Chemistry 19.2 1 of 50
19.2 Hydrogen Ions and Acidity To test a diagnosis of diabetic coma, a doctor orders several tests, including the acidity of the patient s blood. Results from this test will be expressed in units of ph. You will learn how the ph scale is used to indicate the acidity of a solution and why the ph scale is used. 2 of 50
19.2 Hydrogen Ions and Acidity > Hydrogen Ions from Water Hydrogen Ions from Water The reaction in which water molecules produce ions is called the self-ionization of water. 3 of 50
19.2 Hydrogen Ions and Acidity > Hydrogen Ions from Water In the self-ionization of water, a proton (hydrogen ion) transfers from one water molecule to another water molecule. 4 of 50
19.2 Hydrogen Ions and Acidity > Ion Product Constant for Water Ion Product Constant for Water How are [H + ] and [OH - ] related in an aqueous solution? 5 of 50
19.2 Hydrogen Ions and Acidity > Ion Product Constant for Water For aqueous solutions, the product of the hydrogen-ion concentration and the hydroxide-ion concentration equals 1.0 10-14. Any aqueous solution in which [H + ] and [OH - ] are equal is described as a neutral solution. 6 of 50
19.2 Hydrogen Ions and Acidity > Ion Product Constant for Water The product of the concentrations of the hydrogen ions and hydroxide ions in water is called the ion-product constant for water (K w ). 7 of 50
19.2 Hydrogen Ions and Acidity > Ion Product Constant for Water An acidic solution is one in which [H + ] is greater than [OH - ]. 8 of 50
19.2 Hydrogen Ions and Acidity > Ion Product Constant for Water Unrefined hydrochloric acid, commonly called muriatic acid, is used to clean stone buildings and swimming pools. 9 of 50
19.2 Hydrogen Ions and Acidity > Ion Product Constant for Water A basic solution is one in which [H + ] is less than [OH ]. Basic solutions are also known as alkaline solutions. 10 of 50
19.2 Hydrogen Ions and Acidity > Ion Product Constant for Water Sodium hydroxide, or lye, is commonly used as a drain cleaner. 11 of 50
SAMPLE PROBLEM 19.1 12 of 50
SAMPLE PROBLEM 19.1 13 of 50
SAMPLE PROBLEM 19.1 14 of 50
SAMPLE PROBLEM 19.1 15 of 50
Practice Problems for Sample Problem 19.1 Problem Solving 19.10 Solve Problem 10 with the help of an interactive guided tutorial. 16 of 50
19.2 Hydrogen Ions and Acidity > The ph Concept The ph Concept How is the hydrogen-ion concentration used to classify a solution as neutral, acidic, or basic? 17 of 50
19.2 Hydrogen Ions and Acidity > The ph Concept The ph of a solution is the negative logarithm of the hydrogen-ion concentration. 18 of 50
19.2 Hydrogen Ions and Acidity > The ph Concept Calculating ph 19 of 50
19.2 Hydrogen Ions and Acidity > The ph Concept A solution in which [H + ] is greater than 1 10 7 M has a ph less than 7.0 and is acidic. The ph of pure water or a neutral aqueous solution is 7.0. A solution with a ph greater than 7 is basic and has a [H + ] of less than 1 10 7 M. 20 of 50
19.2 Hydrogen Ions and Acidity The ph Concept > 21 of 50
19.2 Hydrogen Ions and Acidity > The ph Concept 22 of 50
19.2 Hydrogen Ions and Acidity > The ph Concept Calculating poh 23 of 50
19.2 Hydrogen Ions and Acidity > The ph Concept ph and Significant Figures 24 of 50
SAMPLE PROBLEM 19.2 25 of 50
SAMPLE PROBLEM 19.2 26 of 50
SAMPLE PROBLEM 19.2 27 of 50
SAMPLE PROBLEM 19.2 28 of 50
Practice Problems for Sample Problem 19.2 Problem Solving 19.12 Solve Problem 12 with the help of an interactive guided tutorial. 29 of 50
SAMPLE PROBLEM 19.3 30 of 50
SAMPLE PROBLEM 19.3 31 of 50
SAMPLE PROBLEM 19.3 32 of 50
SAMPLE PROBLEM 19.3 33 of 50
Practice Problems for Sample Problem 19.3 Problem Solving 19.14 Solve Problem 14 with the help of an interactive guided tutorial. 34 of 50
19.2 Hydrogen Ions and Acidity > Measuring ph Measuring ph What is the most important characteristic of an acid-base indicator? 35 of 50
19.2 Hydrogen Ions and Acidity > Measuring ph An indicator is a valuable tool for measuring ph because its acid form and base form have different colors in solution. 36 of 50
19.2 Hydrogen Ions and Acidity > Measuring ph Phenolphthalein changes from colorless to pink at ph 7 9. 37 of 50
SAMPLE PROBLEM 19.4 38 of 50
SAMPLE PROBLEM 19.4 39 of 50
SAMPLE PROBLEM 19.4 40 of 50
SAMPLE PROBLEM 19.4 41 of 50
Practice Problems for Sample Problem 19.4 Problem Solving 19.15 Solve Problem 15 with the help of an interactive guided tutorial. 42 of 50
19.2 Hydrogen Ions and Acidity > Measuring ph Acid-Base Indicators 43 of 50
19.2 Hydrogen Ions and Acidity > Measuring ph 44 of 50
19.2 Hydrogen Ions and Acidity > Measuring ph Universal Indicators 45 of 50
19.2 Hydrogen Ions and Acidity > Measuring ph ph Meters 46 of 50
19.2 Section Quiz. Assess students understanding of the concepts in Section 19.2. Continue to: Section Quiz -or- Launch: 47 of 50
19.2 Section Quiz. 1. If the [OH - ] in a solution is 7.65 10-3 M, what is the [H + ] of this solution? a. 7.65 10-17 M b. 1.31 10-12 M c. 2.12M d. 11.88M 48 of 50
19.2 Section Quiz. 2. The [OH - ] for four solutions is given below. Which one of the solution is basic? a. 1.0 x 10-6 M b. 1.0 x 10-8 M c. 1.0 x 10-7 M d. 1.0 x 10-14 M 49 of 50
19.2 Section Quiz. 3. What is the ph of a solution with a hydrogenion concentration of 8.5 x 10-2 M? a. 12.93 b. 8.50 c. 5.50 d. 1.07 50 of 50
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