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Description
Flashcards by JONATHAN ALEXANDER MARROQUIN, updated more than 1 year ago
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Created by JONATHAN ALEXANDER MARROQUIN
about 3 years ago
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| Question | Answer |
| Structural Isomerism | atoms are arranged in a completely different order. |
| Cis-Trans Isomers of Alkenes and E/Z Notation | cis- if the two alkyl groups are on the same side of the C=C. trans- if the two alkyl groups are on opposite sides of the C=C. |
| Absolute Stereochemistry (R) and (S) | Although these two molecules have the same physical properties, they rotate plane-polarized light in equal and opposite directions, a property called optical rotation. |
| Conformation and Energy (Newman Projections) | The degrees of freedom in a molecule. |
| Conformations of Cyclohexane and Energy (Boat, Twist-boat, Chair) | |
| Boat conformation of Cyclohexane | Created when two C atoms on opposite sides are both lifted up out of the plane creating a boat shape. The boat conformation is the least stable. |
| Twist-boat conformation of Cyclohexane | The boat form is flexible by twisting it at the bottom . Flagpole H's move farther apart and the eight hydrogens along the sides become more completely staggered. |
| Chair conformation of Cyclohexane | Most stable conformation due to less steric hinderance, all C-H bonds are staggered in the Newman Projection |
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Bond Polarity
Image:
Polar2 (binary/octet-stream)
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When the difference in electronegativity is very small or zero, the bond is covalent and nonpolar. When it is large, the bond is polar covalent or ionic. Partial charges are denoted as δ+ and δ-. |
| Electronegativity | The tendency of an atom in a molecule to attract the shared pair of electrons towards itself. Electronegativity increases from bottom left to top right i.e. F>Cs |
| Nucleophiles (NU-) | Electron-rich species, can be either be an anion or neutral atom with lone electron pairs. E.g. I-, Cl-, Br-. |
| Electrophiles (E+) | Electron-deficient species, can either be a cation or neutral atom with vacant valence shells. E.g. BH₃. |
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Addition reaction
Image:
Ear (binary/octet-stream)
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In addition reaction, a small molecule is added to multiple bond and one π bond is converted to two σ bonds . |
| Resonance Structures | Differ only in the arrangement of electrons; the atoms keep the same connectivity and arrangement. |
| heterolytic Cleavage | The uneven splitting of the bonding electrons (i.e. bonding electron pair), usually taken by the more electronegative specie, in which at least one ion is produced. An arrow with double-barbs indicates heterolytic cleavage |
| Homolytic Cleavage | The bonding electron pair (usually non-polar bonds), splits evenly to produce radicals, where energy is provided by light (hv) or heat (Δ) energy. Represented by half-barbed arrows |
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Electrophilic Addition (Acid Catalyzed Addition to a Double Bond)
Image:
Sd (binary/octet-stream)
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The alkene acts as the nucleophile that attracts and bonds to the electrophilic H from the acid to form a carbocation intermediate. An anion (Br-) then bonds to the carbocation forming the product (bromoethane). |
| Markovnikov's Rule | States the acidic H bonds to the carbon with more H's while the halide bonds to the carbon with higher alkyl substituents. |
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Carbocation Stability
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Carbo (binary/octet-stream)
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The carbon atom in the carbocation is electron deficient; it only has six valence electrons which are used to form three σ covalent bonds. The carbon has an unoccupied p orbital making it excellent Lewis acids. Stability: methyl<primary<secondary<tertiary |
| Regioselectivity in Electrophilic Addition | In the addition reaction for asymmetric alkenes, the dominant product is a direct result of the more stable carbocation intermediates formed. |
| Racemic Mixture | An equal mix of two enantiomers. |
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Identifying Oxidation State of Carbon
Image:
Eeeee (binary/octet-stream)
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If the atom bonded is less electronegative, the carbon gains a -1 charge If the atom is more electronegative, the carbon gains a +1 charge If the atom is another carbon then the charge remains 0. |
| Lewis Acids/Bases | Lewis acids accept an electron pair. Lewis Acids are Electrophilic. Cations are Lewis acids. An atom, ion, or molecule with an incomplete octet is Lewis acid. Molecules where the central atom can have more than 8 valence shell electrons are classified as Lewis acids. Molecules that have multiple bonds between two atoms of different electronegativities. Lewis Bases donate an electron pair. Lewis Bases are Nucleophilic. An atom, ion, or molecule with a lone-pair of electrons be a Lewis base. |
| Brønsted–Lowry Acid/Base | A Brønsted-Lowry acid is a proton donor. A Brønsted-Lowry base is any species that can accept a proton from another molecule. |
| Arrhenius acids/bases | An Arrhenius acid increases the concentration of hydrogen (H+) ions in an aqueous solution, while an Arrhenius base increases the concentration of hydroxide (OH–) ions in an aqueous solution. |
| Acid Catalyzed Addition of Oxygen Nucleophiles | Acid Catalyzed Addition of Oxygen Nucleophiles. The H of the acid deprotonates the alkene forming a carbocation intermediate. Then the nucleophilic R-O-H group attacks and bonds to the intermediate. Another R-O-H group attacks the bonded R-O-H and deprotonates it while oxygen atom gains the bonded pair of electrons to form the product and acid. If the 'R' is a H the product is an alcohol however, if its an alkyl the product is an ether. |
| Functional Groups | A specific grouping of elements that is characteristic of a class of compounds, and determines some properties and reactions of that class. |
| Sp3 Hybridization | Can form four sigma bonds with tetrahedral geometry |
| Sp2 Hybridization | Can form three sigma bonds with trigonal planar geometry |
| Sp Hybridization | Can form two sigma bonds |
| Linear Combination of Atomic Orbitals (LCAO) | The Linear combination of atomic orbitals is an approximate method for representing molecular orbitals. It’s more of a superimposition method where constructive interference of two atomic wave function produces a bonding molecular orbital whereas destructive interference produces non-bonding molecular orbital. |
| Acidity of Functional Groups: Inductive Effect | Is the charge dispersal effect of electronegative atoms through σ bonds. The effect is addictive; more chlorine atoms have an overall stronger effect, therefore increasing acidity from mono, to di-, to tri-. |
| Acidity of Functional Groups: Hybridization | For the anion with more s character (^%), the electrons are closer to the nucleus and experience stronger attraction, therefore the anion has lower energy and is more stable therefore, a weaker conjugate base but stronger acid. |
| Acidity of Functional Groups: Resonance | Resonance may delocalize the electron pair that the base might use to form a new bond with the proton. This delocalization increases the stability of the base which results in lower reactivity. A base that has resonance delocalization of the electron pair that is shared with the proton will therefore be less basic. |
| Saturated Hydrocarbons | Has all sigma bonds. E.g. Alkane |
| Unsaturated Hydrocarbons | Has double or triple bonds. E.g. Alkenes, Alkynes |
| Sigma star (σ*) | Normally this orbital is empty, but if it should be occupied, the wave nature of electron density is out of phase and canceling in nature. There is a node between the bonding atoms. |
| Pi star (π*) | Normally this orbital is empty, but if it should be occupied, the wave nature of electron density is out of phase and canceling in nature. There is a node between the bonding atoms. |
| Fats | Fatty acid chains in Fats have single bonds Since it has carbon bonds that are single, the molecular structure is robust and strong. The intermolecular forces are not weak. Hence, a fat remains solid |
| Oils | Oils have double-bonded carbon atoms and therefore unsaturated. Since it has double bonds, the lack of hydrogen atoms reduces the strength of the intermolecular forces. Hence oil remains liquid - the binding is not that strong. |
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