pKas – Chemistry – Flashcards
Unlock all answers in this set
Unlock answersquestion
Hydrobromic Acid |
answer
HBr -9 |
question
Hydrochloric Acid |
answer
HCl -8 |
question
Picric Acid |
answer
(NO2)3C6H2OH 0 |
question
Hydrofluoric Acid |
answer
HF 3.2 |
question
Acetic Acid |
answer
HCO2CH3 4.75 |
question
Benzoic Acid |
answer
PhCo2H 4.25 |
question
Hydrazoic Acid |
answer
HN3 4.7 |
question
Cyanic Acid |
answer
HCN 9.1 |
question
Thiophenol |
answer
PhSH 6.5 |
question
Ammonium |
answer
NH4+ 9.2 |
question
Phenol |
answer
PhOH 10.0 |
question
trifluoroethanol |
answer
F3CCh2OH 12.4 |
question
Amide |
answer
Ch3CoNH2 15.1 |
question
methanol |
answer
15.5 |
question
water |
answer
H20 15.75 |
question
Alkane Chain Length |
answer
Decreases acidity in solution (makes it harder to solvate) |
question
Electrowithdrawing group |
answer
Increase Acidity by stabilizing the anion |
question
Ketones |
answer
20 |
question
thiols |
answer
about 10 |
question
esters, nitriles, sulfones |
answer
~25 |
question
Alcohols |
answer
16-18 |
question
Adenine |
answer
[image] |
question
Thymine |
answer
[image] |
question
Guanine |
answer
[image] |
question
Cytosine |
answer
[image] |
question
Uracil |
answer
[image] |
question
Toluene |
answer
C6H5CH3 37 |
question
ethers |
answer
~20 |
question
E vs. Z acids |
answer
Acids prefer the Z-form by about 5 kcal/mol |
question
Carbocation Stability |
answer
More substituted carbons more stable cation because of electron donating methyls and hyperconjugation/resonance |
question
Carbanions |
answer
Stability affected by Electronegativity, delocatiolization of charge |
question
Activation Energy -> half life 3 5 10 15 20 30 |
answer
3->17E-12s 5->4.8E-10s 10->2E-6s 15->0.0084s 20->35s 30->6916 days |
question
Radicals |
answer
More substituted carbons also more stable radicals |
question
Equilibrium Constants and Free Energy Difference 0 -1.36 -2.72 -4.08 |
answer
0 -> K = 1 50% each -1.36 -> K = 10 90% 10% -2.72 -> K = 100 99% 1% -4.08 -> K = 1000 99.9% 0.1% |
question
Thorpe-Ingold Effect Gem-dimethyl Effect |
answer
Increasing size of substituents of tetrahedral center increases reaction rate between other two and decreases the angle |
question
Anomeric Effect |
answer
Explains why OCH3 prefers axial when in a heterocycle, and why hydrogen peroxide is at 120 |
question
Inductive Effect |
answer
Withdrawing Electrons through sigma bonds to the more electronegative group |
question
Field Effect |
answer
polarization through charges that interact through space |
question
Hybridization Formula |
answer
cos @ = -1/m sp^m |
question
Electronegativity |
answer
1/2(Ionization Potential + Electron Affinity) |
question
Hill Plot |
answer
log ([SL]/[S]) vs. log [L] expect 1 but if slope greater than one hints at cooperativity |
question
Benensi-Hildebrand Plot |
answer
Double Reciprocal 1/[Fraction of S] vs. 1/[L] |
question
Scatchard Plot |
answer
calculates affinity constant of ligand with protein |
question
R lnKa = (with heat capacity) |
answer
-dH/T + CplnT + (dS-dCp) |
question
dielectric constant |
answer
Measured by the shielding a solvent gives when put between a capacitor by opposing the E-field |
question
Kirkwood Factor |
answer
Related to the Bell Equation and Dielectric Constant e-1/2e+1 |
question
delta-d Solubility |
answer
Hildebrand "Cohesive Energy Density" d^2 = dH(vap) - RT/molar volume |
question
Kosover Z-Scale (Z) Reichardt Scale (Et) |
answer
From Absorption Spectra of salts The more polar the solvent the higher the frequency of light needed to go from ion pair to two radicals |
question
Y Scale |
answer
Winstein and Grunwald Used rates of solvolysis of t-Bu chloride log ky/k0 = mY m - substrate specificity Y = solvent scale and also related to Et k0 based off 80% aquaous ethanol (20% water) |
question
Why Water is weird |
answer
1) Temperature of max density higher than melting point 2)thermal expansion 1/V(dV/dT) is negative from -20 to 4 3) Bulk Modulus Kappa= -VdP/dV has minimum at 46 C 4)Cp pretty much constant from 0-100 but changes a lot at low temperatures |
question
18-crown-6 |
answer
K+ |
question
15-crown-5 |
answer
Na+ |
question
Crown Ethers and Macrocycles pioneered by: |
answer
Cram, Lehn, Petersen |
question
spherands |
answer
[image] |
question
Rebek |
answer
Kemp's Triacid to bind DNA bases |
question
Hamilton |
answer
Cyclophane like things to make bind adenine |
question
Zimmerman |
answer
Molecular Tweezers 3 aromatic portions with acid moeity to bind |
question
Secondary vs. Primary H-bonding |
answer
Primary worth 7.5 Secondary worth 2.5 |
question
Cyclophanes |
answer
Diederich evolved from Pedersens crown ethers Had solubilizing Ammonium Groups |
question
alpha-effect |
answer
larger anions not as well solvated, originally thought to be lone-pair lone-pair repulsions |
question
Hammett Equation |
answer
log Kx/Ko = sigmax * rho a positive sigma -> electron withdrawing negative -> electron donating ?>1, the reaction is more sensitive to substituents than benzoic acid and negative charge is built during the reaction. 0<?<1 , the reaction is less sensitive to substituents than benzoic acid and negative charge is built. ?=0, no sensitivity to substituents, and no charge is built. ?<0, the reaction builds positive charge. |
question
Swain-Scott Equation |
answer
log (k/ko) = sn n = nucleophilicity s = substrate specificity |
question
Grunwald-Winstein Equation |
answer
log(k/ko) = mY Y is solvent scale m is sensitivity of substrate based of solvolysis of t-butyl chloride in 80% aqueous ethanol |
question
alpha-carbonyl effect on Sn2 |
answer
has to be in the same plane with p orbital of carbonyl and siqma star LUMO |