Acids, Bases, and Salts Ch 15 & 16 Introduction to Acids and Bases.asx

TERM PROJECT U:\My Videos\New Folder\SOS 2011.mov U:\My Videos\New Folder\SOS 2011.mov U:\My Videos\New Folder\SOS 2011.mov U:\My Videos\New Folder\SOS 2011.mov Flyers and Guidelines are posted on my.ccsd.net Flyers and Guidelines are posted on my.ccsd.net THIS IS an ALL or Nothing Grade! THIS IS an ALL or Nothing Grade! 100 for completion and meeting the deadline and 55 for not. 100 for completion and meeting the deadline and 55 for not.

Properties of Acids Ch 15.1 Acid Property #1. The word acid comes from the Latin word acere, which means "sour." All acids taste sour. Acid Property #1. The word acid comes from the Latin word acere, which means "sour." All acids taste sour. Acid Property #2. In 1663, Robert Boyle wrote that acids would make a blue vegetable dye called "litmus" turn red. Acid Property #2. In 1663, Robert Boyle wrote that acids would make a blue vegetable dye called "litmus" turn red. Acid Property #3. Acids destroy the chemical properties of bases. Acid Property #3. Acids destroy the chemical properties of bases. Properties of acids and bases.asx

Acid Property #4. Acids conduct an electric current. Acid Property #4. Acids conduct an electric current. Acid Property #5. Upon chemically reacting with an active metal, acids will evolve hydrogen gas (H 2 ). Acid Property #5. Upon chemically reacting with an active metal, acids will evolve hydrogen gas (H 2 ).

Properties of Bases Base Property #1. The word "base" has a more complex history and its name is not related to taste. All bases taste bitter. Base Property #1. The word "base" has a more complex history and its name is not related to taste. All bases taste bitter. Base Property #2. Bases are substances which will restore the original blue color of litmus after having been reddened by an acid. Base Property #2. Bases are substances which will restore the original blue color of litmus after having been reddened by an acid. Base Property #3. Bases destroy the chemical properties of acids. Base Property #3. Bases destroy the chemical properties of acids.

Base Property #4. Bases conduct an electric current. Base Property #4. Bases conduct an electric current. Base Property #5. Bases feel slippery, sometimes people say soapy. This is because they dissolve the fatty acids and oils from your skin and this cuts down on the friction between your fingers as you rub them together. Base Property #5. Bases feel slippery, sometimes people say soapy. This is because they dissolve the fatty acids and oils from your skin and this cuts down on the friction between your fingers as you rub them together.

The Acid Base Theory Ch 15.2 The three main theories regarding acids and bases are: The three main theories regarding acids and bases are: 1. Arrhenius 2. Brønsted-Lowry 3. Lewis

Svante Arrhenius ( ) Arrhenius Acids.asx

Svante Arrhenius Swedish chemist ( ) - Nobel prize winner in chemistry (1903) Swedish chemist ( ) - Nobel prize winner in chemistry (1903) one of the first chemists to explain the chemical theory of the behavior of acids and bases one of the first chemists to explain the chemical theory of the behavior of acids and bases

1. Arrhenius Definition Acids produce hydrogen ions (H 1+ ) in aqueous solution. Acids produce hydrogen ions (H 1+ ) in aqueous solution. Bases produce hydroxide ions (OH 1- ) when dissolved in water. Bases produce hydroxide ions (OH 1- ) when dissolved in water. Limited to aqueous solutions. Limited to aqueous solutions. Only one kind of base (hydroxides) Only one kind of base (hydroxides) NH 3 (ammonia) could be an Arrhenius base? NH 4 OH? NH 3 (ammonia) could be an Arrhenius base? NH 4 OH?

Polyprotic Acids Some compounds have more than 1 ionizable hydrogen. Some compounds have more than 1 ionizable hydrogen. HNO 3 nitric acid - monoprotic HNO 3 nitric acid - monoprotic H 2 SO 4 sulfuric acid - diprotic - 2 H + H 2 SO 4 sulfuric acid - diprotic - 2 H + H 3 PO 4 phosphoric acid - triprotic - 3 H + H 3 PO 4 phosphoric acid - triprotic - 3 H + Having more than one ionizable hydrogen does not mean stronger! Having more than one ionizable hydrogen does not mean stronger!

Johannes Bronsted / Thomas Lowry ( ) ( ) Bronsted Acids.asx

2. Brønsted-Lowry Definitions Broader definition than Arrhenius Broader definition than Arrhenius Acid is hydrogen-ion donor (H + or proton); base is hydrogen-ion acceptor. Acid is hydrogen-ion donor (H + or proton); base is hydrogen-ion acceptor. Acids and bases always come in pairs. Acids and bases always come in pairs. HCl is an acid. HCl is an acid. When it dissolves in water, it gives it’s proton to water. When it dissolves in water, it gives it’s proton to water. HCl(g) + H 2 O(l) H 3 O + + Cl - HCl(g) + H 2 O(l) H 3 O + + Cl - Water is a base; makes hydronium ion. Water is a base; makes hydronium ion.

Acids and bases come in pairs... Conjugate acid-bases.asx

Acids and bases come in pairs... A conjugate base is the remainder of the original acid, after it donates it’s hydrogen ion A 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 ion A conjugate acid is the particle formed when the original base gains a hydrogen ion Indicators are weak acids or bases that have a different color from their original acid and base Indicators are weak acids or bases that have a different color from their original acid and base

Acids and bases come in pairs... General equation is: General equation is: HA(aq) + H 2 O(l) H 3 O + (aq) + A - (aq) HA(aq) + H 2 O(l) H 3 O + (aq) + A - (aq) Acid + Base Conjugate acid + Conjugate base Acid + Base Conjugate acid + Conjugate base NH 3 + H 2 O NH OH 1- NH 3 + H 2 O NH OH 1- base acid c.a. c.b. base acid c.a. c.b. HCl + H 2 O H 3 O 1+ + Cl 1- HCl + H 2 O H 3 O 1+ + Cl 1- acid base c.a. c.b. acid base c.a. c.b. Amphoteric - acts as acid or base

Bases and Conjugate Acid BaseName Conjugate acid Name CH 3 OO - Acetate ion CH 3 COOH Acetic acid NH 3 Ammonia NH 4 + Ammonium H 2 PO 4 - Dihydrogen phosphate ion H 3 PO 4 Phosphoricacid HSO 4 - Hydrogen sulfate ion H 2 SO 4 Sulfuric acid OH - Hydroxide ion H20H20H20H20water NO 3 - Nitrate ion HNO 3 Nitric acid H2OH2OH2OH2Owater H30+H30+H30+H30+ Hydronium ion

Strength Strong acids and bases are strong electrolytes Strong acids and bases are strong electrolytes They fall apart (ionize) completely. They fall apart (ionize) completely. Weak acids don’t completely ionize. Weak acids don’t completely ionize. Strength different from concentration Strength different from concentration Strong-forms many ions when dissolved Strong-forms many ions when dissolved Mg(OH) 2 is a strong base- it falls completely apart when dissolved. Mg(OH) 2 is a strong base- it falls completely apart when dissolved. But, not much dissolves- not concentrated But, not much dissolves- not concentrated Strong and weak acids.asx

What about bases? Strong bases dissociate completely. Strong bases dissociate completely. Weak bases only slightly ionize in water Weak bases only slightly ionize in water

Strength vs. Concentration The words concentrated and dilute tell how much of an acid or base is dissolved in solution - refers to the number of moles of acid or base in a given volume The words concentrated and dilute tell how much of an acid or base is dissolved in solution - refers to the number of moles of acid or base in a given volume The words strong and weak refer to the extent of ionization of an acid or base The words strong and weak refer to the extent of ionization of an acid or base Is a concentrated weak acid possible? Is a concentrated weak acid possible?

Strong Acids *HNO 3 - nitric acid *HCl - hydrochloric acid *H 2 SO 4 - sulfuric acid *HClO 4 - perchloric acid *HBr - hydrobromic acid *HI - hydroiodic acid *HNO 3 - nitric acid *HCl - hydrochloric acid *H 2 SO 4 - sulfuric acid *HClO 4 - perchloric acid *HBr - hydrobromic acid *HI - hydroiodic acid

Strong Bases *LiOH - lithium hydroxide *NaOH - sodium hydroxide *KOH - potassium hydroxide *RbOH - rubidium hydroxide *CsOH - cesium hydroxide *Mg(OH) 2 - magnesium hydroxide *Ca(OH) 2 - calcium hydroxide *Sr(OH) 2 - strontium hydroxide *Ba(OH) 2 - barium hydroxide

Self-Ionization of Water H 2 O + H 2 O  H 3 O + + OH -

K w – Ionization Constant for Water Kw = (1 x )(1 x ) = 1 x In pure water at 25  C: [H 3 O + ] = 1 x mol/L [OH - ] = 1 x mol/L K w is a constant at 25  C: Kw = [H 3 O + ][OH - ]

pH Scale The pH scale is a measure of hydronium ion (H 3 O + ) concentration. The pH scale is a measure of hydronium ion (H 3 O + ) concentration. Hydronium ion concentration indicates acidity. Hydronium ion concentration indicates acidity. The higher the H 3 O +, the higher the acidity. The higher the H 3 O +, the higher the acidity. pH scale in nature.asx

pH Lab Instructions Copy down the chart below on a separate sheet of paper. 10 Samples Copy down the chart below on a separate sheet of paper. 10 Samples SAMPLE #pHAcidBaseGuess Identity

Calculating pH, pOH pH = -log (H 3 O + ) pOH = -log (OH - ) Relationship between pH and pOH pH + pOH = 14 Finding [H 3 O + ], [OH - ] from pH, pOH [H 3 O + ] = 10 -pH [OH - ] = 10 -pOH pH scale.asx

pH and pOH See Packet See Packet

Calculator Functions See Book page 488 See Book page 488

H+, OH-, and pH

pH Scale

Measuring pH with wide-range paper

Narrow-Range pH Paper

pH Indicators and their ranges

Acid-Base Reactions Neutralization Reaction - a reaction in which an acid and a base react in an aqueous solution to produce a salt and water: Neutralization Reaction - a reaction in which an acid and a base react in an aqueous solution to produce a salt and water: HCl (aq) + NaOH (aq)  NaCl (aq) + H 2 O (l) H 2 SO 4(aq) + 2KOH (aq)  K 2 SO 4(aq) + 2 H 2 O (l)

Acid-Base Reactions Acid + Base  Water + Salt Acid + Base  Water + Salt Properties related to every day: Properties related to every day: antacids depend on neutralization antacids depend on neutralization farmers use it to control soil pH farmers use it to control soil pH formation of cave stalactites formation of cave stalactites human body kidney stones from insoluble salts human body kidney stones from insoluble salts

Properties of A Salt A salt is the combination of an anion (- ion) and a cation (+ ion). A salt is the combination of an anion (- ion) and a cation (+ ion). Salts are products of the reaction between acids and bases. Salts are products of the reaction between acids and bases. Solid salts usually make crystals. Solid salts usually make crystals. If a salt dissolves in water solution, it usually dissociates into the anions and cations that make up the salt. If a salt dissolves in water solution, it usually dissociates into the anions and cations that make up the salt.

Titration Titration is the process of adding a known amount of solution of known concentration to determine the concentration of another solution Titration is the process of adding a known amount of solution of known concentration to determine the concentration of another solution

Titration The concentration of acid (or base) in solution can be determined by performing a neutralization reaction The concentration of acid (or base) in solution can be determined by performing a neutralization reaction An indicator is used to show when neutralization has occurred An indicator is used to show when neutralization has occurred Often use phenolphthalein- colorless in neutral and acid; turns pink in base Often use phenolphthalein- colorless in neutral and acid; turns pink in base

Steps - Neutralization reaction #1. A measured volume of acid of unknown concentration is added to a flask #2. Several drops of indicator added #3. A base of known concentration is slowly added

Neutralization The solution of known concentration is called the standard solution The solution of known concentration is called the standard solution added by using a buret added by using a buret Continue adding the standard solution until the indicator changes color Continue adding the standard solution until the indicator changes color called the “end point” of the titration called the “end point” of the titration

ACID-BASE Equilibria K a =Acid- Ionization Constant- K a =Acid- Ionization Constant- K b =Base Ionization Constant K b =Base Ionization Constant Constant meaning the point at which equilibria is reached. Constant meaning the point at which equilibria is reached. Weak Acid- Small constant value because of small dissociation. Weak Acid- Small constant value because of small dissociation. Strong Acid- Large Constant value because of large dissociation. Strong Acid- Large Constant value because of large dissociation.

ACID-BASE EQULIBRIA CONT: Steps to Acid- Base Equlibria problem. Steps to Acid- Base Equlibria problem. 1. Write out acid/ base equation- 1. Write out acid/ base equation- HA + H 2 O  H 3 O + + A - HA + H 2 O  H 3 O + + A - 2. Write out constant expresssion. 2. Write out constant expresssion. K b/a =[H 3 O + ] [A - ] K b/a =[H 3 O + ] [A - ] [HA - ]

ACID BASE STEPS: Step 3: Remember : Concentration of H 3 O + ion and the Conjugate base will have the same concentration values. Step 3: Remember : Concentration of H 3 O + ion and the Conjugate base will have the same concentration values. K a = (X) (X) K a = (X) (X) [conc] [conc] Step 4. Plug in values and solve.

Ammonia is a weak base. If the initial concentration of ammonia is.150M and the equilibrium concentration of OH - is 1.6 x 10 -3, calculate K b for ammonia? Step 1. Equation- NH 3 + H 2 O -> NH 4 + OH - Step 1. Equation- NH 3 + H 2 O -> NH 4 + OH - Step 2: Apply K b expression- products over reactants. Step 2: Apply K b expression- products over reactants. Step 3:plug in and solve Step 3:plug in and solve Answer: 1.7 X Answer: 1.7 X 10 -5

2.6 mol of a weak acid is added to 1.0 L of water. At equilibrium the concentration of H 3 O + is.34M What is the K a for the acid? 5.1 e e-2

What is the pH of 1.0 X M NaOH solution? 11 11

Names and Formulas of Acids An acid is a chemical that produces hydrogen ions (H 1+ ) when dissolved in water An acid is a chemical that produces hydrogen ions (H 1+ ) when dissolved in water Thus, general formula = HX, where X is a monatomic or polyatomic anion Thus, general formula = HX, where X is a monatomic or polyatomic anion HCl (g) named hydrogen chloride HCl (g) named hydrogen chloride HCl (aq) is named as an acid HCl (aq) is named as an acid Name focuses on the anion present Name focuses on the anion present

Names and Formulas of Acids 1. When anion ends with -ide, the acid starts with hydro-, and the stem of the anion has the suffix -ic followed by the word acid 2. When anion ends with -ite, the anion has the suffix -ous, then acid 3. When anion ends with -ate, the anion suffix is -ic and then acid

Names and Formulas of Bases A base produces hydroxide ions (OH 1- ) when dissolved in water. A base produces hydroxide ions (OH 1- ) when dissolved in water. Named the same way as any other ionic compound Named the same way as any other ionic compound name the cation, followed by anion name the cation, followed by anion To write the formula: write symbols; write charges; then cross (if needed) To write the formula: write symbols; write charges; then cross (if needed) SEE PACKET 18-3 Review SEE PACKET 18-3 Review

Gilbert Lewis ( )

3. Lewis Acids and Bases Gilbert Lewis focused on the donation or acceptance of a pair of electrons during a reaction Gilbert Lewis focused on the donation or acceptance of a pair of electrons during a reaction Lewis Acid - electron pair acceptor Lewis Acid - electron pair acceptor Lewis Base - electron pair donor Lewis Base - electron pair donor Most general of all 3 definitions; Lewis acids don’t even need hydrogen! Most general of all 3 definitions; Lewis acids don’t even need hydrogen!

Lewis acid and base Lewis acid and base