BIOC 107 UNC MIDTERM EXAM 2025

Acid - -proton donor Base - -proton acceptor Conjugate acid/base pair - -the dissociated acid + the base that results from the dissociation [H+] - --actually H3O+ -moles/liter -measure of acidity [H+][OH-] for Water - -1x10^-14 at standard temperature pH - --log[H+] [H+] - -10^-pH pOH - --log[OH-] [OH-] - -10^-pOH pH + pOH for Water - -14 (at standard temp) pH = pOH when? - -in pure water 2H2O= H3O+ + OH- HA <--> H+ + A- - -Ka= ([H+][A-])/[HA] pH= pKa + log([A-]/[HA]) Strong Acid - --dissociates essentially 100% -large Ka (ex. HNO3 = 20) -small pKa (ex. HNO3 = -1.3) -weak conjugate base Weak Acid/weak base - --dissociates very little -small Ka (1.3 x 10^-4) -large pKa (ex. C2H4OHCOOH= 3.9) -strong conjugate base Strong Base - -Ka of PO43- is 2.2x10^-13 BIOC 107 UNC BIOC 107 UNC BIOC 107 UNC pKa= 12.7 Group 1 and 2 metals Buffers - --Solutions that resist changes in pH when small amounts of acid or base are added -a solution of a weak acid and its conjugate base (salt) or a solution of a weak base and its conjugate acid. At what pH does a buffer function most effectively? - -when the amounts of acid and conjugate base are approximately equal. Buffer Range - -The buffering region is about 1 pH unit on either side of the pKa of the conjugate acid. conjugate base - -The species that is created after the donation of a proton. conjugate acid - -The species created when a base accepts a proton. conjugate acid-base pair - -Two molecular entities differing only by a single proton. Henderson-Hasselbalch Equation - -pH=pKa+log([base]/[acid]) allows you to calculate the relative amounts of HA and A- at any point along the curve Titration Curve - - Neutralization Reactions - -Produce water as a product. If product is only water, then the reaction was FULLY neutralized. (H+ and OH-) **KNOW HOW TO WRITE AND BALANCE NEUTRALIZATION EQUATIONS GIVEN THE ACID AND BASE COMPONENTS** - - 1) Molecules being made (products) 2) Charge 3) Balance 4) Ionize 5) Redundancy be able to derive net ionic equations - -~shrrugs~ Organic Compounds - -molecules composed of carbon nature of C-C vs C=C and C(triple bond)C - -C-C: saturated C=C: unsaturated C(triple):unsaturated 1 C - -meth- BIOC 107 UNC BIOC 107 UNC 2 C - -Eth- 3 C - -Prop- 4 C - -But- 5 C - -Pent- 6 C - -Hex- 7 C - -Hept- 8 C - -Oct- 9 C - -Non- Reactions of Alkenes usually involve... - -the addition of 2 atoms or groups to the C=C double bond Markovnikov's Rule - --hydrogen will go to Carbon with more Hydrogens connected to it; friends -used to predict products from asymmetric addition Rx to alkenes. - "when an unsymmetrical reactant of the type H-X (ex. H-OH) adds to an unsymmetrical alkene, the carbon with the greater number of hydrogen atoms gets one more hydrogen." **Know names of functional groups** - -I have a separate set of cards for this Aromatic Compounds - --based on planar molecule benzene, C6H6 -The electrons in the Carbon-Carbon bonds do not exist as they do