Organic Chemistry: Isomerism, Acidity, and Reaction Mechanisms

Comprehensive vocabulary flashcards covering organic chemistry concepts such as chirality, pKa, acid-base electronic effects, reaction energetics, carbocation stability, and alkene addition rules.

Chiral (quirales)

Molecules that are not superimposable on their mirror image.

Achiral (aginal/aquiral)

Molecules that are superimposable on their mirror image and lack chirality.

Cis/Trans Isomerism

A form of stereoisomerism describing the relative orientation of functional groups within a molecule.

Chiral Center (centro quiral)

An atom, typically carbon, that is bonded to four different groups.

Protonated State

The state of a molecule when the $pH < pK_a$, resulting in the addition of a proton ($H^+$).

Deprotonated State

The state of a molecule when the $pH > pK_a$, resulting in the loss of a proton.

Equilibrium Direction

In an acid-base reaction, the equilibrium shifts toward the side of the weaker acid or base.

Relative Acidity: $H_2O$ vs $H_2S$

$S$ is larger than $O$ and stabilizes a negative charge better; therefore, $H_2S$ is a stronger acid (higher $K_a$, lower $pK_a$) than $H_2O$.

Resonance (Resonancia)

A mechanism that delocalizes electrons and stabilizes a chemical system.

Inductive Effect (efecto inductivo)

The redistribution of electron density through sigma bonds due to the electronegativity of nearby atoms; it depends on the identity, quantity, and distance of the atoms.

Acidity and Hybridization

The acidity of hydrocarbons follows the orbital character order: $sp > sp^2 > sp^3$.

Electrophile (electrófilo)

An electron-deficient species that acts as an electron-pair acceptor.

Nucleophile (nucleofilo)

An electron-rich species that acts as an electron-pair donor.

Carbocation ($C^+$)

A reactive intermediate with a positively charged carbon atom.

Carbanion ($C^-$)

A reactive intermediate with a negatively charged carbon atom.

Enthalpy of Reaction ($\triangle H$)

Calculated as the difference between the enthalpy of products and reactants: $\triangle H_{\text{prod}} - \triangle H_{\text{react}}$. A negative value is exothermic, while a positive value is endothermic.

Spontaneous (Espontáneo)

A reaction that favors the formation of products under given conditions.

Carbocation Stability Order

The order of stability is tertiary ($3^\text{o}$) > secondary ($2^\text{o}$) > primary ($1^\text{o}$) > methyl ($met\text{í}lico$).

Allylic (al ext{í}lico) and Benzylic (benz ext{á}tico)

Positions that are highly stable because they can be stabilized through resonance.

Rearrangement (rearreglo 1,2)

A process where a hydrogen or alkyl group shifts to an adjacent carbon to generate a more stable carbocation.

Alkenes (Alquenos)

Hydrocarbons characterized by at least one carbon-carbon double bond, representing a type of unsaturation.

Geminal

Refers to two functional groups or substituents bonded to the same carbon atom.

Vinylic (Vin ext{í}lico)

A position or substituent located directly on a carbon atom that is part of a double bond.

Markonikov Product

The major product of an addition reaction where the nucleophile adds to the more substituted carbon (stable carbocation path).

Anti Markoniker

An addition reaction outcome where the substituent adds to the less substituted carbon atom of a double bond.

Activation Energy ($E_a$) and Stability

A more stable carbocation results in a lower $E_a$, leading to a faster reaction rate.