warm-up

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?