Exercise 2 Buffers and Amino acids
1. Carbonic acid (H2CO3) is a weak acid. Its dissociation constants are pKa1
= 6.35 and pKa2 = 10.3. Draw a schematic titration curve (H+ ions
dissociated per molecule along the x-axis, pH along the y-a
CHEM 255 STUDY GUIDE for EXAM #1
Exam#1: Thursday, Oct 27
Structure of the exam. The exam is in 2 sections. Section #1 is to be taken during class time
on Thursday and will be closed books and closed note. This section is worth 75 points. The
Section #2 w
Sample exam 1 B
1. (apts) Consider the polypeptide with the sequence Phe-Ser-Glu-LysHis-GluGlu.
Howmany peptide bonds (amide bonds) does this peptide have?
b. (2 pt) Would this peptide strand most likely be 1n the core /1nter1or or exterlor
ff.t nC. h Hlal
+) d J, nJ.-L.rf.
Cov-ho;.(1 h c
-:) 6. 0\ '?6
-c' -; -ti
- ,._ ' c.= 0
,J /c. "o-W
_,c -o _. R.
Am in.( :c_.J
_ _,.,._, lh ;
Secondary Structures _,.
H~hJ. s v,i>~Afpd
t'r J-~e:h ~
Cof\N. e.~ \l.ll
-rr 'rLt- *e.\Jx
Rotation about the a carbon
Acute Aspirin Overdose: Relationship to the Blood Buffering System
Acetylsalicylic acid (aspirin)
2. These questions can be answered by using the Henderson-Hassel
Chemistry 255 Name(s): iokn Eroahg) 30% K013?
Exercise 1 Buffers and Amino acids
1. Carbonic acid (H2003) is a weak acid. Its dissociation constantsare pKa1 = 6.35 and
pKa2 = 10.3. Draw a schematic titration curve (H+ ions dissociated per molecule alo
Exercise 1 Thermodynamic Analysis of Reactions
Some bond dissociation energies (bond strength) : Pi bond = 259 kJ/mole, H-H bond 436 kJ/mole,
C-H bond 410 kJ/mole
1a. What bonds were broken in this reaction?
b. What bond
Sample exam 1- section 1
Multiple choice :
1. If the enthalpy change for a reaction under standard conditions is zero, G is equal
c. +RT ln Keq
d. + TS
e. none of these
2. In the figure below, part of a polypeptide sequence is