warm-up
DESCRIPTION
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. Write formulas for the following acids: - PowerPoint PPT PresentationTRANSCRIPT
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!
EXAMPLECalculate the pOH for a solution of
NaOH with a concentration of 1 x 10-4 M.
pOH = -log[OH-]pOH = 4
EXAMPLECalculate the pOH for a solution of
KOH with a concentration of 0.01 M.
pOH = -log[OH-]pOH = 2
EXAMPLEWhat 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-UPWhat’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 INDICATORSAcids and BasesWhitaker18 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= M2V2Where 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
EXAMPLEIf 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
EXAMPLEIf 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 MATHWhen doing titrations, you must account for di- or triprotic acids by adding a 2 or 3 to the acid side.
EXAMPLEIf 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?