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 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- H 2 SO 4  2H + + SO 4 2- H 3 PO 4  3H + + PO 4 3-

Hydronium ion H+ when in water reacts with water to make an hydronium ion H + + H 2 O  H 3 O +

Arrhenius Base A compound that produces OH- ions when dissolved in water. NaOH  Na + + OH - Mg(OH) 2  Mg OH -

Typical Bases NaOH, sodium hydroxide KOH, potassium hydroxide NaOCH 3, Soidum methoxide 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 + H 2 O  H 3 O + + Cl - H 2 SO 4 +2 H 2 O  2H 3 O + + SO 4 2-

Base NH3 + H2O  NH4+ + OH- NaOH  Na+ + OH-

Amphoteric Water is amphoteric because it can act like an acid or base. HCl + H 2 O  H 3 O + + Cl - NH 3 + H 2 O  NH 4 + OH -

Conjugate Acid-Base Pairs NH 3 + H 2 O  NH OH - Base, acid  conjugate acid, conjugate base On the left NH 3 gained it’s a base H 2 O gave H + it’s a base On the right, now NH 4 + 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  H 2 O + NaCl H 2 SO KOH  2 H 2 O + K 2 SO 4 Label the acid, base, salt and water

Bronstead Acid-Base Reactions HCl + NH 3  NH Cl - Label the acid, base, conjugate acid, and conjugate base

Fancy Neutralization HCl + NaHCO 3  H 2 CO 3 + NaCl H 2 CO 3  H 2 O + CO 2

Acid Reactions Acids eat metals 2HCl + Mg  H 2 + MgCl 2 H 2 SO 4 + Zn  H 2 + ZnSO 4 2HCl + Fe  H 2 + FeCl 2

Acids eat oxides 2HCl + K2O  2 KCl + H2O 2HBr + MgO  H2O + MgBr2

Base Reactions Bases dissolve a few metals 2 NaOH + 2Al + 6H 2 O  2NaAl(OH) H 2

Work over break 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.