pH, pOH calculationsTitration Calculations

Chemistry5/29/15

Drill

Drano is mainly sodium hydroxide. The [OH-] is often around 0.35 M.

Calculate the pH, pOH, and [H+]

HW: Finish Acids and Bases Review #35-37 (I’ll check the whole thing on Monday)

Objectives

IWBAT:Calculate the pH and pOH of a solution using pH scale calculations

Calculate the concentration of an unknown acid by using titration

NOTES:• Titration Lab–6/2 & 6/3—Tuesday and

Wednesday – CLOSED TOE SHOES• Acids & Bases Test – Friday 6/5

Titration Notes/Demo

Titration

An acid-base titration is a carefully controlled neutralization reaction:• Acid + Base Salt + Water• ex. HCl (aq) + NaOH (aq) NaCl (aq) + H2O(l)

The point of titration is to determine the concentration of an unknown acid or base, using a standard solution that has a known concentration.

Goal of Titration

Procedure used to determine the concentration of an unknown acid or base

Standard solution – solution with the known concentration

More about Titration

The equivalence point is when all of the acid and base have neutralized each other.

The end point is when the indicator changes color.

They should be close together – Why? Some indicators change at high pH,

some at low pH.

Titration

We will be using phenolphthalein as our indicator.

What color is it? Ms. Bloedorn will

demonstrate.

http://img.sparknotes.com/figures/3/3a5994498f24d59f5d5d762b40844a2a/titsetup.gif

Equivalence Point

Use phenolphthalein as an indicator• Turns fuchsia in a basic solution• Stop titrating when the solution turns light

pink• This is called the endpoint

http://www.lakelandschools.us/lh/lburris/images/Titration.gif

Titration Calculations

Let’s go through Scenario #1 together. Do Scenario #2 on your own. Let’s review

Titration Practice Problems

Work on the Titration Problems Make sure to show the mole ratio step! I’ll circulate to help—check the answer

key as you go

Closure

What is the point of a titration?

What is the difference between “end point” and “equivalence point”?