MCAT Chemical and Physical Foundations of Biological Systems Flashcards: 5d Alcohols Carboxylic Acids Derivatives

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This deck focuses on 5d Alcohols Carboxylic Acids Derivatives, giving you a quick way to review the definitions, rules, and examples that matter most for MCAT Chemical and Physical Foundations of Biological Systems.

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Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: What is the general formula for an acid chloride (acyl chloride)?

Answer: $\text{R-COCl}$. Acid chlorides feature a carbonyl group bonded to a chlorine atom, with R as the alkyl substituent.

Flashcard 2: What is the general formula for an ester functional group?

Answer: $\text{R-COOR'}$. Esters comprise a carbonyl group attached to an alkoxy group, where R and R' are alkyl chains.

Flashcard 3: Which is more acidic: a typical carboxylic acid or a typical alcohol?

Answer: Carboxylic acid. Carboxylic acids have lower pKa values due to resonance stabilization of their conjugate bases compared to alcohols.

Flashcard 4: What is the general formula for an alcohol functional group attached to an alkyl chain?

Answer: $\text{R-OH}$. Alcohols feature a hydroxyl group bonded to a carbon atom in an alkyl chain, denoted by R representing the alkyl substituent.

Flashcard 5: What structural feature makes an alcohol capable of hydrogen bonding with water?

Answer: Polar $\text{O-H}$ bond (H-bond donor and acceptor). The electronegativity difference in the O-H bond creates polarity, enabling alcohols to donate and accept hydrogen bonds with water molecules.

Flashcard 6: Identify the oxidation product of a primary alcohol under mild oxidation conditions.

Answer: Aldehyde. Mild oxidants selectively convert primary alcohols to aldehydes by removing two hydrogens without further oxidation.

Flashcard 7: Identify the oxidation product of a primary alcohol under strong oxidation conditions.

Answer: Carboxylic acid. Strong oxidants fully oxidize primary alcohols to carboxylic acids by adding an oxygen and removing hydrogens.

Flashcard 8: Identify the oxidation product of a secondary alcohol under typical oxidation conditions.

Answer: Ketone. Secondary alcohols lose two hydrogens during oxidation, forming ketones due to the carbon's attachment to two alkyl groups.

Flashcard 9: What is the oxidation outcome for a tertiary alcohol under typical oxidation conditions?

Answer: No oxidation (unless C-C bond cleavage occurs). Tertiary alcohols lack the necessary hydrogen on the carbinol carbon for typical oxidation, preventing reaction unless bonds break.

Flashcard 10: What is the general formula for a carboxylic acid functional group?

Answer: $\text{R-COOH}$. Carboxylic acids contain a carbonyl and hydroxyl group on the same carbon, represented with R as the alkyl chain.

Flashcard 11: What is the conjugate base of a carboxylic acid called?

Answer: Carboxylate ($\text{R-COO}^-$). Deprotonation of the carboxylic acid's hydroxyl group yields the carboxylate anion, stabilized by resonance.

Flashcard 12: Identify the nucleophile that converts an acid chloride into an amide in one step.

Answer: Ammonia or an amine ($\text{NH}_3$ or $\text{RNH}_2$). Amines or ammonia act as nucleophiles, attacking the carbonyl and displacing chloride to form the amide bond.

Flashcard 13: Which functional group is formed when an acid derivative reacts with an alcohol via acyl substitution?

Answer: Ester. Alcohols serve as nucleophiles in acyl substitution, displacing the leaving group to yield esters.

Flashcard 14: Which functional group is formed when an acid derivative reacts with an amine via acyl substitution?

Answer: Amide. Amines function as nucleophiles, attacking the carbonyl and expelling the leaving group to produce amides.

Flashcard 15: What resonance feature stabilizes the carboxylate anion and increases acidity?

Answer: Negative charge delocalized over two oxygens. Resonance in the carboxylate ion distributes the negative charge across two oxygen atoms, enhancing stability and acidity.

Flashcard 16: What is the approximate $pK_a$ range for most simple carboxylic acids?

Answer: $pK_a \approx 4$ to $5$. The pKa reflects the strength of carboxylic acids, influenced by resonance stabilization of the conjugate base.

Flashcard 17: What is the approximate $pK_a$ range for most simple alcohols?

Answer: $pK_a \approx 16$ to $18$. Alcohols have higher pKa values because their conjugate bases lack resonance stabilization, making them weaker acids.

Flashcard 18: What is the general formula for an acid anhydride functional group?

Answer: $\text{R-CO-O-CO-R}$. Acid anhydrides consist of two acyl groups linked by an oxygen atom, often represented symmetrically for simplicity.

Flashcard 19: What is the general formula for an amide functional group?

Answer: $\text{R-CONH}_2$ (or $\text{R-CONR'}_2$). Amides have a carbonyl group bonded to a nitrogen atom, which may be substituted with hydrogens or alkyl groups.

Flashcard 20: What is the general formula for a carboxylate derivative called a thioester?

Answer: $\text{R-COSR'}$. Thioesters replace the oxygen in esters with sulfur, linking the carbonyl to a thioalkyl group.

Flashcard 21: Which acid derivative is most reactive toward nucleophilic acyl substitution?

Answer: Acid chloride. Acid chlorides have the best leaving group, chloride, making them highly susceptible to nucleophilic attack.

Flashcard 22: Which acid derivative is least reactive toward nucleophilic acyl substitution?

Answer: Amide. Amides possess a poor leaving group due to nitrogen's resonance donation, reducing reactivity in substitution reactions.

Flashcard 23: What is the standard reactivity order of acid derivatives toward nucleophilic acyl substitution?

Answer: Acid chloride $>$ anhydride $>$ ester $\approx$ thioester $>$ amide. Reactivity decreases with poorer leaving groups and increased resonance stabilization from the heteroatom.

Flashcard 24: Which leaving group is better in acyl substitution: $\text{Cl}^-$ or $\text{RO}^-$?

Answer: $\text{Cl}^-$. Chloride is a weaker base and better leaving group than alkoxide in acyl substitution reactions.

Flashcard 25: Identify the product when a carboxylic acid reacts with an alcohol under acid catalysis.

Answer: Ester (Fischer esterification). Acid catalysis protonates the carbonyl, enabling nucleophilic attack by alcohol and water elimination to form the ester.