Ch. 15

1

• Ch. 15
• Titration
• And pH

2
Ionization of Water

• _____________________ two water molecules
  produce a hydronium ion and a hydroxide ion by
  transfer of a proton.
• 15-2

3
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

4
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

5
Practice

• 1) Determine the ?H3O? and ?OH-? of a solution
  that is 1.0 x 10-4M Ca(OH)2.
• 15-5

6
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

7
The pH Scale
8
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

9
Practice

• 2) What is the pH of a solution if the ?H3O? is
  
• 2.5 x 10-2M?
• -
• 15-9

10
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

11
pH to ? H3O?

• 3) What is the ? H3O?, ?OH-? if the pH is 12.0?
  Is the solution acidic or basic?
• 15-11

12
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

13
Indicators
14
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

15
Titration
16
Titration
17
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

18
Buffers

• Buffered Solution resists changes in pH with
  the addition of an acid or a base.

19

• Ch. 15
• The
• End!
• 15-19