Chapter 19 Acids and Bases

Naming Acids Demonstration

Naming Acids 2 types of acids Binary Ternary (sometimes called oxy) binary -H and one other type of atom name them hydro _________ ic acid

Naming Acids Ex1 HCl Ex2 HBr Ex3 H3P Hydrochloric Acid Hydrobromic Acid Ex3 H3P Hydrophosphoric Acid

Writing Formulas for Acids Hydroiodic Acid 1) recognize the hydro prefix meaning it is H and the other atom 2) Write charges for H and other atom 3) Criss Cross (just like ionic compounds)

Writing formulas from names for Acids Ex4 Hydronitric Acid H3N Ex5 Hydrosulfuric Acid H2S

Naming Acids ternary (oxy) acids H with a polyatomic ion Do not start with Hydro- Change the –ate ending to –ic Change the – ite ending to –ous Hints: Recognize the polyatomic ion and then look up the name of it Change ending accordingly

Naming Acids Ex6 H2SO4 Ex7 H2SO3 Ex8 HClO4 Ex9 HClO Sulfuric Acid Sulfurous Acid Ex8 HClO4 Perchloric Acid Ex9 HClO Hypochlorous Acid

Writing Formulas from names Chloric Acid Recognize ending and no “Hydro” and determine p-ion Find formula for polyatomic ion Criss Cross H+ and polyatomic ion charges (just like ionic namig)

Writing Formulas From Names Ex10 Nitric Acid HNO3 Ex11 Phosphorous Acid H3PO3

Worksheet pkt B Naming acids and bases wks 1 and 2 Acids ONLY (only H in the front or acid in the name)

Some common acids: Sulfuric acid – used for fertilizer, petroleum, production of metal, paper, paint Hydrochloric acid – stomach acid, food processing, iron, steel Acetic acid – vinegar, fungicide, produced by fermentation Nitric acid – explosives, rubber, plastics, dyes, drugs Phosphoric acid – beverage flavoring, animal feed, detergents

Properties of Acids: Acid comes from Latin meaning acidus, or sour tasting. Affect the colors of indicators. An indicator is a chemical that shows one color in an acid and another in a base. Acids turn blue litmus red.

Properties of Acids: Acids react with bases to produce salt and water. This is called neutralization. HCl(aq) + NaOH(aq) NaCl(aq) + HOH (l) 3H2SO4(aq)+ 2Al(OH)3(aq)  Al2(SO4)3(aq) + 6 HOH (aq)

Properties of Acids: Acids ionize in water. So, they conduct electricity (electrolytes). Acids react with active metals to produce salts and hydrogen. Mg+ + 2 HCl (aq)  MgCl 2(aq) + H 2(g) Cu(s) + HCl(aq)  NR What kind of reaction is this?

Arrhenius Acids Substances that produces H+ ions when mixed with water. HCl(g) + H2O(l)  H+1(aq) + Cl-1 (aq) It is now found that: H+1(aq) + H2O(l)  H3O+1 (aq) so it is really… HCl(g) + H2O(l)  H3O+1 (aq) + Cl-1 (aq)

Types of Acids Strong - HI, HBr, HCl, HNO3, H2SO4, HClO4 (one way arrows always!) HBr + H2O  H3O+ (aq)+ Br-1 (aq) Weak – HF, H2PO4, H2CO3, H2PO4 (double arrows always!) HF (aq) + H2O (l)  H3O+1 (aq) + F-1 (aq)

Some acids donate more than 1 proton…. Monoprotic (HF) - an acid that donates one proton (one hydrogen) Ex1: Write the reaction(s) showing the complete ionization of HF. HF (aq) + H2O (l)  H3O+1 (aq) + F-1 (aq)

Some acids donate more than 1 proton…. Diprotic (H2SO4) - an acid that donates two protons (two hydrogens) Ex2: Write the reaction(s) showing the complete ionization of H2SO4. H2SO4 (aq) + H2O (l)  H3O+1 (aq) + HSO4-1 (aq) HSO4-1 (aq) + H2O(l)  H3O+1(aq) + SO4-2 (aq) __________________________________ H2SO4 (aq) + 2 H2O(l)  2 H3O +1(aq)+SO4-2(aq) *Note: When you lose a H+1, you gain a negative.

Some acids donate more than 1 proton…. Triprotic Acid: an acid that donates three protons (three hydrogens). Ex3: Write the reaction(s) showing the complete ionization of H3PO4. H3PO 4(aq) + H2O (l)  H3O +1 (aq) + H2PO4 -1 (aq) H2PO4 -1 (aq) + H2O (l)  H3O +1 (aq) + HPO4 -2 (aq) HPO4 -2 (aq) + H2O (l)  H3O +1 (aq) + PO4 -3 (aq) ________________________________________ H3PO 4(aq) + 3 H2O (l)  3 H3O +1 (aq) + PO4 -3 (aq)

Some acids donate more than 1 proton…. Diprotic and Triprotic can also be referred to as polyprotic. 2nd and 3rd ionizations are always weak (so, ).

Ex 1 and Ex 2 in notes

Wks pkt B wks 3 #1 and 2

Bases Bases are used in cleaners (floors, drains, ovens), react with fats and oils so they become water soluble, used to neutralize stomach acid (antacids), used as laxatives

Properties of Bases Bases are electrolytes. They dissociate in water. NaOH and KOH are strong electrolytes because they are both highly soluble.   Affect the colors of indicators. An indicator is a chemical that shows one color in an acid and another in a base. Bases turn red litmus blue. Bases react with acids to produce salt and water. This is called neutralization. Bases taste bitter and feel slippery. Soap is an example of a base.

Types of Bases Traditional Bases (Arrhenius) – a substance that contains hydroxide ions and dissociates to give hydroxide ions in water. NaOH(s) + H2O  Na+(aq) + OH-(aq) Mg(OH)2(s) + H2O  Mg+2(aq) + 2OH-(aq) * Water is amphoteric. It can act as an acid or base.

Types of Bases List of strong bases: List of weak bases: Hydroxides of Column I and II are strong bases List of strong bases: NaOH, KOH, CsOH, Ca(OH)2 List of weak bases: many organic compounds with N…NH3, C6H5NH2, C2H3O2-

Neutralization reactions – hydronium + hydroxide yields water It is a type of double replacement reaction. Note: H2O = HOH Acid + Base → Salt and Water General Formula: HX + MOH  MX + H2O

Neutralization Reaction Example: hydrochloric acid + barium hydroxide ( molecular, total ionic, net ionic) 2HCl(aq) + Ba(OH)2(aq)  BaCl2(aq) + 2HOH(l)

Stuff to know for Acids and Bases 2nd and 3rd ionizations are always weak. This means a double yield sign (). Memorize these strong acids. Strong means a single yield sign (). HI, HBr, HCl, HNO3, H2SO4, HClO4 All other acids get double yield signs. Strong bases include metals from column #1 and column #2 (below magnesium). Proton reactions favor the formation of the weaker acid and base.

Wks pkt A pg 1 Wks pkt B pgs 1-3

Reactions of Acids and Baes Acid + Metal (single replacement): Metal + Acid  Salt + Hydrogen Ex2: Mg(s) + 2 HCl(aq)  MgCl2(aq) + H2(g)

Reactions of Acids and Bases Acid in water: Acid + Water  Hydronium Ion + Negative Ion Ex3: HCl(g) + H2O(l)  H3O+1(aq) + Cl-1(aq)

Reactions of Acids and Bases Traditional Base (ends with OH) in water (dissociation): Base + Water  Positive Ion + Hydroxide Ex4: Fe(OH)3(s) + H2O(l)  Fe+3(aq) + 3 OH-1(aq)

Reactions of Acids and Bases Formation of acids and bases from anhydrides - synthesis (anhydride “without water”): Nonmetal oxide + water  acid Ex5a: CO2(g) + H2O(l)  H2CO3(aq) Ex5b: SO3(g) + H2O(l)  H2SO4(aq) Note: just add the nonmetal oxide to the water to determine the product.

Reactions of Acids and Bases Metal oxide + water  base Ex5c: Na2O(s) + H2O(l)  2 NaOH(aq) Ex5d: MgO(s) + H2O(l)  Mg(OH)2(aq)

Wks pkt A pgs 1-3 Wks pkt B pgs 4-8

Aqueous Solutions and the Concept of pH Tap water conducts electricity – why? – many ions present: examples: Distilled water appears to not conduct electricity, but it does – just a little, tiny bit H2O + H2O  H3O+1 + OH-1

Aqueous Solutions and the Concept of pH The normal way to express the quantity of hydronium and hydroxide ions is in moles/L (M) At 25 C0, [H3O+1] = 1 x 10-7 M so [OH-1] = 1 x 10-7 M These numbers are constant in neutral solution, so we can multiply them to get a constant We call this constant Kw - ionization constant for water Kw = [H3O+1][OH-1]

Aqueous Solutions and the Concept of pH At 25 C0, [H3O+1] = 1 x 10-7 so [OH-1] = 1 x 10-7 so Kw = 1 x 10-14 Example: If the [H3O+1] is 1 x 10-3M, then what is the [OH-1]?   The solution is acidic because the hydronium ion concentration is greater than the hydroxide concentration.

Kw Practice Fill in the table below: Beaker # [H3O+1] [OH-1] Acid or Base 1 1 x 10-5 2 1 x 10-2 3 2 x 10-4 4 4.16 x 10-6

Kw Practice Fill in the table below: Beaker # [H3O+1] [OH-1] Acid or Base 1 1 x 10-5 1 x 10-9 Acid 2 1 x 10-12 1 x 10-2 Base 3 2 x 10-4 5 x 10-11 4 2.40 x 10-9 4.16 x 10-6

Aqueous Solutions and the Concept of pH pH stands for parts per million of Hydrogen ion.

How to calculate strengths of Acids and Bases pH = - log 10 [H3O+] pOH = - log 10 [OH-] [H3O+] = 10 –pH [OH-] = 10-pOH pH + pOH = 14 Kw= [H3O+1][OH-1]

How to calculate strengths of Acids and Bases Log Review Logs are functions of exponents ex. log of 1000 = ex. log of .01 =

How to calculate strengths of Acids and Bases To convert [H3O+1] to pH pH = - log 10 [H3O+] log, #, enter, then make it positive – change the sign) [H3O+1] = pH = 1.0 x10 –1   1.0 x 10 –2 3.0 x 10 –4

How to calculate strengths of Acids and Bases To convert pH to [H3O+1] [H3O+] = 10 –pH 2nd, log, (-), #, enter [H3O+1] pH Acid or Base 2 11 5.22

pH and pOH pH + pOH = 14 pOH pH Acid or Base 2 6 5.22

How to calculate strengths of Acids and Bases [OH-] pH pOH Acid or Base 2 x 10-5 3.5 x 10-5 3.25 8.12 8.20 0.0016 2.8 x 10-11

[H+] [OH-] pH pOH Acid or Base 2 x 10-5 5 x 10-10 4.7 9.3 Acid 2.86 x 10-10 3.5 x 10-5 9.54 4.46 Base 5.62 x 10-4 1.78 x 10-11 3.25 10.75 1.32 x 10-6 8.0 x 10-9 5.88 8.12 6.0 x 10-9 1.59 x 10-6 8.20 5.8 6.25 x 10-12 0.0016 11.2 2.8 2.8 x 10-11 3.57 x 10-4 10.55 3.45

Properties of Acids and Bases Naming Acids and Bases Formula to name (and vice versa) Defn. of Acids and Bases Properties of Acids and Bases Difference and Similarities between ionization and dissociation Equations- predict products for each Acids in water (mono, di and triprotic) Bases in water Acids with active metals Neutralization reactions Nonmetal oxides in water Metal oxides in water pH Given H+ find OH- (and vice versa) Give H+ find pH (and vice versa) Given pH find pOH (and vice versa) Given OH- find pOH (and vice versa) Determine if acid or base given H+, OH-, pH or pOH