CHAPTER 15 PROPERTIES OF ACIDS & BASES

WHAT IS AN ACID? A compound that donates a hydrogen ion (H+) when dissociated

Acids, continued Acids Generate Hydronium Ions, continued Section 1 What Are Acids and Bases? Chapter 15

ACID PROPERTIES 1.aqueous solutions have a sour taste 2.change the color of acid-base indicators 3.when reacted with an active metal, releases hydrogen gas Zn (s) + H 2 SO 4 (aq)  ZnSO 4 (aq) + H 2 (g)

ACID PROPERTIES 4.when reacted with base, produces salt and water HCl (aq) + NaOH (aq)  NaCl (s) + H 2 O (l) 5.conduct electric current 6.Turns litmus paper red

Visual Concepts Strength and Weakness of Acids and Bases Chapter 15

STRONG VS. WEAK ACIDS Strong acids dissociate completelyStrong acids dissociate completely Every H + ion breaks offEvery H + ion breaks off Weak acids dissociate incompletelyWeak acids dissociate incompletely A few H + ions break off then reformA few H + ions break off then reform

WHAT IS A BASE? A compound that accepts a hydrogen ion (H+)A compound that accepts a hydrogen ion (H+)OR contains OH - ioncontains OH - ion

Bases, continued Chapter 15 Section 1 What Are Acids and Bases?

BASE PROPERTIES 1.aqueous solutions of bases have a bitter taste 2.bases change the color of acid base indicators 3.dilute aqueous solutions of bases feel slippery

BASE PROPERTIES 4.when reacted with acid, produces salt and water 5.conduct electric current 6.Turns litmus paper blue

12 Describe the solution in each of the following as: 1) acid 2) base or 3)neutral A. soda B. soap B. soap C. coffee D. wine E. water F. grapefruit F. grapefruit Learning Check

Relationship of [H 3 O + ] and [OH - ]Relationship of [H 3 O + ] and [OH - ] Chapter 15 Section 1 What Are Acids and Bases?

DIFFERENT DEFINITIONS SHOULD BE MEMORIZED

Visual Concepts Arrhenius Acids and Bases Chapter 15

ARRHENIUS ACID A chemical compound that increases the concentration of H + ions in solutionA chemical compound that increases the concentration of H + ions in solution Good for calculating pHGood for calculating pH BASE A chemical compound that increases the concentration of OH - ions in solution Good for calculation pOH Limited to bases containing OH -

17 Arrhenius Definition In aqueous solution…In aqueous solution… HCl  H + (aq) + Cl - (aq) –Acids –Acids form hydrogen ions (H + )  In aqueous solution… BasesBases form hydroxide ions (OH - ) NaOH  Na + (aq) + OH - (aq) water

Brønsted-Lowry Classification, continued Brønsted-Lowry Acids Donate Protons, continued Section 1 What Are Acids and Bases? Chapter 15

Visual Concepts Brønsted-Lowry Acids and Bases Chapter 15

BRONSTED-LOWRY ACID A molecule or ion that is a proton (H + ) donorA molecule or ion that is a proton (H + ) donor BASE A molecule or ion that is a proton (H + ) acceptor Includes compounds w/o OH -

21 Brønsted-Lowry HCl + H 2 O  Cl – + H 3 O + –Acids –Acids are proton (H + ) donors –Bases –Bases are proton (H + ) acceptors conjugate acid conjugate base baseacid

Acids and bases come in pairs... A conjugate base is the remainder of the original acid, after it donates it’s hydrogen ionA conjugate base is the remainder of the original acid, after it donates it’s hydrogen ion A conjugate acid is the particle formed when the original base gains a hydrogen ionA conjugate acid is the particle formed when the original base gains a hydrogen ion General equation is:General equation is: HA (aq) + H 2 O (l) H 3 O + (aq) + A - (aq) Acid Base Conj acid Conj base

LEWIS ACID Electron pair acceptorElectron pair acceptor BASE Electron pair donator Why don’t we like this definition?

24 Hydronium Ion H 3 O + Often the term H + for convenience, it is more accurate to use H 3 O +Often the term H + for convenience, it is more accurate to use H 3 O + HCl (aq) + H 2 O (l)  H 3 O + (aq) + Cl – (aq) H HHHH H Cl OO – +

25 Ex.1- Water as a base H 2 O + HNO 3  H 3 O + + NO 3 – CBCA A B (ex. water) - can be an acid or a base Amphoteric - can be an acid or a base

26 Ex. 2- Water as an acid NH 3 + H 2 O  NH OH - CA CB B A

Acid-Base Titrations and pH

pH pH < 7 is acidicpH < 7 is acidic pH = 7 is neutralpH = 7 is neutral pH > 7 is basicpH > 7 is basic

Calculating pH pH = - log [H + ] pH = power of Hydrogen [H + ] = concentration in Normality

Calculating pOH pOH = - log [OH - ] pOH = power of Hydroxide [OH - ] = concentration in Normality pH + pOH = 14

CALCULATING pH FROM CONCENTRATION

SAMPLE PROBLEM A What is the pH of a 1 x M HCl solution?

SAMPLE PROBLEM A What is the pH of a 1.0 x M HCl solution? Step 1: Convert from M to N. N = ( 1.0 x ) (1) N = 1.0 x 10 -3

SAMPLE PROBLEM A What is the pH of a 1.0 x M HCl solution? Step 2: Plug-in. pH = - log [H + ] pH = - log ( 1.0 x ) pH = 3

SAMPLE PROBLEM B What is the pH of a 2.5 x M H 2 SO 4 solution?

SAMPLE PROBLEM B What is the pH of a 2.5 x M H 2 SO 4 solution? Step 1: Convert from M to N. N = (0.025) (2) N = 0.050

SAMPLE PROBLEM B What is the pH of a 2.5 x M H 2 SO 4 solution? Step 2: Plug-in. pH = - log [H + ] pH = - log (0.050) pH = 1.3

SAMPLE PROBLEM C What is the pH of a 2.5 x M NaOH solution?

SAMPLE PROBLEM C What is the pH of a 2.5 x M NaOH solution? Step 1: Convert from M to N. N = (0.025) (1) N = 0.025

SAMPLE PROBLEM C What is the pH of a 2.5 x M NaOH solution? Step 2: Plug-in. pOH = - log [OH - ] pOH = - log (0.025) pOH = 1.6

SAMPLE PROBLEM C What is the pH of a M NaOH solution? Step 3: Solve for pH. pH + pOH = 14 pH = pH = 12.4

CALCULATING CONCENTRATION FROM pH

[H 3 O + ] [H 3 O + ] = 10 -pH [H 3 O + ] = concentration of acid (N) Look for your log button. Above it – 10 x To access it, hit 2 nd F key Hit log key

The Self-Ionization of Water, continued The Self-Ionization Constant of Water, continued Section 2 Acidity, Basicity, and pH Chapter 15

[OH - ] [OH - ] = 10 -pOH [OH - ] = concentration of base (N) [H 3 O + ] [OH - ] = 1.0 x

SAMPLE PROBLEM D What is the concentration of a HCl solution with pH of 5.6?

SAMPLE PROBLEM D What is the concentration of a HCl solution with pH of 5.6? Plug into equation & calculator. [H + ] = [H+] = 2.5 x 10 -6

SAMPLE PROBLEM E What is the concentration of a Mg(OH) 2 solution with pH of 5.6?

SAMPLE PROBLEM E What is the concentration of a Mg(OH) 2 solution with pH of 5.6? Step 1: Plug into equation & calculator. [H + ] = [H+] = 2.5 x 10 -6

SAMPLE PROBLEM E What is the concentration of a Mg(OH) 2 solution with pH of 5.6? Step 2: Convert from H to OH. [H + ] = 2.5 x [H+] [OH - ] = 1.0 x (2.5 x ) [OH - ] = 1.0 x [OH - ] = 4.0 x 10 -9

NEUTRALIZATION REACTIONS

Visual Concepts Neutralization Reaction Chapter 15

NEUTRALIZATION REACTIONS The reaction of an acid and a base to form salt & waterThe reaction of an acid and a base to form salt & water H+ ions react with OH- to form waterH+ ions react with OH- to form water Predict products as in a double replacement rxn (partner swap)Predict products as in a double replacement rxn (partner swap) HCl (aq) + NaOH (aq)  H 2 O (l) + NaCl (s) H 2 O (l) + NaCl (s)

PRACTICE REACTIONS 1.HCl + LiOH  2.HNO 3 + Ca(OH) 2  3.H 2 SO 4 + Al(OH) 3 

PRACTICE REACTIONS 1.HCl + LiOH  H 2 O + LiCl 2.2 HNO 3 + Ca(OH) 2  2 H 2 O + Ca(NO 3 ) H 2 SO Al(OH) 3  6 H 2 O + Al 2 (SO 4 ) 3

NORMALITY AN ACIDS/BASES UNIT

NORMALITY (N) N = (MOLARITY) ( # OF H’s) What is N equal to in a monoprotic acid? N = M What is N equal to in a diprotic acid? N = 2 M

TITRATIONS N A V A = N B V B

Visual Concepts Titration Chapter 15

NORMALITY & NEUTRALIZATION REACTIONS N A V A = N B V B Where: N A = normality of acid V A = volume of acid N B = normality of base V B = volume of base

NORMALITY & NEUTRALIZATION REACTIONS What volume of a 0.25 M HCl solution is needed to neutralize 36 mL of 0.30 Mg(OH) 2 M? Step 1: Start with what you know. N A = (0.25 M) (1) = 0.25 N V A = X mL N B = (0.30 M) (2) = 0.60 N V B = 36 mL

NORMALITY & NEUTRALIZATION REACTIONS What volume of a 0.25 M HCl solution is needed to neutralize 36 mL of 0.30 Mg(OH) 2 M? Step 2: Substitute & Solve. N A V A = N B V B (0.25) (X) = (0.60) (36) 0.25 X = 21.6 X = 86.4 mL

Multiple Choice 1. Which of the following is not a characteristic of an acid? A.An acid changes the color of an indicator. B.An acid has a bitter taste. C.An acid ionizes in water. D.An acid produces hydronium ions in water.

Multiple Choice 1. Which of the following is not a characteristic of an acid? A.An acid changes the color of an indicator. B.An acid has a bitter taste. C.An acid ionizes in water. D.An acid produces hydronium ions in water.

Multiple Choice 2. When an acid reacts with an active metal, A.the hydronium ion concentration increases. B.the metal forms anions. C.hydrogen gas is produced. D.carbon dioxide gas is produced.

Multiple Choice 2. When an acid reacts with an active metal, A.the hydronium ion concentration increases. B.the metal forms anions. C.hydrogen gas is produced. D.carbon dioxide gas is produced.

Multiple Choice 3. Which of the following is a Brønsted- Lowry base? A. an electron pair donor B. an electron pair acceptor C. a proton donor D. a proton acceptor

Multiple Choice 3. Which of the following is a Brønsted- Lowry base? A. an electron pair donor B. an electron pair acceptor C. a proton donor D. a proton acceptor

Multiple Choice 4. What is the formula for acetic acid? A. CH 3 COOH B. HNO 3 C. HClO 4 D. HCN

Multiple Choice 4. What is the formula for acetic acid? A. CH 3 COOH B. HNO 3 C. HClO 4 D. HCN

Multiple Choice 5. Identify the salt that forms when a solution of H 2 SO 4 is titrated with a solution of Ca(OH) 2. A.calcium sulfate B.calcium hydroxide C.calcium oxide D.calcium phosphate

Multiple Choice 5. Identify the salt that forms when a solution of H 2 SO 4 is titrated with a solution of Ca(OH) 2. A.calcium sulfate B.calcium hydroxide C.calcium oxide D.calcium phosphate

Short Answer 6. How does a strong acid differ from a weak acid? Give one example of each.

Short Answer 6. How does a strong acid differ from a weak acid? Give one example of each. Answer: A strong acid is 100% ionized; a weak acid is less than 100% ionized. Possible strong acids are HCl, HI, HBr, HNO 3, H 2 SO 4, HClO 4, and HClO 3. With very few exceptions, any other acid will be a weak acid.

Multiple Choice 1. Distilled water contains A. H 2 O. B. H 3 O +. C. OH . D. All of the above

Multiple Choice 1. Distilled water contains A. H 2 O. B. H 3 O +. C. OH . D. All of the above

Multiple Choice 2. What is the pH of a M HNO 3 ? A. 1.0 B. 3.0 C. 4.0 D. 5.0

Multiple Choice 2. What is the pH of a M HNO 3 ? A. 1.0 B. 3.0 C. 4.0 D. 5.0

Multiple Choice 3. Which of the following solutions would have a pH value greater than 7? A. [OH  ] = 2.4  10  2 M B. [H 3 O + ] = 1.53  10  2 M C M HCl D. [OH  ] = 4.4  10  9 M

Multiple Choice 3. Which of the following solutions would have a pH value greater than 7? A. [OH  ] = 2.4  10  2 M B. [H 3 O + ] = 1.53  10  2 M C M HCl D. [OH  ] = 4.4  10  9 M

Multiple Choice 4.If the pH of a solution of the strong base NaOH is known, which property of the solution can be calculated? A. molar concentration B. [OH  ] C. [H 3 O + ] D. All of the above

Multiple Choice 4.If the pH of a solution of the strong base NaOH is known, which property of the solution can be calculated? A. molar concentration B. [OH  ] C. [H 3 O + ] D. All of the above

Multiple Choice 5.A neutral aqueous solution A. has a 7.0 M H 3 O + concentration. B. contains neither hydronium ions nor hydroxide ions. ions. C. has an equal number of hydronium ions and hydroxide ions. hydroxide ions. D. None of the above

Multiple Choice 5.A neutral aqueous solution A. has a 7.0 M H 3 O + concentration. B. contains neither hydronium ions nor hydroxide ions. ions. C. has an equal number of hydronium ions and hydroxide ions. hydroxide ions. D. None of the above

Multiple Choice 6.Identify the salt that forms when a solution of H 2 SO 4 is titrated with a solution of Ca(OH) 2. A. calcium sulfate B. calcium hydroxide C. calcium oxide D. calcium phosphate

Multiple Choice 6.Identify the salt that forms when a solution of H 2 SO 4 is titrated with a solution of Ca(OH) 2. A. calcium sulfate B. calcium hydroxide C. calcium oxide D. calcium phosphate

Multiple Choice 7.The pH of a solution is What is the pOH? A B. 4.8  10  7 C D. 2.1  10  8

Multiple Choice 7.The pH of a solution is What is the pOH? A B. 4.8  10  7 C D. 2.1  10  8

Multiple Choice 8.Which of the pH levels listed below is the most acidic? A.pH = 1 B.pH = 5 C.pH = 9 D.pH = 13

Multiple Choice 8.Which of the pH levels listed below is the most acidic? A.pH = 1 B.pH = 5 C.pH = 9 D.pH = 13

Short Answer 9.A solution has a pH of What is the hydronium ion concentration? Is the solution acidic or basic?

Short Answer 9.A solution has a pH of What is the hydronium ion concentration? Is the solution acidic or basic? Answer: [H 3 O + ] = 1.8  10  5 M; acidic

Extended Response 10.The hydroxide ion concentration in a solution is 1.6  10  11 M. What are the [H 3 O + ], the pH, and the pOH of the solution?

Extended Response 10.The hydroxide ion concentration in a solution is 1.6  10  11 M. What are the [H 3 O + ], the pH, and the pOH of the solution? Answer: [H 3 O + ] = 6.3  10  4 M pH = 3.20 pH = 3.20 pOH = pOH = 10.80

Extended Response 11.Write the balanced equation that represent the reaction that takes place when milk of magnesia (magnesium hydroxide) reacts with hydrochloric acid in your stomach.

Extended Response 13.Write the balanced equation that represent the reaction that takes place when milk of magnesia (magnesium hydroxide) reacts with hydrochloric acid in your stomach. Answer: