Organic Chemistry Test Questions – Flashcards
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| AMINO ACID |
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| EQUIVALENT POINT |
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| Equimolar Mole [OH-] added = Mole [H+] present |
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| HALF EQUIVALENT POINT |
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| pH = pKa |
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| TITRATION OF AMINO ACID |
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| 1. COOH deprotonated before NH3 2. 2 moles of base for 1 mole of a.a 3. Buffer capacity is greatest at pKa1 and pKa2 but smallest at pI 4. pH of equivalent point is not usually 7 5. Indicator (weak acid-not involved in rxn) - best when closest to equi. pH HA(color 1) + H2O -> H3O + A- (color 2) * if [H3O] > Ka, sln will be color 1 |
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| HENDERSON- HASSELBALCH EQUATION |
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| pH = pKa - log [con. BASE]/ [con. ACID] |
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| NEUTRALIZATION |
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| EXOthermic rxn -> formation of something stable Always give Salt and WaterpH DOES NOT equal to 7 Depends on the acidity/basicity of the salt |
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| BUFFER |
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| NON-POLAR AMINO ACID |
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R = CHO, Hydrophobic,↓solubilty, INSIDE or at core of proteins or transmembrane to avoid H2O Alanine, Valine, Leucine, Isoleucine, Proline, Phenyl alanine, Glycine, Thryptophan |
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| POLAR AMINO ACID |
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R= Polar, Uncharged HydroPHILIC, ↑ solubility, on SURFACE of protein Methioninine, Serine, Theroine, Cystein, Tyrosine, Asparagine, Glutamine |
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| ACIDIC AMINO ACID |
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| R = COOH group - at Physiological pH = 7.4Have 3 distinct pKa's - 3 mole of base is needed for neutralization Important in substrate binding sites of enzymes |
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| BASIC AMINO ACID |
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| R= NH2 + at physiological pH = 7.43 moles of acid is needed to neutralize 1 mole of baseArginine, Lyscine, Histidine |
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| PEPTIDE |
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| Amino Acid subunitsPeptide bond= Amide bond formed via condensation (water is loss)Rotation about the C-N bond is limited because resonance give C-N a partial double bond character |
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| PROTEIN |
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| 1° = sequence of a.a2° = local structure of neighboring a.a due to H-bondingα helix (keratin) β pleated sheet3°= 3D shape of protein due to hydrophilic/Hydrophobic interaction between R groups of a.a Disulfide bond → loops in protein chain Proline can't fit into α helix → kink in chain Fibrous = sheets/long strands (collagen) Globulous = spherical (myoglobin> 4° = Arrangement of polypeptide subunit (Hemoglobin = 4 subunits) |
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| CONJUGATED PROTEINS |
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| Attached to prosthetic group (organic molecules or metal) |
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| DENATURIZATION |
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| Loss of 3D (3° structure → random coil state- disruption of INTERmolecular forces) Due to detergent, change in pH, Temp, [solute] Some protein can REnature |
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| EPIMERS |
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| Different in configuration at ONLY ONE carbon |
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| ANOMERS |
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| Differ in conjugation ONLY at the newly formed chiral center |
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| KETOSE |
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| Fructose |
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| ALDOSE |
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| Glucose Galactose Manose |
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| MUTAROTATION |
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| Allow α → α + β or β → α + β |
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| GLYCOSIDIC REACTIONS |
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| [image]Hemiacetal + Alcohol → Acetal Both α and β linkages are formed |
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| DISACCHARIDES |
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| Due to glycosidic linkages between C1-C4, C1-C6 or C1-C2 α or β In body, enzymes ar eneeded to ensure the right glysidic bond is form. Without enzymes, reactions are NONspecific and never stopping at disaccharide level |
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| GLUCOSE POLYSACCHARIDES |
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| Cellulose = β 1,4 Structure components of PLANT Starch = α 1,4(some 1,6) Stored energy in PLANT Glycogen= α 1,4 (some 1,6) Stored energy in ANIMAL * Cellulose can't be ingested by human |
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| IR |
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| Measure vibrations- Stretching, bending and rotation of a molecule- Stretching and bending can be Symmetric or AsymmetricLight → excited state (3500-300 cm-1 |
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| FINGER PRINT |
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| 400-1500 cm-1Characteristic of a molecule, frequently used to identify a substance |
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| SYMMETRIC STRETCH |
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| DO NOT show in IR because no net change in dipole moment |
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| IR ALKANES |
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| C-H 2800-3000 C-H 1200 |
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| IR ALKENES |
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| =C-H 3080-3140 C=C 1645 |
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| IR ALKYNES |
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| C ≡ C 2200 ≡ C-H 3300 |
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| IR Aromatic |
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| C-H 2900-3100 C-C 1475-1625 |
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| IR ALCOHOL |
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| O-H (broad) 3100-3500 |
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| IR ETHER |
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| C-O 1050-1150 |
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| IR ALDEHYDE |
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| (0)C-H 2700-2900 C=O 1725-1750 |
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| IR ACIDS |
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| C=O 1700-1750 O-H (broad) 2900-3300 |
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| IR KETONES |
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| C=0(Sharp) 1700-1750 |
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| IR AMINES |
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| N-H (Sharp) 3100-3500 |
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| C-NMR |
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| Larger sample NO coupling except between carbons and hydrogens directly attached to them Spin decoupling: record without coupling of adjacent protons Show: # of C's with relative chemical environment # of H's (spin coupling NMR's) |
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| UV |
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| Pass light, observe Absorbance Beer Law A= ebc Most useful for studying compound wit double bonds and heteroatoms with lone pairs |
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| MASS SPECTROSCOPY |
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| Pass light, measure mass of particle Sample is ruined afterward 1. cation radical decompose → mass/charge ratio 2. base peak = tallest peak (% of 100) 3. Molecular ion peak = highest m/e peak |
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| CARBOXYLIC ACID |
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| - suffix - ate1. Polar2. Able to form H-bond3. Greater bp than alcohol4. Acidity is due to resonance stabilization of conjugate base 5. β H's are extremely acidic because its loss → stable carbanion6. Acidity can be enhanced by adding EN gr. or other potential resonance structre |
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| NITRILES |
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| aka CYANIDEhas CN- group = good [NUC-] for 1°, 2° SN2 reactions |
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| SYNTHESIS OF CARBOXYLIC ACID |
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| 1. Oxidation of alcohol (using KMNO4)2. Ginard reagents (1 additional C)3° alkyl halide → carboxylic acid3. Hydrolysis of nitriles (1 additional C)CH3Cl → CH3CN→ CH3COOH + NH4- |
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| SOAP FORMATION |
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| RCOOH + NaOH → ROO-Na+ (soap) + H2OSoap tends to rearrange into micelles (like mb) with polar head outward and nonpolar tails inward to dissolve greaseMicelle (as a whole) is soluable in water because of polar shell |
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| ORDER OF REACTIVITY |
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| Acyl halide > anhydrides> Esters> Amindes |
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| ANHYDRIDES |
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| = without water 2 ACID → condensation→ Anhydrides |
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| AMIDES |
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| [image]Form from 1° or 2° amine |
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| HOFFMANN REARRANGEMENT |
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| Amides → 1° with loss of carbon[image] |
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| ESTERS |
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| ACID + ALCOHOL → ESTER[image] |
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| SAPONIFICATION |
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| Fats( triacylglycerols) are hydrolyzed under basic condition |
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| AMINES[image] |
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| prefix amino-Boiling point is lower than alcohol because N has lower EN3° amine can't H-bond thus have lower bp than 1° and 2°sp3 - able to undergoes nitrogen inversion (low Ea - 6 kcal/mol)* optically active if inversion is hinderedWeak Acid |
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| DRUGS WITH AMINES GROUP |
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| Nitroglycerine relaxants: relieve coronary arteries spasms for chest pain Nitrous oxide relaxants : dental anesthetic |
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| GABRIEL SYNTHESIS |
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| Primary Akyl halide → 1° amine (no side products)[image] |
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| EXHAUSTIVE METHYLATION |
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| aka Hoffmann Elimination [image] |
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| MICHAEL ADDITION |
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| [image] |
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| ALDOL CONDENSATION |
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| STRUCTURAL ISOMERS |
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| Most Different Different in MOLECULAR FOMRMULA |
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| CHIRALITY |
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| Chiral = nonsuperimposable Achiral - super imposable *rotation doesn't change chirality Differences in chirality can produce enantiomers (nonsuperimposed mirror images) or diastereomers ( diff, in chirality but not mirror images) |
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| GEOMETRY ISOMERS |
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| Different around DOUBLE BOND cis vs. trans Different in physicial properties (mp or bp) Similar Reactivity |
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| ENANTIOMERS |
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| Chiral moleculesIdentical properties but different in optical activity |
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| MESO COMPOUND |
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| Chiral but not optical active because of internal plane of symmetry |
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| OPTICAL ACTIVITY |
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| Ability to rotate plane in polarized light + dextrorotary - R - Levorotary - L α (angle of rotation) - observed oration/ [] g/ml x leight dm |
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| RACEMIC MIXTURE |
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| Mixture of equal concentration of + and = enantiomers |
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| DIASTERIOMERS |
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| 2+ chiral centers Different in chirality but not mirror images R,S vs. R,R |
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| CONFORMATION ISOMERS |
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| Different ONLY by rotation about 1 or more single bond"gauche" vs " eclipse" |
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| ALKANES |
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| ↑ chain length → ↑ bp, mp , density → ↓ bp, mp, density Stablity of carbocation and free radical 3° > 2° > 1° > methyl |
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| PYROLYSIS |
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| Molecules is broken down by heat aka: craking → radicals |
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| NUCLEOPHILES |
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| 1. Basicity RO-> HO->RCO2-> ROH> H2O 2. Size and Polarity - Protic solution (able to H-bonding) CN-> I-> RO-> HO-> Br-> Cl-> F-> H2O - Aprotic solution F-> Cl> Br> I 3. Larger atom = better Nuc |
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| LEAVING GROUP |
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| Weak acid = best I> Br > Cl > F |
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| SN1 |
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| Rate is dependant on the formation of carbocationCondition is chosen so that the second step is IRREVERSIBLErate = k[S] |
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| ACCELERATE FORMATION OF CARBOCATION |
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| 1. Structural factors: more subs → more stable carbocation → better SN12. Solvent effect: Polar Solvent (better at surrounding and isolating ions) Protic polar is best (solvation stabilize intermediate)3. LG : weak bases dissociate more easily |
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| INTERMEDIATE |
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| Well defined species with a finite lifetime |
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| TRANSITION STATE |
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| Theoretical structure used to define mechanism |
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| SN1 vs SN2 |
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| SN1 2 steps Favored : polar PROTIC solvent 3>2>1 racemic products (loss of optical activity) Favored the use of bulky [Nuc] SN2 1 step - concerted Favor: polar APROTIC solvent 1>2>3 rate = k[RX][Nuc] Optically active / inverted products |
