a Ketone? Whats the difference?
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The functional group is a carbonyl group (C=O), an aldehyde is a carbonyl group attached to only one other C (R) group, it appears at the end of Carbon chains, the ketone group is the carbonyl group attatched to two other Carbons, appears in the middle of a chain
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What is the characteristic functional group of Carboxylic Acids, Esters, and Amides?
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The functional group is a carbonyl group derivatives
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What is an Carboxylic Acid?
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It is an acid, gives proton, made from an carboxylic group (carbonyl and hydroxyl) attached to an R group
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What is an Ester?
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They contain the carbonyl group and the oxygen from a hydroxyl group without the hydrogen, they can be obtained from carboxylic acids in a process called esterification, have another R group instead of the H -C(=O)-O-R
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What is esterificaiton?
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the process of going from a carboxylic acid to an ester by adding an alcohol R-O-H and an acid catalyst
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What is an Amide?
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it contains a carbonyl group attached to a NH2 group, the N can be further alkylated or arylated, (carbonyl attached to amine group)
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What is a Nitrile?
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It is a nitrile or cyano group, R-C=_N:, a carbon triple bonded to a nitrogen which has a lone pair attached
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What is the boiling point of Water? and Molecular Weight?
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Water boils at 100*C, with MW= 18
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What does the boiling point do as you gain molecular weight? Example is from Methane to Pentane?
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The boiling point rises because of the increasing molecular weight
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What are 3 intermolecular forces?
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dipole-dipole forces, Hydrogen bonding, London/Van der Waals forces
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What are Dipole Dipole interactions?
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They result from the attraction of a partial positive end of a polar molecule with the partial negative end of another polar molecule, create polar-covalent bonds
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What is Hydrogen bonding?
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It is the Dipole bonding that results from a Hydrogen attached to a highly electronegative atom (FON), there are hydrogen bonding in alcohols, this creates 3D networds of molecules, bond strength is 5kcal/mol
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What is London or van der Waals forces?
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They result form electrons of nonpolar molecules momentarily causing a charge imbalance, which forces surrounding molecules to have a charge imbalance, inducing a temporary dipole
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What is the order of attraction strength in the intermolecular forces?
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H-bonding is strongest by a long shot, then dipole-dipole, then London
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What is the trend with boiling point?
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the greater the molecular weight, the greater the number of electrons, the greater the London forces, and the greater the boiling point
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What is something in alkanes that causes the boiling point to lower?
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Branching decreases the surface area of London forces between alkanes and since they have less of a chance to have dipole moments, they boil easier
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What is true about alkanes boiling point trend?
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As the size of the alkane increases, the boiling point increases
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Alcohols have a higher boiling point than Alkanes and Ethers? True or False and explain.
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Alcohols have a higher boiling point than ether and alkanes because they form hydrogen bonds, ethers lack a hydrogen attached to an electronegative atom
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Which type of Amines form hydrogen bonds and why?
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Secondary and Primary Amines because it means there is still an Hydrogen attached to the central N
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What is the general trend of melting point?
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Melting point increases as the molecular weight increases.
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What is the rule of solubility?
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polar compounds dissolve in polar solvents, non-polar compounds dissolve in non-polar solvents
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Which one has a higher boiling point and why? Alkyne or Alkene with the same number of carbons?
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An alkyne has a high boiling point because the triple bond is more polarizable then the double bond in alkenes which leads to stronger London forces, also the triple bond is more linear than the double bond which allows the molecule to more readily interact
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What type of alkyne specifically has a higher boiling point?
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Internal Alkynes have higher boiling points over terminal alkynes because they provide more linearity to the molecule which enables more contact between molecules
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What are 3 Characteristics of Functional Groups?
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1. multiple bonds 2. unshared electrons 3. heteroatoms
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What is infared spectroscopy used to determine?
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They are used to determine the kinds of functional groups in an organic compound based off of the absorptions of the compounds that corresponds to the bond vibrations
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Two different types of bond vibrations?
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The stretch vibration is a change in bond length, it occurs at a higher frequency, the bend vibration is the change in bond angle, and this occurs at a lower frequency
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What kind of mount do you use in IR spec?
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Use a salt mount such as NaCl, without any water, because salt does not absorb IR radiation
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What is considered the functional group region in IR spec?
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The region is from 4,000 to 1,400 cm-1, or wavenumbers, it is the stretching region
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What is considered the fingerprint region in IR spec?
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This is the region from 1,400 to 600 cm-1, or wavenumbers, it is the bending region
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What does the intensity of IR absorption depend upon?
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The intensity depends on the polarity of the bond and the number of bonds
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What order to hybridized orbitals appear on IR spectra?
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sp first (higher frequency), then sp2, then sp3
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What is the general order of functional group appearance on IR spectra?
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small functional groups, strong functional groups, weaker functional groups, then heavy/strongly coupled atoms in fingerprint region
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What is Hookes’ Law?
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his law states that stronger bonds and lighter atoms give rise in an IR spectra at higher frequencies
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Where do bonds of lighter atoms vibrate in relation to bonds of heavier atoms?
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bonds of lighter atoms vibrate at higher frequencies than those of heavier atoms because lighter atoms have less inertia to overcome
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What frequency does O-H bond appear?
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3400 (strong, broad)
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IR stretch of N-H
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3300 (medium, broad)
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IR stretch of C-H
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3000 (medium)
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IR stretch of C=_N
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2250 (medium)
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IR stretch of C=_C
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2150 (medium to weak)
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IR stretch of C=O
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1700 (very strong)
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IR stretch of C=C
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1650 (medium)
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IR stretch of C-O
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1100 (strong)
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IR stretch of N-H
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3300 (medium, broad)

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