Download CHEM 2411 – Organic Chemistry I Chapter 2: Additional Problems 1

CHEM 2411 – Organic Chemistry I
Chapter 2: Additional Problems
1) Rank the following compounds in order of increasing acidity (i.e., x < y < z)
a
b
Cl
O
Cl O
O
F
H
c
Br
O H
Br
d
O
Cl
O H
O
F
O H
F
c<b<d<a
2) A 250.0 mM aqueous solution of an acid HA has a pH of 5.2. What is the pKa of HA?
If pH = 5.2, and pH = -log [H3O+], then [H3O+] = 10-5.2 = 6.3 × 10-6, and [A-] = 6.3 × 10-6
Now determine Ka based on the equation
Then pKa = -log Ka = 9.8
3) Provide the skeletal structures for the following:
a) (CH3CH2)3N
N
b) CH3CH(OH)CH(OH)CH(OH)CH3
OH OH
OH
4) What kind on molecular orbital (σ, σ*, π, or π*) results when the two atomic orbitals shown
below interact in the manner indicated?
Answer: π
5) The atomic number of boron is 5. The correct electronic configuration of boron is:
A) 1s22s3
B) 1s22p3
C) 1s22s22p1
D) 2s22p3
E) 1s22s23s1
Answer: C
6) Draw a correct Lewis structure for boric acid, B(OH)3.
Answer:
or
7) In the structure below, the sigma bond of the carbonyl is formed from the overlap of a(n)
________ atomic orbital of carbon and a(n) ________ atomic orbital of oxygen.
A) sp, sp2
B) sp3, sp2
C) sp2, sp2
D) p, p
Answer: C
8) Complete the structure of methyl azide by adding any necessary formal charges.
Answer:
9) Which of the following condensed formulas represents the same compound as the line-angle
structure shown?
A) CH3CH2CH2OCH2CH2CH2N(CH2CH2CH3)2
B) CH3CH2CH2OCH2N(CH2CH3)2
C) CH3CH2OCH2N(CH2CH3)2
D) CH3CH2OCH2N(CH2CH2CH3)2
E) CH3ON(CH3)2
Answer: C
10) Calculate the empirical and molecular formulas of the compound with molecular weight
122 and an elemental analysis of 59.01% C, 4.97% H, 13.12% O, and 22.90% N.
Answer: Empirical and molecular formulas are the same: C6H6N2O.