Chapter 13 The Rate Law Integrated Rate Law Reaction Mechanisms Chapter 14 All sections Chapter 15 Acids and Bases 15 1 Read for general info 15 2 Nature of Acids and Bases Acids o Characterized by a sour taste o Can dissolve many metals o Can turn blue litmus paper red o Capable of neutralizing bases Some Common Acids HCL Hydrochloric Acid o Strong acid o Inorganic o Structure H Cl H2SO4 Sulfuric Acid o Strong Acid o When placed in H2O there will be dissociation o Inorganic o Structure HNO3 Nitric Acid o Strong Acid o Inorganic o Structure HC2H3O2 Acetic Acid o Weak acid o Causes vinegar s sour taste o Belongs to family of compounds called Carboxylic Acids There s a carbon chain the size of the chain varies plus H O C o Structure Non Acidic Non Ionic Hydrogens Acidic Hydrogen Bases o Bitter taste o Slippery feel o Can turn red litmus paper blue o Can neutralize acids Some Common Bases NaOH Sodium Hydroxide KOH Potassium Hydroxide NaHCO3 Sodium Bicarbonate Na2CO3 Sodium Carbonate NH3 Ammonia 15 3 Definitions of Acids Bases Arrhenius Defintion Brumsted Lowry Definition Arrhenius Definition o Acid Substance that produces H ions in aqueous solutions o Base Substance that produces OH ions in aqueous solutions Bromsted Lowry Definition HCl aq H aq Cl aq NaOH aq Na aq OH aq o Acid Proton H ion Donor o Base Proton H ion Acceptor HCl aq H2O l H3O aq Cl aq HCl acid donated a proton to H2O acting as base to yield H3O and Cl NH3 aq H2O l NH4 aq OH aq H2O acting as acid donated a proton to NH3 base to yield NH4 and OH o Water is an amphoteric substance it can act as an acid or a base o Conjugate pairs Acid on one side of reaction Conjugate Base on other side Base on one side Conjugate Acid on other side NH3 aq H2O l cid 0 NH4 aq OH aq Conjugate Acid Base NH3 aq H2O l cid 0 NH4 aq OH aq Acid Conjugate Base H2SO4 aq H2O l HSO4 aq H3O Acid Base Conj Base Conj Acid Bromsted Lowry Bromsted Lowry Acid Base October 22 2012 15 4 Acid Strength and the acid Ionization constant Ka strong acid is one that completely ionizes in solution o HA aq H20 H3O aq A aq Weak acid is partially ionized in solution o HA aq H20 H3O aq A aq Acids can be classified according to their number of protons What makes an acid strong or weak Depends on attraction between H and the anion of the acid A 1 Monoprotic acid HA 2 Diprotic acid H2A 3 Triprotic Acid H3A Acid Ionization constant Ka Smaller Ka weaker the acid S H AS The stronger the acid the weaker the conjugate base and vise versa Equilibrium constant HA aq H20 l H3O aq A aq Ka H3O A HA Ka is a measure of the strength of the acid Products reactants only use aq gas Example HF Ka 3 5 10 4 HClO Ka 2 9 10 8 HClO is the weaker acid because it has a smaller Ka ClO is the stronger conjugate base Ka is always measured in water 15 5 Autoionization of water and pH H2O l H2O l OH aq H3O aq Autoionization process above The Equilibrium Constant for autoionization is Kw Kw H3O OH Also called the product constant for water And it is also called dissociation constant for water At 25degree C Kw 1 0 10 14 o Kw will always stay the same In water H3O OH 1 0 10 7 A solution in which H3O OH 1 0 10 7 is a neutral solution An acidic solution contains an acid that creates additional H3O ions An acidic solution has H3O 1 00 10 3 M Kw H3O OH 1 0 10 14 1 0 10 3 OH OH 1 0 10 14 1 0 10 11 M 1 0 10 3 In a basic solution a base that creates additional OH ions if OH 1 0 10 2M kw H3O OH 1 0 10 14 H3O 1 0 10 2 H3O 1 0 10 14 1 0 10 12M 1 0 10 2 The pH scale Between 0 7pH acidic Between7 14 pH basic pH 7 neutral pH log H30 in pure water H30 1 0 10 7 25 degree C o pH log 1 0x10 7 7 00 pH ex calculate pH at 25 degree C for a solution with concentration of H3 1 8x10 4M o log H30 o log 1 8x10 4 o pH 3 77 7 o ACIDIC Note 1 8 is 2 sig figs the pH should have 2 decimal places October 24 2012 The pOH and other p scales P log pOH log OH 14 7 0 basic neutral acidic pOH pH 14 00 always OH H3O w 0x10 14 25 degree C For example OH 1 0x10 3 M pH pOH log OH log 1 0x10 3 3 00 always same sig figs pH 14 00 3 00 pH 11 0 7 00 BASIC SOLUTION monoprotic pH and pOH are UNITLESS other p scales pKa logka smaller the Ka weaker acid larger pKa weaker acid larger Ka stronger acid smaller pKa strong acid 13 6 finding the H3O and pH of strong and weak acid solutions going to need to know how to write dissociation problems 1 strong acid undergoes a complete dissociation HCl aq H2O H3O Cl 0 10M 10M 10M pH log 10 pH 1 00 2 weak acid only go partial dissociation Ha aq H2O H3O aq A aq 0 I 10M C x x x x x E 10 x Ka x2 0 10 x solve for x n H3O pH log H3O example find the pH of a 0 200M HNO2 solution kaHNO2 4 6x10 4 HNO2 aq H2O l H3O aq NO2 aq I 200M 0 0 x x C x E 200 x x x Ka H3O NO2 HNO2 4 6x10 4 x2 0 200 x HA I 100 ka HA I x can remove x HA i 0 200 100x4 6x10 4 0 200 0 046 can remove x acidic 4 6x10 4 x2 0 200 x2 4 6x10 4x0 200 square root both sides x 9 6x10 3 H3O 9 6x10 3 pH log 9 6x10 3 pH 2 02 Percent ionization of a weak acid Percent ionization H3O equil HA initial x 100 9 6x10 3 0 20 4 8 weak ex 15 8 a 100 M weak acid HA solution has a pH if 4 25 find ka for the acid solution HA aq H2O l H3O aq A aq I 100M 0 x C x E 100 x x pH 4 25 pH log H3O 4 25 log H3O 4 25 log H3O 10 4 25 H3O H3O 5 6x10 5 x 5 6x10 5 A equil 5 6x10 5 M Ha equil 0 100 x 100M Ka H3O A HA 5 6x10 5 5 6x10 5 0 100 0 x x mixtures of acids 3 1x10 8 1 …
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