General Organic and Biological Chemistry Fourth Edition Karen
General, Organic, and Biological Chemistry Fourth Edition Karen Timberlake Chapter 10 Acids and Bases 10. 3 Ionization of Water © 2013 Pearson Education, Inc. Lectures
Ionization of Water In the ionization of water, § H+ is transferred from one H 2 O molecule to another. § one water molecule acts as an acid, while another acts as a base. H 2 O(l) + H 2 O(l) H 3 O+(aq) + OH−(aq) © 2013 Pearson Education, Inc. Chapter 10 Section 3 2
Ion Product of Water, Kw The ion product constant, Kw, for water at 25 C § is the product of the concentrations of the hydronium and hydroxide ions. Kw = [ H 3 O+][ OH−] § is obtained from the concentrations in pure water. Kw = [ H 3 O+][ OH−] Kw = [1. 0 x 10− 7 M][1. 0 x = 1. 0 x 10− 14 © 2013 Pearson Education, Inc. Chapter 10 Section 3 3
Pure Water is Neutral In pure water, the ionization of water molecules produces small but equal quantities of H 3 O+ and OH− ions. © 2013 Pearson Education, Inc. Chapter 10 Section 3 4
![Acidic Solutions Adding an acid to pure water § increases the [H 3 O+],](http://slidetodoc.com/presentation_image_h2/fdd96a1fdfc8f60f3a32c442bbed480a/image-5.jpg "Acidic Solutions Adding an acid to pure water § increases the [H 3 O+],")
Acidic Solutions Adding an acid to pure water § increases the [H 3 O+], § decreases the [OH−], and § causes the [H 3 O+] to exceed 1. 0 x 10− 7 M. © 2013 Pearson Education, Inc. Chapter 10 Section 3 5
![Basic Solutions Adding a base to pure water, § increases the [OH−], § decreases](http://slidetodoc.com/presentation_image_h2/fdd96a1fdfc8f60f3a32c442bbed480a/image-6.jpg "Basic Solutions Adding a base to pure water, § increases the [OH−], § decreases")
Basic Solutions Adding a base to pure water, § increases the [OH−], § decreases the [H 3 O+], and § causes the [OH−] to exceed 1. 0 x 10− 7 M. © 2013 Pearson Education, Inc. Chapter 10 Section 3 6
![Comparison of [H 3 O+] and [OH−] © 2013 Pearson Education, Inc. Chapter 10](http://slidetodoc.com/presentation_image_h2/fdd96a1fdfc8f60f3a32c442bbed480a/image-7.jpg "Comparison of [H 3 O+] and [OH−] © 2013 Pearson Education, Inc. Chapter 10")
Comparison of [H 3 O+] and [OH−] © 2013 Pearson Education, Inc. Chapter 10 Section 3 7
![[H 3 O+] and [OH−] in Solutions In neutral, acidic, or basic solutions, the](http://slidetodoc.com/presentation_image_h2/fdd96a1fdfc8f60f3a32c442bbed480a/image-8.jpg "[H 3 O+] and [OH−] in Solutions In neutral, acidic, or basic solutions, the")
[H 3 O+] and [OH−] in Solutions In neutral, acidic, or basic solutions, the Kw at 25 C is always 1. 0 x 10− 14. © 2013 Pearson Education, Inc. Chapter 10 Section 3 8
![Guide to Calculating [H 3 O+] and [OH−] © 2013 Pearson Education, Inc. Chapter](http://slidetodoc.com/presentation_image_h2/fdd96a1fdfc8f60f3a32c442bbed480a/image-9.jpg "Guide to Calculating [H 3 O+] and [OH−] © 2013 Pearson Education, Inc. Chapter")
Guide to Calculating [H 3 O+] and [OH−] © 2013 Pearson Education, Inc. Chapter 10 Section 3 9
![Calculating [H 3 O+] What is the [H 3 O+] of a solution if](http://slidetodoc.com/presentation_image_h2/fdd96a1fdfc8f60f3a32c442bbed480a/image-10.jpg "Calculating [H 3 O+] What is the [H 3 O+] of a solution if")
Calculating [H 3 O+] What is the [H 3 O+] of a solution if [OH−] is 5. 0 x 10− 8 M? Step 1 Write the Kw for water. Kw = [H 3 O+ ][OH− ] Step 2 Solve the Kw for the unknown [H 3 O+] = 1. 0 x 10− 14 [OH−] Step 3 Substitute the known [OH−] into the equation and calculate. [H 3 O+] = 1. 0 x 10 © 2013 Pearson Education, Inc. Chapter 10 Section 3 10
![Learning Check If lemon juice has [H 3 O+] of 2 x 10− 3](http://slidetodoc.com/presentation_image_h2/fdd96a1fdfc8f60f3a32c442bbed480a/image-11.jpg "Learning Check If lemon juice has [H 3 O+] of 2 x 10− 3")
Learning Check If lemon juice has [H 3 O+] of 2 x 10− 3 M, what is the [OH−] of the solution? A. 2 x 10− 11 M B. 5 x 10− 11 M C. 5 x 10− 12 M © 2013 Pearson Education, Inc. Chapter 10 Section 3 11
![Solution If lemon juice has [H 3 O+] of 2 x 10− 3 M,](http://slidetodoc.com/presentation_image_h2/fdd96a1fdfc8f60f3a32c442bbed480a/image-12.jpg "Solution If lemon juice has [H 3 O+] of 2 x 10− 3 M,")
Solution If lemon juice has [H 3 O+] of 2 x 10− 3 M, what is the [OH−] of the solution? Step 1 Write the Kw for water. Kw = [H 3 O+][OH−] = 1. 0 x 10− 14 Step 2 Solve the Kw for the unknown [OH−] = 1. 0 x 10− 14 [H 3 O+ ] Step 3 Substitute the known [H 3 O+] into the equation and calculate. [2 x 10− 3 ] © 2013 Pearson Education, Inc. Chapter 10 Section 3 Answer is C. 12
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