Organic Chemistry Exam #1 Review

Vocabulary terms from Exam 1... General Chemistry review, molecular representations, acids & bases, and alkanes & cycloalkanes

Formal Charge

The charge assigned to an atom in a molecule, such as the $+1$ charge found on the central nitrogen atom in an ammonium ion structure.

Constitutional Isomers

Compounds that have the same molecular formula but differ in the connectivity of their atoms.

Propranolol

An antihypertensive drug containing an oxygen atom with $sp^3$ hybridization, bent molecular geometry, and an approximate bond angle of $109.5^\circ$.

Dipole Moment

A measure of molecular polarity produced by the separation of charges, often used to rank compounds like fluorinated alkenes.

Partial Charges

Non-integer charges represented by $\delta+$ and $\delta-$ that denote the distribution of electron density in a polar bond such as $P-Cl$.

Aspartame

An artificial sweetener used in Equal® and diet beverages containing aromatic, amide, and carboxylic acid functional groups.

Aromatic Group

A functional group characterized by a planar, cyclic ring of resonance-stabilized atoms, identified as Group I in the structure of Aspartame.

Amide

A functional group consisting of a nitrogen atom attached to a carbonyl group ($C=O$), identified as Group II in Aspartame.

Carboxylic Acid

A functional group consisting of a carbonyl group bonded to a hydroxyl group ($-COOH$), identified as Group III in Aspartame.

Bond-line Structure

A representation of molecular structure where lines represent carbon-carbon bonds and carbons are located at every corner and end of a line.

Resonance Structures

Two or more valid Lewis structures for the same compound that differ only in the placement of electrons, as seen in compound $HN_3$.

Brønsted-Lowry Acid-Base Reaction

A reaction characterized by the transfer of a proton ($H^+$) from an acid to a base.

Conjugate Base

The species that remains after a Brønsted-Lowry acid has donated a proton.

Curved Arrows

A notation used in chemistry mechanisms to show the movement of electron pairs, starting from an electron-rich site and moving to an electron-poor site.

Substituent

An atom or group of atoms that branch off from the main parent chain or ring of a molecule.

Hydrogen Bonding

The strongest intermolecular force possible between molecules of alcohols like 1-butanol due to the presence of the $O-H$ group.

London Dispersion Forces

Weak intermolecular forces present between all molecules, including non-polar hydrocarbons.

Chair Structure

A common conformation of cyclohexane used to identify the spatial relationship of substituents as either cis or trans.

cis (configuration)

A relationship where two substituents on a ring structure are positioned on the same side.

trans (configuration)

A relationship where two substituents on a ring structure are positioned on opposite sides.

IUPAC Nomenclature

A systematic method of naming chemical compounds, such as 3,6-dimethyloctane or 1-tert-butyl-3-methyl cyclooctane.

Bicyclo Alkane

A polycyclic compound containing two joined rings, such as bicyclo [4.3.2] undecane.

Newman Projection

A way of looking down a specific carbon-carbon bond (such as the $C2-C3$ bond in butane) to visualize different energy conformations.

Anti-conformation

The lowest energy conformation of a molecule like butane as seen in a Newman projection, where large groups are $180^\circ$ apart.

Constitutional Isomers

Compounds that share the same molecular formula but differ in their atomic connectivity.

Nonpolar Covalent Bond

A bond type characterized by the equal sharing of electrons, specifically seen in the bond between carbon and hydrogen ($C-H$).

Formal Charge

The charge assigned to an atom in a molecule, calculated based on valence electrons, lone pairs, and bonded electrons; for example, a carbon atom bound to three other carbon atoms with no lone pairs or hydrogens has a formal charge of $+1$.

Trigonal Planar

A molecular geometry associated with $sp^2$ hybridized atoms that have three bonding regions and no lone pairs.

Localized Lone Pair

An electron pair that is specifically associated with one atom and does not participate in resonance.

Delocalized Lone Pair

An electron pair that is capable of moving via resonance and is not confined to a single atom.

Inductive Effect

The withdrawal or donation of electron density through sigma bonds due to electronegativity or formal charges, which can stabilize a conjugate base and increase the acidity of a proton.

Resonance Stabilization

The stabilization of a molecule or ion (such as a conjugate base) by spreading the charge over multiple atoms through pi systems.

Cis isomer (Chair Structure)

A configuration where two substituents on a cyclohexane ring point in the same relative direction (both up or both down).

Trans isomer (Chair Structure)

A configuration where two substituents on a cyclohexane ring point in opposite relative directions (one up and one down).

Methyl Cation ($CH_3^+$) Orbitals

A species where the $C-H$ bonds result from the overlap of a carbon $sp^2$ orbital and a hydrogen $s$ orbital.

Amide

A functional group characterized by a nitrogen atom bonded to a carbonyl carbon ($C=O$).

Amine

A functional group consisting of a nitrogen atom with a lone pair, bonded to carbons or hydrogens via single bonds.

Half-chair

The least stable conformation of the cyclohexane ring due to high torsional and angle strain.

Curved Arrow Mechanism

A formal notation used to show the movement of electrons; arrows must start at an electron source (lone pair or bond) and point toward an electron sync (atom or bond).

Bicycloalkane

An alkane containing two fused rings, named using the format bicyclo[x.y.z]alkane based on the number of carbons in the bridges between bridgehead atoms.

Eclipsed Conformation

A higher-energy conformation where the bonds and atoms on adjacent carbons are aligned with each other when viewed down a carbon-carbon bond.

Newman Projection

A visual tool used to examine the conformations of a molecule by looking directly down a specific carbon-carbon bond.