Organic Chemistry

Cards (24)

• 1
  Front

  What is a functional group in organic chemistry?

  Back

  A specific atom or group of atoms within a molecule that is responsible for the characteristic chemical reactions of that molecule.

• 2
  Front

  What is the general formula for an alkane, and what is its functional group?

  Back

  General formula: CnH2n+2. Alkanes contain only C-C and C-H single bonds; they have no functional group (they are saturated hydrocarbons).

• 3
  Front

  What functional group defines a carboxylic acid, and what is its general representation?

  Back

  The carboxyl group (-COOH), consisting of a carbonyl (C=O) and a hydroxyl (-OH) bonded to the same carbon.

• 4
  Front

  In IUPAC nomenclature, what suffix is used for ketones, and how is the carbonyl carbon position indicated?

  Back

  The suffix -one is used. The position of the carbonyl carbon is indicated by a locant (e.g., pentan-2-one).

• 5
  Front

  What is the IUPAC rule for numbering the parent chain when naming branched alkanes?

  Back

  Number the longest carbon chain from the end that gives the substituents the lowest possible locants.

• 6
  Front

  What is constitutional (structural) isomerism?

  Back

  A type of isomerism where compounds have the same molecular formula but differ in the connectivity (bonding sequence) of their atoms.

• 7
  Front

  What is the difference between cis and trans isomers?

  Back

  Cis isomers have two identical or similar groups on the same side of a double bond or ring; trans isomers have them on opposite sides. These are geometric (configurational) isomers.

• 8
  Front

  What are enantiomers?

  Back

  Non-superimposable mirror-image stereoisomers of each other. They have identical physical properties except for the direction they rotate plane-polarized light.

• 9
  Front

  What is the SN2 reaction mechanism?

  Back

  A bimolecular nucleophilic substitution where the nucleophile attacks the back of the electrophilic carbon simultaneously as the leaving group departs, in a single concerted step, with inversion of configuration (Walden inversion).

• 10
  Front

  What is the rate law for an SN2 reaction?

  Back

  Rate = k[substrate][nucleophile]. The reaction is second-order overall, depending on the concentrations of both the substrate and the nucleophile.

• 11
  Front

  What is the SN1 reaction mechanism?

  Back

  A unimolecular nucleophilic substitution that proceeds in two steps: (1) ionization of the leaving group to form a carbocation intermediate, then (2) nucleophilic attack on the carbocation.

• 12
  Front

  Why do SN1 reactions produce racemic mixtures (or partial racemization)?

  Back

  Because the carbocation intermediate is planar (sp2 hybridized), the nucleophile can attack from either face, yielding both enantiomers, typically as a racemic mixture.

• 13
  Front

  What structural feature of the substrate favors SN1 over SN2?

  Back

  Tertiary substrates favor SN1 because the tertiary carbocation intermediate is stabilized by hyperconjugation and inductive effects, while steric hindrance slows SN2.

• 14
  Front

  What is the E2 elimination mechanism?

  Back

  A concerted, bimolecular elimination where a base abstracts a beta-hydrogen simultaneously as the leaving group departs and a pi bond forms. It is second-order: Rate = k[substrate][base].

• 15
  Front

  What stereoelectronic requirement must be met for an E2 reaction?

  Back

  The beta-hydrogen and leaving group must be anti-periplanar (dihedral angle of 180°) to allow proper orbital overlap during the concerted elimination.

• 16
  Front

  What is the E1 elimination mechanism?

  Back

  A two-step unimolecular elimination: (1) the leaving group ionizes to form a carbocation, then (2) a base removes a beta-hydrogen to form the alkene. Rate depends only on substrate concentration.

• 17
  Front

  What does Zaitsev's rule predict about elimination reactions?

  Back

  The major product of an elimination reaction is the more substituted (more stable) alkene, formed by removal of the hydrogen from the more substituted beta-carbon.

• 18
  Front

  What is Markovnikov's rule in addition reactions?

  Back

  In electrophilic addition of HX to an alkene, the hydrogen adds to the carbon bearing more hydrogens (less substituted carbon), and X adds to the more substituted carbon, yielding the more stable carbocation intermediate.

• 19
  Front

  What is the mechanism of electrophilic addition of Br2 to an alkene?

  Back

  Br2 approaches the pi bond, forming a bromonium ion intermediate (cyclic, three-membered ring with Br+). Bromide then attacks the back of one carbon in an SN2-like step, giving anti addition (trans product).

• 20
  Front

  In IR spectroscopy, what wavenumber range indicates an O-H stretch of a carboxylic acid, and what is its characteristic appearance?

  Back

  O-H stretch of a carboxylic acid appears as a broad absorption from approximately 2500-3300 cm-1, due to strong hydrogen bonding.

• 21
  Front

  In IR spectroscopy, at approximately what wavenumber does a carbonyl (C=O) stretch appear, and why is it diagnostic?

  Back

  The carbonyl stretch appears near 1700-1750 cm-1. It is strong and easily identified, making it a reliable diagnostic peak for ketones, aldehydes, and carboxylic acids.

• 22
  Front

  What does chemical shift (delta, in ppm) measure in 1H NMR spectroscopy?

  Back

  Chemical shift measures the resonance frequency of a proton relative to TMS (tetramethylsilane, set at 0 ppm). It reflects the electronic environment of the proton; deshielded protons appear at higher ppm values.

• 23
  Front

  What is the n+1 rule in 1H NMR spectroscopy?

  Back

  A proton (or set of equivalent protons) with n adjacent non-equivalent protons will be split into n+1 peaks (a multiplet), due to spin-spin coupling.

• 24
  Front

  What information does the integration of an NMR signal provide?

  Back

  Integration gives the relative number of protons responsible for each signal. The ratio of integrated areas corresponds to the ratio of the number of equivalent protons in each environment.