WARM-UP What is the pH of a 0.00078 M solution
of HI?
What is the pOH of a 0.045 M solution of NaOH?
What is the [H+] concentration of a solution of HBr that has a pH of 5.6?
What is the pH of a 0.56 M solution of KOH?
WARM-UPWrite formulas for the following acids:Hydroiodic AcidCarbonic AcidHydrosulfuric AcidNitrous acid
POH ANDTITRATIONSAcids and Bases, Day 3Whitaker17 December 2013
POH
Same as pH, but opposite. Goes from 0 -14 0 - 6.99 is basic 14 – 7.01 is acidic pOH = -log[OH-] [OH-]=10-pOH
REMEMBER!!The molarity of an acid is the Hydrogen (or Hydronium) ion concentration!
The molarity of a base is the Hydroxide ion concentration!
EXAMPLE
Calculate the pOH for a solution of NaOH with a concentration of 1 x 10-4 M.
pOH = -log[OH-]pOH = 4
EXAMPLE
Calculate the pOH for a solution of KOH with a concentration of 0.01 M.
pOH = -log[OH-]pOH = 2
EXAMPLE
What is the concentration of a basic solution that has a pOH of 13?
[OH-] = 10-pOH
[OH-] = 1 x 10 -13 M
PH AND POH
As the concentration of [H+] or [OH-] goes up, the other must go down.pH + pOH = 14
EXAMPLE
What is the pH of a solution that is found to have a pOH of 10?
pH = 4
EXAMPLE
What is the pH of a 0.001 M solution of LiOH?
pOH = 3pH = 11
EXAMPLE
What is the pOH of a 0.0001 M solution of HCl?
pH = 4pOH = 10
What is the pH of a solution HI with a concentration of .001 M?
What is the concentration of a strong acid with a pH of 3?
What is the pH of a solution of a NaOH with a concentration of 1.0 x 10-6 M?
OBJECTIVES
Define aspects of a titration. Calculate the molarity of a solution using
titrations.
WARM-UP What is the pH of a 0.00078 M solution
of HI?
What is the pOH of a 0.045 M solution of NaOH?
What is the [H+] concentration of a solution of HBr that has a pH of 5.6?
What is the pH of a 0.56 M solution of KOH?
WARM-UP
What’s the pH of a 0.0001 M solution of NaOH?
What’s the molarity of HCl if the pOH is 13?
If it takes 55 mL of 0.001 M HCl to neutralize 122 mL of a NaOH solution, what is the concentration of the NaOH solution?
TITRATIONS AND INDICATORS
Acids and Bases
Whitaker
18 December 2013
TITRATIONS
A titration is a way of determining the molarity of an unknown solution by adding small volumes of a solution with a known molarity.
Involve neutralization reactions.
NEUTRALIZATION REACTION
Remember that when an acid and base mix, a salt and water are always produced!
Example: NaOH + HCl -> NaCl + H2O
KOH + HI -> KI + H2O
H2SO4 + 2 LiOH -> Li2SO4 + 2 H2O
VOCABULARY OF TITRATIONS
The equivalence point - point where exactly enough titrant has been added to react with all of the analyte.
Indicator - a compound that changes color at certain pH’s.
PARTS OF THE BURETTE
Acid or base and indicator
Buret containing base or acid
Stop-cock
Flask
Buret clamp
A LITTLE MORE MATH!!! In titrations we are looking for the
concentration (Molarity) of an unknown solution.
M1V1= M2V2
Where M1 is the molarity of the acid V1 is the volume of the acidM2 is the molarity of the baseV2 is the volume of the base
EXAMPLE
If it takes 54 mL of 0.1 M NaOH to neutralize 125 mL of an HCl solution, what is the concentration of the HCl?
.0432 M
EXAMPLE
If it takes 25 mL of 0.05 M HCl to neutralize 345 mL of NaOH solution, what is the concentration of the NaOH solution?
.0036 M
INDICATORS!!!Indicator Acid Transition Color Base
Phenolphthalein Clear Lt Pink (8.2-10.6) Hot pink
Methyl Red Red Buff (4.8-6.0) Yellow
Methyl Yellow Red Orange (2.9-4.0) Yellow
Litmus Pink Mauve (5.5-8.0) Blue
Bromthymol Blue Yellow Green (6.0-7.6) Blue
REVIEW
[H30] = [??]How do acids and bases taste?What is a strong acid?What does alkaline mean?What is the “most basic” pH??Under what conditions do gases
best dissolve?
DIFFERENT TYPES OF ACIDS
MonoproticContains one HydrogenHCl
DiproticContains two HydrogensH2SO4
TriproticContains 3 HydrogensH3PO4
CHANGES TO MATH
When doing titrations, you must account for di- or triprotic acids by adding a 2 or 3 to the acid side.
EXAMPLE
If it takes 50 mL of 0.5 M KOH solution to completely neutralize 125 mL of sulfuric acid solution (H2SO4), what is the concentration of the H2SO4 solution?