Download Chemistry 160 Homework 1

Chemistry 160 Homework 1
1. Give 4 major types of biomolecules.
2. Why do we study structure?
3. For each of the following, indicate the types of intermolecular forces.
a. CCl4
b. H2O
c. CH3OCH3 d. Br2
4. Describe Hydrogen bonds. Give an example.
5. What is the velcro effect?
6. Using a diagram, show how sodium chloride dissolves in water.
7. Define amphipathic. Give an example of an amphipathic molecule.
8. Diagram and explain how soaps work.
9. Define chemical equilibrium.
10. Write equilibrium constant expressions for each of the following:
a. SO2(g) + H2O(l) <==> H2SO3(aq)
b. Ca(OH)2(s) <==> Ca2+(aq) + 2OH-(aq)
c. HCH2O(aq) + H2O(l) <==> H3O+(aq) + CH2O-(aq)
11. In mammals, an endproduct of anaerobic metabolism is pyruvate. If the system continues to
be anaerobic, pyruvate can be reduced to lactate by the equilibrium shown below:
Pyruvate + NADH + H+ => lactate + NAD+
Which way will the system shift under the following conditions:
a. Pyruvate is added.
b. In the presence of oxygen, pyruvate is used by another reaction so which will the
equilibrium above shift in the presence of oxygen?
c. NADH is added.
d. NAD+ is added.
e. Lactate is used.
12. Define acid and base.
13. What is the difference between a strong acid and a weak acid.
14. For the following 4 acids give the conjugate base.
a. HCOOH, pKa = 3.20
b. CH3COOH, pKa = 4.74
c. CH3CH2COOH, pKa = 4.9
d. CH3CH(OH)COOH, pKa = 3.8
15. Rank those same acids in order from lowest to highest strength.
16. Use a buffer made from ammonia and ammonium ion to illustrate how a buffer can neutralize
both added acid and added base.
17. Draw a titration curve for a generic weak diprotic acid H2A with pKa1 = 3.63 and pK a2 =
8.64 and do the following:
a. Label the axes.
b. Show both equivalence points.
c. Show, on the graph where the pK's are.
d. Indicate in which regions each of the following is the dominant species.
ii. HA-
i. H2A
iii. A2-
18. Define oxidation and reduction.
19. For each of the following, indicate which reactant is being oxidized and which is being
reduced.
O
C
H
C
H
OH
CH2OP
a.
O
O
+
O P
O
O
+
C
OP
NAD+
H
C
OH
CH2OP
+
NADH
+
+
H
19b.
OH
R
CH2
CH
CH2
C
O
O
O
S-CoA
+
NAD+
R
CH2
C
20. Draw the following three reaction coordinates. Be sure to label the axes.
a. Spontaneous with activation energy
b. Spontaneous without activation energy
c. Nonspontaneous.
21. What is entropy and how is it used to drive a reaction?
22. Describe reaction coupling. Give an example.
Book Problems:
Pp. 35 - 36: 35, 37, 38, 42, 51, 52
Pp. 62 - 64: 1, 5, 7, 10, 11, 13, 52
CH2
C
S-CoA
+
NADH
+ H+