Transcript Acid/Base Chemistry

Today…

Before Class:
 Grab a Lab Packet, Safety Goggles, and
Apron
 Our Plan:
 Inquiry Lab
 Wrap Up – Venn Diagram
 Homework (Write in Planner):
 Inquiry Lab Due next class
Quiz Make Up Tomorrow ELO
 Rocket Lab Make Up Thursday ELO

Today…



Turn in:
 Acid/Base Lab if haven’t yet
 Grab YOUR LAST Calendar, Booklet, & WS Packet
 You need a TEXTBOOK today!
Our Plan:
 New Calendar
 Notes
 Stop the Process/Activity
 Notes – pH
 Worksheet #1
Homework (Write in Planner):
 Worksheet #1 Due next class
Chemistry Humor….
Properties of Acids & Bases
ACIDS
Produce
H3O+1 ions
when
dissolved
in water
BASES
Produce
OH-1 ions
when
dissolved
in water
Properties of Acids & Bases
ACIDS
Taste
tart or
sour
BASES
Taste
Bitter
Properties of Acids & Bases
ACIDS
Corrosive
to body
tissue
BASES
Feel
Slippery
Properties of Acids & Bases
ACIDS
Turn
blue
litmus
red
BASES
Turn
red
litmus
blue
Properties of Acids & Bases
ACIDS
Metals react
with acids
to form
hydrogen
gas
BASES
Properties of Acids & Bases
ACIDS
BASES
Properties of Acids & Bases
ACIDS
BASES
Properties of Acids & Bases
ACIDS
BASES
Nomenclature of Acids
HCl
HF
HBr
HI
Hydrochloric
Acid
Hydrofluoric
Acid
Hydrobromic
Acid
Hydroiodic Acid
More Acids
HC2H3O2
H2SO4
HNO3
H2CO3
H3PO4
Acetic Acid
Sulfuric Acid
Nitric Acid
Carbonic Acid
Phosphoric Acid
Nomenclature of Bases
 Generally,
bases are metal
hydroxides, so name the metal +
hydroxide
 Examples:
– potassium hydroxide
 NaOH – sodium hydroxide
 LiOH – lithium hydroxide
 KOH
Real Life Acids
Vinegar
Aspirin
Vitamin
C (orange juice)
Soft Drinks (Coca Cola)
Foods – Citrus Fruits,
Tomatoes
Real Life Acids
Stomach
Acid (Bulimia)
Fertilizer
Car
Batteries
Acne Face Washes
Real Life Bases
Antacids
Deodorants
Plaster
Laxatives
Baking
Soda
Real Life Bases
Dish
Detergent
Body Wash (Soap)
Lye
Oven & Drain Cleaner
Bleach
STOP
Complete
the Stop the
Process Activity in your
notes.
Strong Acids/Bases
Fight Club Video
 http://www.youtube.com/watch?v=mg3m
8wRVXWg

Hydrogen Ions in Water
 Water
molecules, like anything,
are in constant, random motion
 Occasionally the collisions
between water molecules are
energetic enough to transfer a
hydrogen ion from one molecule
to another
Hydrogen Ions in Water
A
water molecule that loses a
hydrogen ion becomes a
negatively charged hydroxide ion
(OH-1)
 A water molecule that gains a
hydrogen ion becomes a
positively charged hydronium ion
(H3O+1)
Hydrogen Ions in Water
 The
reaction in which water
molecules produce ions is called
the self-ionization of water.
2H2O ↔ H3
+1
O
+
-1
OH
The Ionization of Water
 2H2O
↔ H3O+1 + OH-1
equilibrium, only 1.0 x 10-7 moles of
H3O+1 and OH-1 are formed (at room
temperature). So the concentrations of
H3O+1 and OH-1 in pure water are
1.0 x 10-7 M.
 At
The Ionization of Water
This
means the concentrations
of H3O+1 and OH-1 are equal in
pure water.
Any aqueous solution in which
[H3O+1] and [OH-1] are equal is
called a neutral solution.
The Ionization of Water
 In
any aqueous solution, the product
of hydronium ions and hydroxide
ions equals 1 x 10-14
[H3O+1] [OH-1] = Kw = 1 X 10-14
 Brackets indicate concentration
 Kw represents the ion-product
constant of water
Acidic & Basic Solutions
 Not
all solutions are neutral
 If the concentration of hydronium is
greater than hydroxide, the solution
is ACIDIC
 If the concentration of hydronium is
less than hydroxide, the solution is
BASIC (alkaline)
pH
concentrations of [H3O+1] &
[OH-1] can be very small, and
expressing concentration in molarity
can be a pain, so…
 Soren Sorensen came up with the
pH scale in 1909
 The pH scale is from 0-14, 0 being
very acidic and 14 being very basic
 The
pH
French
for pouvoir hydrogene,
which means “hydrogen
power”
Low pH = very acidic
High pH = very basic
7 = Neutral
Calculating pH
To turn such small concentrations into a
pH scale, it is necessary to use
logarithms
 Logarithms allow a large range of values
to be conveniently expressed as small,
nonexponential numbers.
 Do you remember logarithms from
math class?

Calculating pH
example, log 103 = 3 and log
106 = 6. Although there is a
range of three orders of
magnitude (10 x 10 x 10 or
1000) between the numbers 103
and 106, the range of the log
values is only 3!
 For
Calculating pH (strong acids)
To
calculate, use:
pH = -log[H3O+1]
[H3O+1] = hydronium
ion concentration
WHY?
This
is because strong
acids completely dissociate
This means that the
molarity of the acid IS THE
SAME AS the molarity of
+1
H3O
Neutral Water
For
this reason, neutral
water has a pH of 7!
-7
pH = -log[1 x 10 ]
pH = 7
 Try
typing it in your calculator
Try it Out!
Complete
the pH table in
your Note Booklet using
your calculator and the
formula.
The Answers
pH
10-pH
0
1
1
0.1
2
0.01
3
0.001
4
0.0001
The Answers
pH
10-pH
5
0.00001
6
0.000001
7
0.0000001
8
0.00000001
9
0.000000001
The Answers
pH
10-pH
10
1 x 10-10
11
1 x 10-11
12
1 x 10-12
13
1 x 10-13
14
1 x 10-14
pH
 The
numbers in the column
10-pH that you found are the
hydronium ion concentration
 To calculate [H3O+1] = 10-pH
pOH
 pOH
is the same as pH, but
instead of being a measure of
the hydronium ion concentration,
it is the measure of the
hydroxide ion concentration
 It is the exact opposite!
pOH
Low
pOH = very basic
(alkaline)
High pOH = very acidic
7 = neutral
Calculating pH (strong acids)
To
calculate, use:
pOH = -log[OH-1]
[OH-1] = hydroxide
ion concentration
WHY?
This
is because strong
bases completely
dissociate
This means that the
molarity of the base IS
THE SAME AS the
molarity of OH-1
pOH
To
-1
[OH ]:
calculate
-1
-pOH
[OH ] = 10
Combining pH and pOH
pH
+pOH = 14
The Flow Chart
What
pH
is
the pH
-if
log[H
O ]
the
[OH-1]is
3.8 x
-4
10 M?
3
+1
pH + pOH = 14
pOH
10-pH
[H3O+1]
- log[OH-1]
10-pOH
[OH-1]
Example

What is the
pOH if the
[H3O+1] is - log[H O
6.2 x 10-1
M?
3
pH
+1]
pH + pOH = 14 pOH
10-pH
- log[OH-1]
[H3O+1]
10-pOH
[OH-1]
Example
pH
- log[H3O+1]

What is the
[H3O+1] if the
[OH-1] is 1.3 x
10-8 M?
pH + pOH = 14 pOH
10-pH
- log[OH-1]
[H3O+1]
10-pOH
[OH-1]
Try It Out
 What
is the
pH if the
[OH-1] is - log[H O
3.80 x 10-4
M?
3
pH
+1]
pH + pOH = 14 pOH
10-pH
- log[OH-1]
[H3O+1]
 10.6
10-pOH
[OH-1]
Try It Out
 What
is the
pOH if the
[OH-1] is - log[H O
6.8 x 10-6
M?
3
pH
+1]
pH + pOH = 14 pOH
10-pH
- log[OH-1]
[H3O+1]
 5.2
10-pOH
[OH-1]
STOP…Worksheet Time!
Complete
Worksheet
#1 for next
class.
Wrap Up
Properties
of Acids &
Bases Review
Today…



Turn in:
 WS #1 & Get out NOTES & CALCULATOR
Our Plan:
 Review Activities (Properties, Conjugate Acid/Base,
pH calculations)
 Homework Help
 Quiz – pH calculations
 Notes
 Worksheet #2
 Wrap Up – Go Fish
Homework (Write in Planner):
 Worksheet #2 Due next class
Review
Properties
of Acids &
Bases Review
Conjugate Acid/Base
Activity
Example
H3PO4
Homework Help

10 Green
pH pH + pOH = 14 pOH
 A solution of
strontium hydroxide
with a pH of 11.4 is
to be prepared.
- log[H3O+1]
10-pH
What mass of
strontium hydroxide
would be required
- log[OH-1]
10-pOH
to make 1.00 L of
this solution?
[H3O+1]
[OH-1]
Homework Help

11Green/11 Yellow
pH pH + pOH = 14 pOH
 Calculate the pH of
a solution that
contains 5.00 g of
HNO3 in 2.00 L of - log[H3O+1]
10-pH
solution.
- log[OH-1]
[H3O+1]
10-pOH
[OH-1]
Homework Help

12 Green/9 Yellow
pH pH + pOH = 14 pOH
 A hydrochloric acid
solution has a pH of
1.70. What is the
[H3O+1] in this
- log[H3O+1]
10-pH
solution?
Considering that
HCl is a strong acid,
- log[OH-1]
10-pOH
what is the HCl
concentration of the
solution.
[H3O+1]
[OH-1]
Homework Help

13 Green/10 Yellow
pH pH + pOH = 14 pOH
 What is the molarity
of a solution of the
strong base
Ca(OH)2 in a
- log[H3O+1]
10-pH
solution that has a
pH of 10.80?
- log[OH-1]
[H3O+1]
10-pOH
[OH-1]
Your Turn to Review

Complete the table of pH values
individually. Check your work with your
neighbor. After completing the review,
you will take a quiz that looks exactly the
same with different numbers!
Review Answers
[H3O+1]
0.079 M
4.0 x 10-8 M
2.0 x 10-5 M
3.5 x 10-3 M
pH
1.1
7.4
4.7
2.5
pOH
[OH-1]
13
6.6
9.3
12
1.3 x 10-13 M
2.6 x 10-7 M
5.0 x 10-10 M
1.0 x 10-12 M
pH of Weak Acids
We
calculate the pH of weak
acids differently because they
partially dissociate
That means the concentration
of the acid IS NOT the same
as the [H3O+1]
pH of Weak Acids
We
use something called
the Ka (the acid ionization
constant)
It has been determined by
experiments and is
different for each acid
Determining Ka
Ka
= [Products]
[Reactants]
How the pH formula is derived
What
is the pH of a solution
of 0.1 M acetic acid if the Ka
for acetic acid is 1.8 x 10-5?
CH3COOH + H2O↔ CH3COO-1 + H3O+1
0.1 M
n/a
X
X
How the pH formula is derived
 Ka
= [Products]
[Reactants]
-5
1.8x10 =
2
__x ___
0.1M
x
+1
0 ],
is the [H3
which is
what we need to find pH!
How the pH formula is derived
CH3COOH + H2O↔ CH3COO-1 + H3O+1
0.1 M
n/a
X
X
(0.1M)1.8*10-5=
x2 (0.1M)
0.1M
√ 1.8*10-6= √x2
1.3 x
-3
10 =
x=
+1
[H3O ]
How the pH formula is derived
Basically,
we multiplied the
Ka by the concentration of
the acid and took the
square root of it.
Thus, the equation:
Equation for pH weak acids
+1
[H3O ]
Once
= √ Ka [HA]
+1
O ],
you find [H3
solve for pH just like
before!
Sample Problem
Find
the pH of a 0.4 M
acetic acid solution. Ka
for acetic acid is
-5
1.8 x 10 .
Sample Problem
= √ (0.4M)(1.8 x
[H3O+1] = 0.00268
[H3
+1
O ]
= -log [H3O+1]
pH = -log[0.00268]
pH = 2.57
pH
-5
10 )
Try It Out!
Find
the pOH of a
0.33M acetic acid
solution. Ka for acetic
-5
acid is 1.8 x 10 .
Try It Out!
= √ (0.33M)(1.8 x
[H3O+1] = 0.00243
[H3
+1
O ]
= -log [H3O+1]
pH = -log[0.00243]
pH = 2.61
pH
-5
10 )
Not Done Yet!
pH
+ pOH = 14
14 – 2.61 = pOH
pOH = 11.39
Let’s do a hard one from the WS
#4 on BOTH
 What is the concentration of citric acid if
the solution has a pH of 2.5? (0.012 M)

pH Practice Problems
Complete
WS # 2 by
next class!
Wrap Up
Go
Fish
Time!
Today…

Turn in:
 WS #2
 Our Plan:
 Review
 Quiz
 Notes/Videos Indicator
 Make Sherbet
 Go Fish
 Homework (Write in Planner):
 Nothing
Review
1.
2.
3.
4.
What is the [OH-1] of a 0.4 M strong
acid solution? 2.5 x 10-14
What is the pOH of a 6 x 10-4 M solution
of strong base? 3.22
What is the pH if the pOH is 2.9? 11.1
What is the pOH of a 0.8 M weak acid
solution of acetic acid. Ka for acetic
acid 1.8 x 10-5 M. 11.57
Acid – Base Demonstration
Acid – Base Demonstration
Indicators
Definition:
Compounds
whose colors are
sensitive to pH
Their color
changes as pH
changes
Indicators
interval – the pH
range over which an
indicator changes color
 Examples: phenolphthalein,
methyl red, bromthymol
blue….
 Transition
Sherbet Activity


Make an acid/base reaction in your mouth to create
the flavor of sherbet.
In a small paper cup combine the following
ingredients:






1/2 teaspoon of citric acid crystals
1 teaspoon of icing sugar
1/2 teaspoon of drink crystals
1/4 teaspoon of sodium bicarbonate (baking soda = base)
Mix the ingredients with a popsicle stick.
Enjoy the sherbet (but not all at once). It foams in
your mouth!
Wrap Up
Go
Fish
Time!
Today…
 Turn
in:
 Nothing
 Our Plan:
 Slap Jack Names
 Indicator Lab
 Wrap Up – Spoons & Slap Jack
 Homework (Write in Planner):
 Indicator Lab Today
LAB TIME!
Test every item with all of the indicators to
determine the pH by placing 10 drops of
the item to be tested in each test tube and
adding 2 drops of the indicator. Then use
the provided charts to determine the pH.
The group that gets closest to the actual
pHs will get 10 EXTRA CREDIT POINTS!
If a member of your group has an
electronic device out you are disqualified!
The Correct Answers
Item Actual pH
7-UP
Vinegar
Fruit Juice
Lime Water
Tap Water
Soapy Water
Ammonia
Sour Candy
Crushed Aspirin
3.40
1.20
3.86
2.45
6.90
3.61
12.01
3.07
3.00
Today…



Get Out:
 Notes, WS Packet, Calculator
 Indicator Lab Make Up in ELO Today
Our Plan:
 Demo – Rainbow in the Blue
 Notes – Neutralization/Titrations
 Worksheet #3
 Gizmo
 Standardize a Base Lab
Homework (Write in Planner):
 WS #3 Due Next Class
Rainbow Indicator Demos

http://www.youtube.com/watch?v=VMk3
7PX_bFI

http://www.youtube.com/watch?v=PdprN
Twb4Ks
Polyprotic Acids
Acids
such as H2SO4 ,
H3PO4 or H2CO3 that have
more than one hydrogen
(proton) to donate.
Polyprotic Acids
Ionized…
1 mole
+1
3
moles
H
of H3PO4 =
-3
1 mole PO4
Neutralization
Occurs
when equal
molar amounts of acid
and base are added.
In neutralization:
Acid + Base --> Salt + Water
Neutralization Reaction
Example:
HCl + NaOH  NaCl + H2O
Neutralization
 The
number of moles of each
substance needed depends on
the ratio of H+1 to OH-1.
 If
it’s 1:1, the same amount of each
is needed.
 If there are 2 hydrogens to every 1
hydroxide, you would need twice as
much base
Examples
6.0
_____ moles NaOH with
6.0 moles HCl
2.0
_____
moles H2SO4 with
4.0 moles KOH
Examples
9.0
_____ moles H2SO4 with
6.0 moles Al(OH)3
5.0
_____
moles H3PO4 with
15.0 moles LiOH
Neutralization
Neutralization & Titrations
 Definitions:
 Titration:
The process in which a
standard solution is added to a
solution of unknown concentration
to determine its concentration.
 End Point: The point in a titration
when the indicator changes color.
Titrations

What is needed for a titration?
1. A solution whose concentration
is known = Standard Solution
2. An accurate way to measure the
volume of that solution = Buret
3. A way to determine when the
reaction is complete = Indicator
Titration
What
is a
titration?
Buret filled
with
standard
solution
Flask filled
with solution
of unknown
concentration
Titration Video
Titrations
Acid
Base Titrations are
reactions between strong
acids and strong bases.
H+1 + OH-1  H2O
By doing a titration, you can
calculate how many moles of
acid and base there are.
Titrations
If
+1
H
the amount of either
or
OH-1 are known, the amount
of the other can be
calculated. (1:1 Ratio)
Titrations
 To
Calculate: Remember
Moles of
Molarity?
M = moles
L
Concentration
of solution
solution
Volume of
solution
Titrations
Remember
Dilutions?
MAVA = MBVB
Concentration
of Standard
Acid Solution
Volume of Concentration Volume of
Standard of Unknown
Unknown
Solution
Base Solution Solution
Example
 After
titrating, you
found that 50 mL of
0.1 M HCl was
neutralized by 29
mL of NaOH. What
was the Molarity of
the base?
Example
MAVA = MBVB
0.1 M 50 mL
Use
X
29 mL
Algebra to solve for x!
x = 0.17 M
Example 2
 After
titrating, you found that
48 mL of 0.5 M NaOH was
used to neutralize 25 mL of
HCl. How many moles of HCl
are in the flask, AND what is
its concentration?
Example
MAVA = MBVB
x
25 mL 0.5 M 48 mL
Use Algebra
x
= 0.96 M
to solve for x!
Example Continued
 Now
find the number of moles…
M = moles
L
X
0.96 M
0.025 L
x = 0.024 moles
Try It Out!
After
titrating, you found
that 53 mL of 0.05 M
NaOH was used to
neutralize 36 mL of HCl.
What was the
concentration of the HCl?
Try It Out!
MAVA = MBVB
x
36 mL 0.05 M 53 mL
Use Algebra to solve for x!
x = 0.074 M
CONGRATULATIONS!
YOU
HAVE
COMPLETED
ALL OF THE
CURRICULUM
FOR GENERAL
CHEMISTRY!
Homework Time!
Complete
WS #3 by
next
class!
Gizmo
 If
you have never logged in to
Gizmos before use the code:
 AE462EHSKZ
 AE38GSQZ5V
 AE53MQIMSV
 AE5YGBAF8Z
Wrap Up
What
3 things do you need
for a titration?
Today…

Turn in:
 WS#3
 Our Plan:
 Review
 Quiz WS#3
 Work Day
 Missing Assignments/Labs/Quizzes
 Test Review


Bluff
Homework (Write in Planner):
 Test Review Due Next Class
 TEST NEXT CLASS!
Review Problem
 Complete
the Worksheet #3
Review Problem on p. 19 of your
notes.
Today…

Turn in:
 Test Review to Check
 Our Plan:
 Station Review
 Test Review Questions
 Test
 Work Quietly/Start Final Study Guide
 Homework (Write in Planner):
 Nothing
Today…

Turn in:
 Goal Sheet
 Our Plan:
 Antacid Lab Test
 Work on Final Test Review
 Wrap Up – Present your findings to the
class
 Homework (Write in Planner):
 Nothing
Today…
Turn in:
 Antacid Lab
 Our Plan:
 Final Test Review (30 points)
 Prepare Your Notecard
 Review Board Game
 Homework (Write in Planner):
 Test Review Due Next Class

Today…
Turn in:
 Final Test Review
 Our Plan:
 Take the Final


Pencil, Scratch Paper, PT, Notecard, Calculator
 Relax/Study

Homework (Write in Planner):
 Have a Great Summer! Come back
and visit me! I’ll miss you!