What is an Acid 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 ID: 579152
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Slide1
Acids and Bases UnitSlide2
What is an Acid?
A solution with an excess of H
+1
ionsSlide3
How do we know that a chemical is an acid?
Most Acids start with an ‘H’ in their chemical formulaSlide4
What are the properties of an Acid?
Tastes sour
Turns blue litmus paper red
Reacts strongly with metals
Very CorrosiveSlide5
Examples of AcidsSlide6
What is a Base?
A solution with an excess of (OH)
-1
ionsSlide7
What is another name for a Base?
AlkaliSlide8
What are the properties of a Base?
Tastes bitter
Feels slippery
Turns red litmus paper blue
CorrosiveSlide9
Examples of Bases
Soap
Drano
Bleach
ChalkSlide10
More Examples of Bases
Blood Ammonia
Slide11
Stop and Think?!?!
Why do you think blood is Basic and
not Acidic
?Slide12
Warm Up
Name three properties of Acids.
Name one property that both Acids and Bases have in common
.Slide13
So, how do you know if a substance is a Base or an Acid?
We use a pH scaleSlide14
What does the pH scale measure?
This is a measure of the concentration of hydrogen ions Slide15
What 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 juiceSlide16
What happens to litmus paper in the presence of an Acid?
Blue litmus paper turns
RED
in the presence of an acidSlide17
What happens to litmus paper in the presence of a Base?
Red litmus paper turns
BLUE
in the presence of a BaseSlide18
On the blank pH scale, label Acids, Bases and Neutral locations!Slide19
Where can Acids be found on the pH scale?
pH is less than 7
The lower the number the stronger the acid!!Slide20
Where can Bases be found on the pH scale?
pH is more than 7
The higher the number the stronger the base!!Slide21
Where can Neutral substances be found on the pH scale?
pH is equal to 7Slide22
Warm 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?Slide23
Let’s go back to Acids!Slide24
What is a Monoprotic
acid?
T
here is only
ONE
hydrogen [H]
+1
ion or proton
Example:
HClSlide25
What is a Diprotic acid?
T
here are
TWO
hydrogen [H]
+1
ions or protons
Example:
H
2
SO
4Slide26
What is a Triprotic
acid?
T
here are
THREE
hydrogen [H]
+1
ions or protons
Ex. H
3
PO
4Slide27
Steps 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 nameSlide28
What are the acid names?
No
Oxygen
w/Oxygen Slide29
Easy way to remember!
No “
O
” use
hydro…
I
ate
something
ic
ky
And
ite
got nause
ousSlide30
HBr
H
2
CO
3
H
2
SO
3
Let’s try together: ExamplesSlide31
On
your ownSlide32
So, 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’ DropSlide33
Example
Hydrochloric acid
Cation
Anion
Swap n’ Drop
H
+1
Cl
-1
HClSlide34
Let’s practiceSlide35
Warm 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
2Slide36
How 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)Slide37
Example
Mg(OH)2
is magnesium hydroxideSlide38
Example 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 chargeSlide39
How 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’ DropSlide40
ExampleSlide41
How to calculate pH?
You must first know the concentration of hydrogen ions (H
+1
)Slide42
How is concentration represented?
With empty square brackets, such as
[ ]
.Slide43
So, How to calculate pH?
pH= -log[H+]Slide44
Let’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
= 4.46Slide45
Other important formulas?
Use these to help calculate pH when [H
+1
] is not given:
pOH
= -log[OH-]
pH +
pOH
=
14Slide46
Let’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?Slide47
Do you have an Acidic or Basic solution?
Can only be determined by calculating the pH
NOT
pOH.
Be Careful!Slide48
Example 1 continued
Will
this solution be Acidic or Basic?
pH +
pOH
=14
pH
+ 4.32=
14
pH=
9.68
This solution is
Basic!
!!Slide49
On 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?Slide50
Acids/Bases definitionsSlide51
What is an Arrhenius Acid?
This type of Acid produces hydrogen ions [H
+1
] in solution.Slide52
What is an Arrhenius Base?
This type of Base produces hydroxide ions [OH
-
1
] in solution.Slide53
What is the problem with the Arrhenius definition?
Not all Bases produces hydroxide ions [OH
-1
]
Example: NH
3Slide54
What is a Bronsted-Lowry acid?
This type of acid
donates
hydrogen ions [H
+1
]
to another compound. Slide55
What is a Bronsted-Lowry base?
This type of base
accepts
hydrogen ions [H
+1
]
from another compound. Slide56
Did Bronsted-Lowry fix the problem?
Yes. This definition shows that substances can be bases even though they do not release OH
-
.Slide57
Example
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
-Slide58
What is a conjugate acid-base pair?
These are the two compounds involved in the transfer of a hydrogen in a reaction. Slide59
Conjugate PairsSlide60
How to identify the conjugate pairs?
Each pair is made up of the same elements
***The only difference is a hydrogen (H
+
).Slide61
Learning 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
+
Slide62
What happens when an Acid and Base react?
NeutralizationSlide63
What is neutralization?
[H
+
]=[OH
-
]
pH=7Slide64
What is produced in a neutralization reaction?
S
alt and water Slide65
What is a ‘salt’ made up of?
It is an ionic compoundIt contains the metal from the base
And the non-metal from the acid.