ACIDS AND BASES CHAPTER 15. 15.1: WHAT ARE ACIDS AND BASES? Objectives: To name acids and bases. To...
-
Upload
thomas-booker -
Category
Documents
-
view
241 -
download
0
Transcript of ACIDS AND BASES CHAPTER 15. 15.1: WHAT ARE ACIDS AND BASES? Objectives: To name acids and bases. To...
ACIDS AND BASES
CHAPTER 15
15.1: WHAT ARE ACIDS AND BASES?
• Objectives:• To name acids and bases.• To write formulas for acids and bases.
RULES FOR NAMING ACIDS
-ide hydro_____ic acid
-ate _____ic acid
-ite _____ous acid
*If a compound begins with hydrogen name it as an acid.
EXAMPLES: NAMING ACIDS
1. HCl• The anion is chloride (Cl-)• For an anion ending in –ide hydro___ic acid• Therefore, the name is hydrochloric acid
EXAMPLES: NAMING ACIDS
1. HCl• The anion is chloride (Cl-)• For an anion ending in –ide hydro___ic acid• Therefore, the name is hydrochloric acid
2. HNO3
• The anion is nitrate (NO3-)
• For an anion ending in –ate ___ic acid• Therefore, the name is nitric acid
EXAMPLES: NAMING ACIDS
1. HCl• The anion is chloride (Cl-)• For an anion ending in –ide hydro___ic acid• Therefore, the name is hydrochloric acid
2. H2SO4
• The anion is sulfate (SO42-)
• For an anion ending in –ate ___ic acid• Therefore, the name is sulfuric acid
3. H2SO3
• The anion sulfite (SO32-)
• For an anion ending in –ite ___ous acid• Therefore, the name acid sulfurous acid
NAME THE FOLLOWING COMPOUND: HBR
A. Bromic acidB. Bromous acidC. Hydrobromic acidD. Hydrobromous acidE. None of the above
NAME THE FOLLOWING COMPOUND: HBR
A. Bromic acidB. Bromous acidC.Hydrobromic acidD. Hydrobromous acidE. None of the above
NAME THE FOLLOWING COMPOUND: H2C2O4
A. Chromic acidB. Oxalate acidC. Dihydrogen dicarbon tetraoxideD. Oxalic acidE. None of the above
NAME THE FOLLOWING COMPOUND: H2C2O4
A. Chromic acidB. Oxalate acidC. Dihydrogen dicarbon tetraoxideD.Oxalic acidE. None of the above
PRACTICE: NAMING ACIDS
1. H2SO3
2. HF3. H3PO4
4. HNO3
5. HI
PRACTICE: NAMING ACIDS
1. H2SO3 : sulfurous acid
2. HF : hyrofluoric acid3. H3PO4 : phosphoric acid
4. HNO3 : nitric acid
5. HI : hydroiodic acid
EXAMPLES: WRITING FORMULAS FOR ACIDS
1. Sulfuric acid
• The anion is sulfate (SO42-)
• The cation is H+
• Criss-cross charges to get H2SO4
2. Carbonic acid
• The anion is carbonate (CO32-)
• The cation is H+
• Criss-cross charges to get H2CO3
H+ SO42-
H+ CO32-
H2SO4
H2CO3
PRACTICE: WRITING FORMULAS FOR ACIDS
1. Hydrochloric acid2. Nitric acid3. Phosphorous acid4. Hydroiodic acid
PRACTICE: WRITING FORMULAS FOR ACIDS
1. Hydrochloric acid: HCl2. Nitric acid: HNO3
3. Phosphorous acid: H3PO3
4. Hydroiodic acid: HI
ACIDS YOU SHOULD KNOW…
Strong Acids Weak AcidsHydrochloric
AcidPhosphoric
AcidSulfuric Acid Acetic AcidNitric Acid
SOME BASES…
Strong Bases Weak Bases
Sodium Hydroxide Ammonia
Potassium Hydroxide Sodium Carbonate
Calcium Hydroxide Potassium Carbonate
Barium Hydroxide
Sodium Phosphate
15.1: WHAT ARE ACIDS AND BASES? CONTINUED
• Objectives:• To list properties of acids and bases.
• To define acid and base.• To identify the acid, base, conjugate acid, and conjugate base in a chemical reaction.
PROPERTIES OF ACIDS
• Taste sour
• Form Hydronium Ions (H3O+)
• Conduct electricity• React with metals
PROPERTIES OF BASES
• Taste bitter• Feel slippery• Generate Hydroxide Ions (OH-)
ACID
• Arrhenius Acid: any substance that, when added to water, increases the hydronium ion (H3O+) concentration
*Note: H+ and H3O+ are used interchangeably
BASE
• Arrhenius Base: generates hydroxide ions (OH-) when dissolved in water
BRØNSTED-LOWRY ACID
• A substance that donates a proton (H+) to another substance.
BRØWNSTED-LOWRY BASE
• A substance that accepts a proton (H+).
CONJUGATE ACID AND CONJUGATE BASE
• Conjugate Acid: an acid that forms when the base gains a H+
• Conjugate Base: the base that forms when an acid loses an H+
IDENTIFY THE CONJUGATE BASE FOR THE FOLLOWING ACIDS:
Acid Conjugate Base
HCl Cl-
H2SO4
H3O+
HSO4-
HOClH2PO4
-
NH4+
IDENTIFY THE CONJUGATE BASE FOR THE FOLLOWING ACIDS:
Acid Conjugate Base
HCl Cl-
H2SO4 HSO4-
H3O+ H2O
HSO4- SO4
2-
HOCl OCl-
H2PO4- HPO4
2-
NH4+ NH3
IDENTIFY THE CONJUGATE ACID FOR THE FOLLOWING BASES:
Conjugate Acid
Base
NH4+ NH3
HCO3-
HS-
Br-
IDENTIFY THE CONJUGATE ACID FOR THE FOLLOWING BASES:
Conjugate Acid
Base
NH4+ NH3
H2CO3 HCO3-
H2S HS-
HBr Br-
IDENTIFY THE ACID, BASE, CONJUGATE ACID, AND CONJUGATE BASE IN THE FOLLOWING CHEMICAL REACTIONS:
1. HCl + OH- Cl- + H2O
acid base c. base c. acid
2. HNO3 + OH- NO3- + H2O
3. H2O + HCO3- H2CO3 + OH-
IDENTIFY THE ACID, BASE, CONJUGATE ACID, AND CONJUGATE BASE IN THE FOLLOWING CHEMICAL REACTIONS:
1. HCl + OH- Cl- + H2O
acid base c. base c. acid
2. HNO3 + OH- NO3- + H2O
acid base c. base c. acid
3. H2O + HCO3- H2CO3 + OH-
acid base c. acid c. base
AMPHOTERIC SUBSTANCES
• An amphoteric substance can donate AND accept protons.
• Example: HCO3- is amphoteric
HCO3- + NH3 CO3
2- + NH4+
Acid Base C. Base C. Acid
HCO3- + H3O+ H2CO3 + H2O
Base Acid C. Acid C. Base
15.2 ACIDITY, BASICITY, AND PH
• Objective:• To calculate the concentration of the hydronium ion and the hydroxide ion.
SELF-IONIZATION OF WATER
H2O(l) + H2O(l) H3O+(aq) + OH-(aq)
[H3O+] = [OH-] = 1.00 x 10-7 M
What is the Keq for water?
SELF-IONIZATION OF WATER
H2O(l) + H2O(l) H3O+(aq) + OH-(aq)
[H3O+] = [OH-] = 1.00 x 10-7 M
What is the Keq for water?
Keq = [H3O+][OH-] = (1.00 x 10-7)(1.00 x 10-7)
Keq = 1.00 x 10-14 = Kw
SUMMARY
Kw = [H3O+][OH-]
Kw = 1.00 x 10-14
DETERMINING [H3O+] AND [OH-] USING KW
• Step 1: Write the Kw expression.
• Step 2: Determine concentrations.• Step 3: Solve!
EXAMPLE
• What is [OH-] in a 3.00 x 10-5 M solution of HCl?
Kw = [H3O+][OH-]
1 x 10-14 = (3.00 x 10-5) [OH-] [OH-] = 3.33 x 10-10 M
PRACTICE
1. Calculate the hydronium ion concentration in an aqueous solution of KOH that has a hydroxide ion concentration of 7.24 x 10-4 M.
PRACTICE
1. Calculate the hydronium ion concentration in an aqueous solution of KOH that has a hydroxide ion concentration of 7.24 x 10-4 M.
2. What is the [OH-] in a 0.450 M solution of HNO3?
PRACTICE
3. What is [H3O+] in a solution of NaOH whose concentration is 3.75 x 10-2 M?
PRACTICE
3. What is [H3O+] in a solution of NaOH whose concentration is 3.75 x 10-2 M?
4. Calculate the hydroxide ion concentration of a 0.200 M solution of HClO4.
15.2: ACIDITY, BASICITY, AND PH CONTINUED
• Objective:• To calculate pH.
PH
• pH: A value used to represent acidity or alkalinity (basicity) of a solution.
MEASURING PH
• Indicators: dyes that turn different colors in solutions of different pH
• Examples: litmus paper, bromothymol blue, methyl orange, phenolphthalein
CALCULATING PH
pH = -log[H3O+]
EXAMPLE
• What is the pH of a solution with a 0.05 M hydronium ion concentration?
pH = -log[H3O+]
pH = -log(0.05)pH = 1.30
*Note: pH does not have units.
PRACTICE
1. What is the pH of 0.00010 M solution of nitric acid?
PRACTICE
1. What is the pH of 0.00010 M solution of nitric acid?
2. Calculate the pH if [H3O+] = 5.0 x 10-3 M.
PRACTICE
1. What is the pH of 0.00010 M solution of nitric acid?
2. Calculate the pH if [H3O+] = 5.0 x 10-3 M.
3. What is the pH of a 0.2 M solution of a strong acid?
15.2: ACIDITY, BASICITY, AND PH
• Objective:• To calculate pOH.
CALCULATING POH
pOH = -log[OH-]
pH + pOH = 14
EXAMPLE
• What is the pH and pOH of 0.00010 M solution of HNO3?
pH = -log[H3O+]pH = -log(0.00010)
pH = 4.0
pH + pOH = 144.0 + pOH = 14
pOH = 10
PRACTICE
1. What is the pH and pOH of a 0.0136 M solution of KOH?
PRACTICE
1. What is the pH and pOH of a 0.0136 M solution of KOH?
2. What is the pH and pOH of a 1.2 x 10-3 HBr solution?
PRACTICE
1. What is the pH and pOH of a 0.0136 M solution of KOH?
2. What is the pH and pOH of a 1.2 x 10-3 HBr solution?
3. What is the pH and pOH of a 2.34 x 10-5 NaOH solution?
15.2: ACIDITY, BASICITY, AND PH
• Objective:
• To calculate [H3O+] and [OH-] from pH.
CALCULATING [H3O+] AND [OH-] FROM PH
pH = -log[H3O+]
[H3O+] = 10-pH
pOH = -log[OH-]
[OH-] = 10-pOH
EXAMPLE
• What are the concentrations of the hydronium and hydroxide ions in a sample of rain that has a pH of 5.05?
[H3O+] = 10-pH
[H3O+] = 10-5.05
[H3O+] = 8.91 x 10-6 M
Kw = [H3O+][OH-] 1 x 10-14 = (8.91 x 10-6)[OH-]
[OH-] = 1.12 x 10-9 M
PRACTICE
1. What is the hydronium ion concentration in a fruit juice that has a pH of 3.3?
PRACTICE
1. What is the hydronium ion concentration in a fruit juice that has a pH of 3.3?
2. A commercial window-cleaning liquid has a pH of 11.7. What is the hydroxide ion concentration?
PRACTICE
1. What is the hydronium ion concentration in a fruit juice that has a pH of 3.3?
2. A commercial window-cleaning liquid has a pH of 11.7. What is the hydroxide ion concentration?
3. If the pH of a solution is 8.1, what is the hydronium ion concentration?
14.3: NEUTRALIZATIONS AND TITRATIONS
• Objective: To determine the concentration of an acid or base used to reach the equivalence point in a titration.
NEUTRALIZATION REACTION(ACID-BASE REACTION)
• General Equation:Acid + Base Salt + Water
• Example:HCl + NaOH NaCl + H2O
TITRATION
• Titration: Method used to determine the concentration of an acid or base.
EQUIVALENCE POINT
• Equivalence Point: Point at which the neutralization reaction is complete
END POINT
• End Point: The instant at which the indicator changes color
TITRATION CALCULATIONS
MAVA = MBVB
where A is acid and B is base
EXAMPLE
• A student titrates 40.0 mL of an HCl solution of unknown concentration with a 0.5500 M NaOH solution. The volume of base solution needed to reach the equivalence point is 24.64 mL. What is the concentration of HCl solution?
Acid (HCl) Base (NaOH)VA = 40.0 mL VB = 24.64 mLMA = ? MB = 0.5500 M
MAVA = MBVB
MA (40.0 mL) = (0.5500 M) (24.64 mL)MA = 0.3388 M
PRACTICE
1. If it takes 25 mL of 0.05 M HCl to neutralize 345 mL of NaOH solution, what is the concentration of the NaOH solution?
PRACTICE
1. If it takes 25 mL of 0.05 M HCl to neutralize 345 mL of NaOH solution, what is the concentration of the NaOH solution?
2. If it takes 50 mL of 0.5 M KOH solution to completely neutralize 125 mL of hydrochloric acid solution, what is the concentration of hyrochloric acid solution?
PRACTICE
3. How much 1.5 M Ca(OH)2 is necessary to exactly neutralize 20.0 mL of 2.5 M sulfuric acid?
PRACTICE
3. How much 1.5 M Ca(OH)2 is necessary to exactly neutralize 20.0 mL of 2.5 M sulfuric acid?
4. A 25.0 mL sample was titrated to the endpoint with 15.0 mL of 2.0 M NaOH. What is the molarity of HCl?
PRACTICE
3. How much 1.5 M Ca(OH)2 is necessary to exactly neutralize 20.0 mL of 2.5 M sulfuric acid?
4. A 25.0 mL sample was titrated to the endpoint with 15.0 mL of 2.0 M NaOH. What is the molarity of Hcl?
5. How much 0.75 M HCl is needed to completely neutralize 25.0 mL of KOH?
15.3: NEUTRALIZATIONS AND TITRATIONS
• Objective: To determine the concentration of polyprotic acids needed to reach the equivalence point in a titration.
TITRATIONS WITH POLYPROTIC ACIDS
MAVA = MBVB
With a twist…
MAVA (#H+) = MBVB(#OH-)
EXAMPLE
• What volume of a 1.366 M solution of NaOH would be required to titrate 47.22 mL of a 2.075 M solution of sulfuric acid?
Acid (H2SO4) Base (NaOH)
MA = 2.075 M MB = 1.366 M
VA = 47.22 mL VB = ? #H+ = 2 #OH- = 1
MAVA (#H+) = MBVB(#OH-)
(2.075 M) (47.22 mL) (2) = (1.366 M) (VB)(1)
VB = 143.5 mL
PRACTICE
1. How much 1.5 M NaOH is necessary to exactly neutralize 20.0 mL of 2.5 M phosphoric acid?
PRACTICE
1. How much 1.5 M NaOH is necessary to exactly neutralize 20.0 mL of 2.5 M phosphoric acid?
2. How much 0.5 M nitric acid is necessary to titrate 25.0 mL of 0.05 calcium hydroxide solution to the endpoint?