Acid-Base

Review of naming acids

Determine Name:
H
2
SO
3
H
2
SO
4
H
2
S
HClO
3
HCl
HClO
2

Determine Name:
H
2
SO
3
H
2
SO
4
H
2
S
HClO
3
HCl
HClO
2

Determine Formula
Hydrofluoric acid
Carbonic acid
Nitrous acid
Hydroselenic acid

Determine Formula
Hydrofluoric acid
HF
Carbonic acid
Nitrous acid
Hydroselenic acid

Characteristics of Acids & Bases

Acids are Characterized by:
O
O
Sour taste
 color of indicator
O
O
Release of H
2 gas
Reacts with bases  salt( ionic compound) & H
2
O

Bases are Characterized by:
O Bitter taste
O
O
Feels slippery
 color of indicator
O
O
Reacts with acid  salt( ionic compound) & H
2
O
Conducts electric current ( its an ionic compound)

What does ionization mean?

Ionization
O Adding or removing electrons (e-)
O Making a cation or anion

Strong Acids
O Ionizes completely = breaks up completely
O Conducts electric current
(remember electrolyte demo & PhET)

Strong Acids
Examples:
O Hydrochloric Acid (HCl)
O Sulfuric Acid (H
2
SO
4
)
O Nitric Acid (HNO
3
)

Strong Base
O Ionizes completely = breaks up completely
O Examples: group 1 hydroxides – sodium hydroxide, potassium hydroxide, etc.

Neutralization Reaction
HCl + NaOH  NaCl + HOH
Strong + Strong  Salt + Water
Acid Base
HNO
3
+ KOH  KNO
3
+ HOH

Neutralization Reaction
Is a double replacement rxn b/w … strong acid + strong base  a salt (ionic compound) + water

pH Scale
Determining strength of an Acid or Base

pH scale 0-14
O neutral pH = 7.0
O acidic pH <7.0
O basic pH > 7.0

pH Scale

Calculating pH & [H + ] pH = -log[H + ]
Inverse of log
10 is 10 ^( )
[H + ] = 10 ^(-pH)

Calculating pOH & [OH ] pH = -log[OH ]
Inverse of log
10 is 10 ^( )
[OH ] = 10 ^(-pOH)

Relationship between pH & pOH pH + pOH = 14

Now you try…

Answer

Try on your own…

Try on your own…

Practice

Now you try

Answer

Try on your own..

Answers

Other methods of determining pH

If molarity is not known, pH can be determined by…
O Acid-Base Indicators
O pH meter
O Titration

Indicator Solutions
O Change color depending on pH of test solution

Indicators

Indicators

Indicators

Problems with indicator solutions:
O If you have a colored solution
O Approx pH value not exact
O Temperature affects color 

pH meter

pH meter
O consists of a measuring probe
O electronic meter: measures & displays the pH reading
O have to calibrate probe

Titration
O Use Buret, Erlenmeyer flask, indicator
O Use M
1
V
1
= M
2
V
2 to determine molarity of unknown

Titration

Titration

Answer the following questions while watching the video clips:
1.
Where do you read/How do you read a burette?
2.
3.
What hand do you use to swirl the Erlenmeyer flask?
What hand do use to adjust the burette?
4.
5.
6.
When do you know you are getting close to the endpoint?
How is the standard solution added as you get close to the endpoint?
When do you know you have achieved the endpoint?

O Titration Video Clip #1 (3:15)
O Titration Video Clip # 2 ( 6:07)

Now, do the titration pre-lab