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Unit 11 -- Acid / Base Chemistry. Lundquist -- 2015. No Note Quiz for this one . Unit 11.1. Intro to Acid (HA) / Base (A - ) HA / A - Nomenclature. SELF-IONIZATION OF WATER. Water molecules collide, causing a very small number to ionize in a reversible reaction :
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Unit 11 -- Acid / Base Chemistry Lundquist -- 2015
No Note Quiz for this one Unit 11.1 Intro to Acid (HA) / Base (A-) HA / A- Nomenclature
SELF-IONIZATION OF WATER • Water molecules collide, causing a very small number to ionize in a reversible reaction: H2O(l) + H2O(l) H3O+(aq) + OH-(aq) (1 in every 10 million)
HYDRONIUM • water molecule attached to a hydrogen ion (H+) by a covalent bond • H3O+ and H+ can be used interchangeably • EXTREMEMLY reactive
SELF-IONIZATION OF WATER • Water is considered neutral since it produces equal numbers of H+ and OH- ions. • Acids increase the amount of hydronium • Bases increase the amount of hydroxide.
NAMING ACIDS • First name it as an ionic compound • First name the metal (for acids it’s always* hydrogen) • Name the anion • If only 1 capital letter, it is the root from the periodic table + “-ide” • If more than 1 capital letter, it is one of the poly atomic ions you memorized. Simply write it’s name • H2S • H2SO4 • H2SO3 *except in BF3 which is a Lewis acid, you’ll learn about in AP
NAMING ACIDS • Next change the name to an acid. If it ends in… • “-ate,” drop the hydrogen and change “-ate” to “-ic acid” • “-ite,” drop the hydrogen and change “-ite” to “-ousacid” • “-ide,” drop the “-gen” in hydrogen and change “-ide” to “-ic acid” • H2S • H2SO4 • H2SO3 *except in BF3 which is a Lewis acid, you’ll learn about in AP
NAMING BASES • NaOH • Cu(OH)2 • NH3 • Name them as an ionic compound • Name the metal • If a transition metal (any after group II, except Al) put it’s charge in roman numerals • Name the anion (always “-OH”* *except ammonia which is a Brønsted–Lowry base, which you’ll learn about later this year
WRITING THE FORMULAS FROM THE NAME Acids Hydrofluoric Acid Carbonic Acid Nitrous Acid • Change the ending • Hydro__ic acid _____ide • ______ic acid _____ate • ____ousacid _____ite • If –ide, it is on the periodic table* • If –ate, or –ite, it is a polyatomic • Put a H out in front with a subscript = |charge| *except cyanide (CN-)
WRITING THE FORMULAS FROM THE NAME Bases Write the symbol for the metal Determine the metals charge Write Hydroxide (OH) If the metals charge was greater than 1, put OH in parentheses, and put a subscript after it = |charge| • Potassium hydroxide • Calcium hydroxide • Iron (III) hydroxide
NAMING ACIDS/BASES • Do p. 10 • Do p. 11
QUIZ NEXT CLASS • ALL NOMENCLATURE • Name the acid • Give the formula • 10 questions • 10/10 = 100
I KNOW YOU FORGOT YOUR POLYATOMICS C2O42- Oxylate
Unit 11.2 HA / A- Theory The pH scale
Characteristics of Acids • React with certain metals to produce H2 gas. • Acids are corrosive. • Acids taste sour. • Causes blue litmus paper to turn pink. • Conducts electricity.
Characteristics of Bases • Taste bitter. • Feel slippery • Ex. Soap has a slippery texture. • Causes red litmus paper to turn blue. • Conducts electricity.
DEFINITION OF ACIDS AND BASES • Arrhenius Model • Acid: A substance that contains H and ionizes to produce H+ in aqueous solutions. HCl(g) → H+(aq) + Cl-(aq)
DEFINITION OF ACIDS AND BASES • Arrhenius Model • Base: A substance that contains a (OH) and dissociates to produceOH- ions in aqueous solution
DEFINITION OF ACIDS AND BASES • Problem with Arrhenius’ definition of HA/A-
DEFINITION OF ACIDS AND BASES Brønsted–Lowry Model • Acid: A substance that is a hydrogen ion (H+) donor • Also referred to as a proton donor • Base: A substance that is a hydrogen ion (H+) • Also referred to as a proton acceptor.
Note Quiz Questions 11.2 2. 3.
DEFINITION OF ACIDS AND BASES Lewis Acid-Base Theory Acids react with bases to form bonds out of non-bonded electrons Acid – electron pair acceptor Base – electron pair donor
ACID/BASE STRENGTH • Strong acids and bases are strong electrolytes; • Completely dissociate in solution • Deliver the maximum number of ions (H+/A-) to solution. • Only 6 acids, and only hydroxides of group I & II metals • H2SO4, HNO3, HClO4, HCl, HBr, HI • NaOH, KOH, Ca(OH)2 etc.
ACID/BASE STRENGTH • Weak acids and bases are weaker electrolytes • DO NOTdissociate completely in solution • Deliver smaller numbers of ions to solution. (<1%) • MOST acids/bases
Characteristics of Acids and Bases Acids Bases pH >7.1 the higher the pH value the stronger the base. • pH < 6.9 • the lower the pH value • the stronger the acid
The pH Scale • Measure of the concentration of hydronium (H3O+ or H+) • Since [H+] / [OH-] are very small numbers, scientists have adopted a shorthand method to express them
Note Quiz Questions 11.2 7. 8.
The pH Scale • Based off the self-ionization of water • At 25oC: • [H+] = 1 x 10-7 M • [OH-] = 1 x 10-7 M • Kw = [H+][OH-] = 1 x 10-14 At room temperature ALL [H+] x [OH-] must equal this
The pH Scale pH/pOH are short-hand for [H+]/[OH-] • pH = -log [H+] • pOH = -log [OH-] [H+][OH-] = 1 x 10-14 pH + pOH = pKw = 14
The pH Scale [H+] = 1.0 x 10-4 What is the pH & pOH? [H+] = 3.8 x 10-10 What is the pH & pOH? [OH-] = 1.0 x 10-2 What is the pH & pOH? [OH] = 7.9 x 10-14 What is the pH & pOH?
The pH Scale • Acidic solutions have more H+ ions than OH- ions and thus, have pH’s below 7 • Basic solutions have more OH- ions than H+ ions and thus, have pH’s above 7. • Neutral solutions have equal numbers of H+ ions and OH- ions and thus, have a pH of 7.
The pH Scale • The [H+] and [OH-] values can be calculated from the pH or pOH using the reverse process. pH = 6.0 What is the [H+] & [OH-]? pOH= 10.4 What is the [H+] & [OH-]?
MONOPROTIC, DIPROTIC Monoprotic Diprotic / Polyprotic Diprotic Have TWO H+/OH- 0.005M Ca(OH)2 1 x 10-3M H2SO4 • Have ONE H+/OH- 0.1M HCl 0.03M HC2H3O2
DO P. 14 - 15 • Thiosulfic Acid = H2S2O3 • Oxalic Acid = H2C2O3
QUIZ NEXT CLASS • label Brønsted–Lowry acid / base • Name an acid / base • Find pH • Find [OH-] • Find pOH
Unit 11.3 Neutralization ReactionsTitrations
NEUTRALIZATION • a reaction in which an acid and a base react in aqueous solution to produce a salt and water. • double replacement reaction
Not in NOTES NEUTRALIZATION DOES NOT ALWAYS MAKE A pH OF 7 • Strong HA + Strong MOH 7 • Strong HA + Weak MOH <7 • Weak HA + Strong MOH >7
Note Quiz Questions 11.3 2. 3. HCl & NaOH are both STRONG electrolytes