Transcript pH to H 3 O +

Ch. 15
Titration
And pH
Ionization of Water
• _____________________: two water
molecules produce a hydronium ion and a
hydroxide ion by transfer of a proton.
15-2
Ionization of Water
In a neutral solution, ________________________.
Ionization constant of water = Kw
Kw =H3O+ OH- = 1.0 x 10-14M
If the H3O+ = 1.0 x 10-5M, the solution is _________.
___________________________, so the hydronium
concentration is greater than it would be in a neutral
solution.
15-3
Example
Example: A 1.0 x 10-4M solution of HNO3 has been prepared for a
lab. Calculate the H3O+ and OH- of this solution.
_________________________________
H3O+ = 1.0 x 10-4M
_________________________
OH- = 1.0 x 10-14M = 1.0 x 10-14M
H3O+
1.0 x 10-4M
= 1.0 x 10-10M
15-4
Practice
1) Determine the H3O+ and OH- of a solution that is 1.0 x 10-4M
Ca(OH)2.
15-5
The pH Scale
• _____: the negative of the common logarithm of the hydronium ion
concentration.
________________
= - log (1.0 x 10-7M) = 7.0
___________________________
= - log (1.0 x 10-7M) = 7.0
pH + pOH = 14.0
______________________________________________
15-6
The pH Scale
Example
Example: What is the pH of a solution if the H3O+ is
3.4 x 10-5M?
pH = -log  H3O+
= - log (3.4 x 10-5M)
On your calculator, ______________________
Keep in mind, it is the negative of the log, so change the
sign on your answer:
pH = _________
15-8
Practice
2) What is the pH of a solution if the H3O+ is
2.5 x 10-2M?
15-9
pH to  H3O+
pH = -log  H3O+
log  H3O+ = -pH
____________________
Example: What is the  H3O+, OH- if the pH is 7.52? Is the
solution acidic or basic?
 H3O+ = 10-pH = 10-7.52 ____________________________.
= 3.0 x 10-8
 OH-  = 1.0 x 10-14M = 1.0 x 10-14M = _______________
 H3O+ 
3.0 x 10-8M
pH is greater than 7.0, the solution is __________.
15-10
pH to  H3O+
3) What is the  H3O+, OH- if the pH is 12.0? Is
the solution acidic or basic?
15-11
Indicators
• ___________________: compounds whose colors are
sensitive to pH.
• _________________: the pH range over which an
indicator ___________.
• ____________: determines the pH of a solution by
measuring the voltage between two electrodes that are
placed in the solution.
15-12
Indicators
15-13
Titration
• _____________: the controlled addition and
measurement of the amount of a solution of___________
________________ required to react completely with a
measured amount of a solution of unknown concentration.
• ___________________: the point at which the two
solutions used in a titration are present in chemically
equivalent amounts.
• ____________: the point in a titration at which an
indicator changes color.
15-14
Titration
15-15
Titration
15-16
Titration
• __________________: the solution that contains
the precisely known concentration of a solute.
• __________________: a highly purified solid
compound used to check the concentration of the
known solution in a titiration.
15-17
Buffers
• Buffered Solution: resists changes in
pH with the addition of an acid or a
base.
Ch. 15
The
End!
15-19