A solution with an excess of H 1 ions How do we know that a chemical is an acid Most Acids start with an H in their chemical formula What are the properties of an Acid Tastes sour Turns blue litmus paper red ID: 929741
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Slide1
Acids and Bases Unit
Slide2What is an Acid?
A solution with an excess of H
+1
ions
Slide3How do we know that a chemical is an acid?
Most Acids start with an ‘H’ in their chemical formula
Slide4What are the properties of an Acid?
Tastes sour
Turns blue litmus paper red
Reacts strongly with metals
Very Corrosive
Slide5Examples of Acids
Slide6What is a Base?
A solution with an excess of (OH)
-1
ions
Slide7What is another name for a Base?
Alkali
Slide8What are the properties of a Base?
Tastes bitter
Feels slippery
Turns red litmus paper blue
Corrosive
Slide9Examples of Bases
Soap
Drano
Bleach
Chalk
Slide10More Examples of Bases
Blood Ammonia
Stop and Think?!?!
Why do you think blood is Basic and
not Acidic
?
Slide12Warm Up
Name three properties of Acids.
Name one property that both Acids and Bases have in common
.
Slide13So, how do you know if a substance is a Base or an Acid?
We use a pH scale
Slide14What does the pH scale measure?
This is a measure of the concentration of hydrogen ions
Slide15What is used to indicate the type of substance (Acid or Base)
?
Acid-Base Indicators
There is blue litmus paper and red litmus paper
The Universal indicator
Phenolphthalein
Cabbage juice
Slide16What happens to litmus paper in the presence of an Acid?
Blue litmus paper turns
RED
in the presence of an acid
Slide17What happens to litmus paper in the presence of a Base?
Red litmus paper turns
BLUE
in the presence of a Base
Slide18On the blank pH scale, label Acids, Bases and Neutral locations!
Slide19Where can Acids be found on the pH scale?
pH is less than 7
The lower the number the stronger the acid!!
Slide20Where can Bases be found on the pH scale?
pH is more than 7
The higher the number the stronger the base!!
Slide21Where can Neutral substances be found on the pH scale?
pH is equal to 7
Slide22Warm Up
What element do all acids start with?
Where can you find the strongest acids on the pH scale?
What color do acids turn litmus paper?
Slide23Let’s go back to Acids!
Slide24What is a Monoprotic
acid?
T
here is only
ONE
hydrogen [H]
+1
ion or proton
Example:
HCl
Slide25What is a Diprotic acid?
T
here are
TWO
hydrogen [H]
+1
ions or protons
Example:
H
2
SO
4
Slide26What is a Triprotic
acid?
T
here are
THREE
hydrogen [H]
+1
ions or protons
Ex. H
3
PO
4
Slide27Steps to name acids:
Identify the non-metal group first
Look at ‘green’ sheet for group name
***If it is
not
on the ‘green’ sheet it ends in
‘ide’.
Drop the non-metal ending and add new acid name
Slide28What are the acid names?
No
Oxygen
w/Oxygen
Slide29Easy way to remember!
No “
O
” use
hydro…
I
ate
something
ic
ky
And
ite
got nause
ous
Slide30HBr
H
2
CO
3
H
2
SO
3
Let’s try together: Examples
Slide31On
your own
Slide32So, how do we write the formula for an acid?
Identify the
cation
(for an acid it is always H
+1
)
Use the acid name to find the corresponding anion
Swap n’ Drop
Slide33Example
Hydrochloric acid
Cation
Anion
Swap n’ Drop
H
+1
Cl
-1
HCl
Slide34Let’s practice
Slide35Warm Up 05/10/16
For the following, name the acid and identify its type (
monoprotic
, diprotic or
triprotic
).
Acid
Formula
Acid Name
Type
of Acid
H
2
Te
H
2
CrO
4
HBrO
2
Slide36How do you name bases?
Name the metal first, the same name as on the Periodic Table
Name the hydroxide (OH)
group.
If the metal is a transition metal, the charge must be placed in parentheses ( ) in roman numeral
(
reverse swap n’ drop)
Slide37Example
Mg(OH)2
is magnesium hydroxide
Slide38Example with a Transition Metal
Cu(OH)
2
To find the charge we reverse Swap n’ Drop!
Cu
1
(OH)
2
Cu
+2
(OH)
-1
Cu(OH)
2
is
copper (II)
hydroxide
Because the Cu has a +2 charge
Slide39How do you write the formula for bases?
Treat the Base Name as a
First
and
Last
name.
Find the charge for each.
Always (OH)
-1
for the Last name for a Base.
Swap n’ Drop
Slide40Example
Slide41How to calculate pH?
You must first know the concentration of hydrogen ions (H
+1
)
Slide42How is concentration represented?
With empty square brackets, such as
[ ]
.
Slide43So, How to calculate pH?
pH= -log[H+]
Slide44Let’s practice
1. Find the pH when the hydrogen ion concentration is 0.0025 M in solution.
Ans
= 2.60
2. Find the pH
when the hydrogen ion concentration
is 3.5x10
-5
M
in solution.
Ans
= 4.46
Slide45Other important formulas?
Use these to help calculate pH when [H
+1
] is not given:
pOH
= -log[OH-]
pH +
pOH
=
14
Slide46Let’s practice using
pOH= -log[OH-
]
pH
+
pOH
=14
What is the
pOH
, in a solution that has a hydroxide concentration of 4.82x10
-5
M?
Ans
=
4.32
Will this solution be Acidic or Basic?
Slide47Do you have an Acidic or Basic solution?
Can only be determined by calculating the pH
NOT
pOH.
Be Careful!
Slide48Example 1 continued
Will
this solution be Acidic or Basic?
pH +
pOH
=14
pH
+ 4.32=
14
pH=
9.68
This solution is
Basic!
!!
Slide49On your own!
What
is the
pOH
, in a solution that has a hydroxide concentration of 2.00x10
-4
M?
Will this solution be Basic or Acidic?
Slide50Acids/Bases definitions
Slide51What is an Arrhenius Acid?
This type of Acid produces hydrogen ions [H
+1
] in solution.
Slide52What is an Arrhenius Base?
This type of Base produces hydroxide ions [OH
-
1
] in solution.
Slide53What is the problem with the Arrhenius definition?
Not all Bases produces hydroxide ions [OH
-1
]
Example: NH
3
Slide54What is a Bronsted-Lowry acid?
This type of acid
donates
hydrogen ions [H
+1
]
to another compound.
Slide55What is a Bronsted-Lowry base?
This type of base
accepts
hydrogen ions [H
+1
]
from another compound.
Slide56Did Bronsted-Lowry fix the problem?
Yes. This definition shows that substances can be bases even though they do not release OH
-
.
Slide57Example
NH
3
is a
BASE
in water. NH
3
accepts H
+
to make NH
4
Water
is itself an
ACID
.
Water donates H
+
to make OH
-
Slide58What is a conjugate acid-base pair?
These are the two compounds involved in the transfer of a hydrogen in a reaction.
Slide59Conjugate Pairs
Slide60How to identify the conjugate pairs?
Each pair is made up of the same elements
***The only difference is a hydrogen (H
+
).
Slide61Learning Check!
Label the acid, base, conjugate
acid (CA),
and conjugate
base (CB)
in each reaction:
HCl
+ OH
-
Cl
-
+ H
2
O
H
2
O + H
2
SO
4
HSO
4
-
+ H
3
O
+
What happens when an Acid and Base react?
Neutralization
Slide63What is neutralization?
[H
+
]=[OH
-
]
pH=7
Slide64What is produced in a neutralization reaction?
S
alt and water
Slide65What is a ‘salt’ made up of?
It is an ionic compoundIt contains the metal from the base
And the non-metal from the acid.