Catalyst: Tuesday February 4, 2014
Today’s Objective: -SWBAT use Ka/Kb to predict the strengths of acids and bases
-SWBAT solve problems using Ka and Kb
Log into ExitTicket and complete the launch
Photo of the day
Ion Product Example
Complete on doc cam
Weak Acid (Using Ka)
Complete on doc cam
Table Talk
• You have a solution of the following acid:HOC6H5 (aq) + H2O (l) H3O+ (aq) + OC6H5
- (aq)• Given that the equilibrium concentrations are
[HOC6H5] = 0.062 M, [H3O+ ] = 1.5 x 10-4 M, and [OC6H5
- ] = 3.1 x 10-5 M, calculate the value of Ka.
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Model
• Calculate the pH of a 0.036 M Nitric Acid (HNO3) solution
HNO3 D H+ + NO3-
Discussion Question
• Calculate the pH of a 0.036 M Sodium Hydroxide solution
NaOH D OH- + Na+
Quicket
Using the table below, which compound would you expect to be the strongest acid?
AB
C
D
Quicket
Using the table below, which compound would you expect to be the strongest acid?
Compound Kb Value
A) Phosphate 5.9 x 10-3
B) Carbonate 2.1 x 10-4
C) Ammonia 1.8 x 10-5
D) Aniline 9.5 x 10-7
Table Talk
• Calculate the Ka for the ammonium ion (Kb = 1.8 x 10-5)
Table Talk
• Consider the following two acids and their ionization constants:
HCOOH Ka = 1.7 x 10-4
HCN Ka = 4.9 x 10-10
Which conjugate base (HCOO- or CN-) is stronger?
