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Learn about the different types of acids and bases, how to name them, their properties and reactions, and their importance in various industries.
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Chapter 14 Acids and Bases
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 • Hydrochloric Acid • Ex2 HBr • Hydrobromic Acid • Ex3 H3P • Hydrophosphoric Acid
Writing formulas from names for Acids • Criss Cross charges • 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
Naming Acids • Ex6 H2SO4 • Sulfuric Acid • Ex7 H2SO3 • Sulfurous Acid • Ex8 HClO4 • Perchloric Acid • Ex9 HClO • Hypochlorous Acid
Writing Formulas From Names • Ex10 Nitric Acid • HNO3 • Ex11 Phosphorous Acid • H3PO3
Some common acids: • Sulfuric – used for fertilizer, petroleum, production of metal, paper, paint • HCl – 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
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)
Definitions of Acids • Bronsted-Lowery Acids – proton donors • Show HCl + water and HCl + ammonia • HCl + H2O H3O+(aq) + Cl-1(aq) • HCl + NH3 NH4+(aq) + Cl-1(aq) (*not Cl2!!)
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)
Molecular, Total Ionic, and Net Ionic Equations for acids: • Molecular Equation: • Zn(s) + 2 HCl(aq) ZnCl2(aq) + H 2(g) • Total Ionic Equation: • Zn(s) + 2H+1(aq) + 2Cl-1 (aq) Zn+2(aq) + 2Cl-1(aq) + H2(g) • Net Ionic Equation: • Zn(s) + 2H+1(aq) Zn+2(aq) + H2(g)
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, ).
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.
Definition of Bases • A substance that has OH- ions. Bases dissociate in water to give OH- & positive metal ions.
Types of Bases • Traditional Bases (Arrhenius) – a substance that contains hydroxide ions and dissociates to give hydroxide ions in water. • NaOH(s) + H2ONa+(aq) + OH-(aq) • Mg(OH)2(s) + H2O Mg+2(aq) + 2OH-(aq)
Types of Bases 2. Bronsted- Lowry bases – proton acceptors • NH3(g) + H2O(l) NH4+1(aq) + OH-1(aq) * Water is amphoteric. It can act as an acid or base.
Types of 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) • 2H+1(aq) + 2Cl-1(aq) + Ba+2(aq) + 2OH-1(aq) Ba+2(aq) + 2Cl-1(aq) + 2HOH(l) • 2H+1(aq) + 2OH-1(aq) 2HOH(l)
Relative Strengths of Acids and Bases • Some acids and bases are stronger than others. • Bronsted (Danish) and Lowry (English) independently discovered that acids are proton donors and bases are proton acceptors. A proton is a hydrogen ion.
Relative Strengths of Acids and Bases • Strong Acid Example: • HCl(g) + H2O(l) H3O+1(aq) + Cl-1(aq) (Acid) (Base) • Weak Base Example: • NH3(g)+ H2O(l)NH4+1(aq) + OH-1(aq) (Base) (Acid) Remember – water is amphoteric!
Conjugate Acids & Bases • Conjugate Acid: the substance that was the base and now acts as an acid. • Conjugate Base: the substance that was the acid and now acts as a base. • HCl(g)+ H2O(l) H3O+1(aq) + Cl-1(aq) (Acid) (Base)(Conjugate Acid) (Conjugate Base)
Conjugate Acids & Bases • NH3(g)+ H2O(l) NH4+1(aq) + OH-1(aq) • HF(l)+ H2O(l) H3O+1(aq) + F-1(aq)
Conjugate Acids and bases • H2CO3(aq)+ H2O(l) H3O+1(aq) + HCO3-1(aq) • The stronger the acid, the weaker the conjugate base. • Proton transfer reactions favor the production of the weaker acid and the • weaker base.
Conj. Acid/Base Practice • Complete the equation and label acid base pairs • HSO4-1(aq)+ HCO3-1(aq) • Write an equation showing how NH2-1 is a stronger base than HSO4-1
Conj. Acid/Base Practice • Which one is correct? • HSO4-1(aq) + H3O+1(aq) H2SO4(aq)+ H2O(l) (Base) (Acid) (Conj. Acid) (Conj. Base) or • HSO4-1(aq) + OH-1(aq) SO4-2(aq)+ H2O(l) (Acid) (Base) (Conj. Base) (Conj. Acid) The second reaction is favored because a weaker conjugate acid/base is produced.
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.
Reactions of Acids and Bases • Neutralization (double replacement): • Acid + Base Salt + Water • HX + MOH MX + H2O • Ex1: • HCl(aq) + NaOH(aq) NaCl(aq) + HOH(l)
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)
Reactions of Acids and Bases • Acid and metal oxide (really just an acid and a base): • Acid + Metal Oxide Salt + Water • Ex6: • H2SO4(aq) + CuO(s) • Turn CuO into Cu(OH)2 • H2SO4(aq) + Cu(OH)2 (aq) CuSO4(aq) + HOH(l) • Now, re-write the original reactants, new products, and balance. • H2SO4(aq) + CuO(s) CuSO4(aq) + H2O(l)
Reactions of Acids and Bases • Base and nonmetal oxide (really just an acid and a base • Base + Nonmetal Oxide Salt + Water • Ex7a: • CO2(g) + NaOH(aq) NaHCO3(aq)
Reactions of Acids and Bases • This is a little confusing. So these reactions will be done like: • CO2(g) + NaOH(aq) • Turn CO2 into H2CO3 • H2CO3(aq) + NaOH(aq) Na2CO3(aq) + HOH(l) • Now, re-write the original reactants, new products, and balance. • CO2(g) + 2 NaOH(aq) Na2CO3(aq) + H2O(l)
Reactions of Acids and Bases • Ex7b: • 2 CO2(g) + Ca(OH)2(aq) Ca(HCO3)2(aq) • CO2(g) + Ca(OH)2(aq) • Turn CO2 into H2CO3 • H2CO3(aq) + Ca(OH)2(aq) CaCO3(aq) + HOH(l) • Now, re-write the original reactants, new products, and balance. • CO2(g) + Ca(OH)2(aq) CaCO3(aq) + H2O(l)
Reactions of Acids and Bases • Metal oxide and nonmetal oxide • It is like an acid base reaction they yield salt. However, it does not produce water since no hydrogen is involved. • Ex8a: • MgO(s) + CO2(g) MgCO3(s) • Note: just add the nonmetal oxide to the metal oxide to determine the product. • Ex8b: • CuO(s) + SO3(g) CuSO4(s)
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 so [OH-1] = 1 x 10-7 • 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 greaterthanthe hydroxide concentration.
Kw Practice Fill in the table below: