SI Chem 231
Leader: Kelsey
Worksheet 1
Chapter 1
Review:
Fill in any unshared electrons that are missing from these structures:
Is this formula correct? Why/why not?
C2H7
Identify the most electronegative element in each of the following molecules:
CH2FCl
HOCH2CH2NH2
FCH2CH2CH2Br
CH3OCH2Li
Propose a structure that:
a) Contains 2 sp2 carbons and 2 sp3 carbons
b) Contains 4 carbons, all are sp2
c) Contains 2 sp carbons and 2 sp2 carbons
Define:
Bronsted-Lowry acid:
Bronsted-Lowry base:
Strong acid:
Lewis acid:
Lewis base:
The acidity constant, Ka, gives the exact strength of a given acid HA in a water
solution.
HA + H20  A- + H30+
Ka= [H30+] [A-]
[HA]
How would you write the Ka for:
HCl + H20  H3O+ + ClKa=
Acid strengths are normally given using pKa values, rather than Ka values:
pKa=
Circle one:
A stronger acid has a (smaller/larger) pKa and a (smaller/larger) Ka.
A weaker acid has a (smaller/larger) pKa and a (smaller/larger) Ka.
Fill in the blank:
A strong acid yields a
A weak acid yields a
Which acid is stronger in each pair?
H3PO4
Phosphoric Acid
pKa= 2.16
HCl
Hydrochloric Acid
pKa=-7.0
H2O
HCCH
Water
pKa=15.74
HNO3
Nitric Acid
pKa=-1.3
Acetylene
pKa=25
CH3CO2H
Acetic Acid
pKa=4.76
Using curved arrows, show how acetaldehyde, CH3CHO, can act as a Lewis base in a
reaction with a strong acid, H+.