250 likes | 332 Vues
Chemistry SM-1232 Week 7 Lesson 1. Dr. Jesse Reich Assistant Professor of Chemistry Massachusetts Maritime Academy Fall 2008. Class Today. YES class on Friday Chapter 13 HW due, quiz due Today Chapter 14: Acids and Bases. Acids. Properties include: Sour taste Dissolve many metals
E N D
Chemistry SM-1232Week 7 Lesson 1 Dr. Jesse Reich Assistant Professor of Chemistry Massachusetts Maritime Academy Fall 2008
Class Today • YES class on Friday • Chapter 13 HW due, quiz due • Today Chapter 14: Acids and Bases
Acids • Properties include: • Sour taste • Dissolve many metals • Turn litmus paper red • Can have strong smells
Typical Acids • Sulfuric Acid • Nitric Acid • Acetic Acid • Carboxylic acids • Citric Acid • Malic Acid • Hydrochloric Acid • What’s common to all acid names?
Bases • Properties: • Bitter taste • Feel slippery • Turn litmus paper blue • Some have strong smells
Typical Bases • Sodium hydroxide • Potassium hydroxide • Magnesium hydroxide • Sodium bicarbonate • Sodium sulfate • Lithium phosphate • (ammonia) • What are common pieces to base names?
Acid and Base Definitions • 1: Arrhenius Definition • Acid: produces H+ ions in aqueous solutions, also just called protons • Base: produces OH- ions in aqueous solutions
Arrhenius acid • HCl H+ + Cl- • H2SO4 2H+ + SO42- • H3PO4 3H+ + PO43-
Hydronium ion • H+ when in water reacts with water to make an hydronium ion • H+ + H2O H3O+
Arrhenius Base • A compound that produces OH- ions when dissolved in water. • NaOH Na+ + OH- • Mg(OH)2 Mg2+ + 2OH-
Typical Bases • NaOH, sodium hydroxide • KOH, potassium hydroxide • NaOCH3, Soidummethoxide • Calcium Carbonate
Bronsted-Lowry Definition • This definition rests on the transfer of H+ ions. • Bronsted acid is a proton H+ donor • Bronsted base is a proton H+ acceptor
Acid Example • HCl + H2O H3O++ Cl- • H2SO4 +2 H2O 2H3O+ + SO42-
Base • NH3 + H2O NH4+ + OH- • NaOH Na+ + OH-
Amphoteric • Water is amphoteric because it can act like an acid or base. • HCl + H2O H3O++ Cl- • NH3 + H2O NH4+ OH-
Conjugate Acid-Base Pairs • NH3 + H2O NH4+ + OH- • Base, acid conjugate acid, conjugate base • On the left NH3 gained it’s a base • H2O gave H+ it’s a base • On the right, now NH4+ has an H+ to give so it’s the conjugate acid • OH- lost the H+ so now it’s the conjugate base
Acid Base Reactions • Neutralization • Acid Reactions • Base Reactions
Neutralization • Most common reaction! • For Arrhenius acid Base Reactions: • Acid + Base = Water + Salt • For Bronstead acid base reactions: • AcidH+ + Base- conjugate base- + conjugate acid+
Arrhenius Acid base Reactions • HCl + NaOH H2O + NaCl • H2SO4 + 2 KOH 2 H2O + K2SO4 • Label the acid, base, salt and water
Bronstead Acid-Base Reactions • HCl + NH3 NH4+ + Cl- • Label the acid, base, conjugate acid, and conjugate base
Fancy Neutralization • HCl + NaHCO3 H2CO3 + NaCl • H2CO3 H2O + CO2
Acid Reactions • Acids eat metals • 2HCl + Mg H2 + MgCl2 • H2SO4 + Zn H2 + ZnSO4 • 2HCl + Fe H2 + FeCl2
Acids eat oxides • 2HCl + K2O 2 KCl + H2O • 2HBr + MgO H2O + MgBr2
Base Reactions • Bases dissolve a few metals • 2 NaOH + 2Al + 6H2O 2NaAl(OH)4 + 3 H2
Work over break • 14.4-14.7 copy example problems. They are a pain. They will take time. Plan for it. Be sure to read in chapter 14 up through page 509.