1 Complete the following table Assume 298 K CH 201 Self Study Worksheet 6 Solution H3O pH OH pOH 1 2 3 4 3 6 10 4 1 4 10 13 1 8 10 9 2 2 10 12 3 44 12 87 8 74 11 65 2 8 10 11 7 4 10 2 5 5 10 6 4 5 10 3 10 56 1 13 5 26 2 35 2a Write out the acid dissociation reaction for chlorous acid HClO2 Ka 1 1x10 2 and the correct expression for the Ka of this acid in terms of concentrations HClO2 aq H2O l ClO2 1 aq H3O1 aq Ka ClO2 1 H3O1 HClO2 b For a 0 300 M solution what is the percent ionization estimate ionization estimate 100 x Ka co 100 x 1 1x10 2 0 300 19 c Calculate the equilibrium concentration of all species present in a 0 300 M chlorous acid solution Eq 0 300 x x x HClO2 aq H2O l ClO2 1 aq H3O1 aq x2 0 300 x 1 1 x 10 2 0 x2 0 011x 0 0033 x 0 0522 or 0 0632 but concentrations cannot be negative so x 0 0522 HClO2 0 300 0 052 0 248 M ClO2 1 H3O1 0 052 M d What is the pH of this solution pH log 5 2x10 2 1 28 Acidic e What is the ionization of this solution ionization 100 x A HA initial 100 x 0 052 0 300 17 3 3 Complete the following table Assume 298 K Ka pKa Kb pKb Acid Base HA A1 HB B1 HC C1 HD D1 1 4 10 3 1 5 10 11 3 7 10 8 6 5 10 11 2 85 10 81 7 43 10 19 7 1 10 12 6 5 10 4 2 7 10 7 1 5 10 4 11 15 3 19 6 57 3 81 4 How many mL of 6 00 M HNO3 are needed to prepare 0 500 L of a solution with a pH of 4 50 CH 201 Self Study Worksheet 6 HNO3 is a strong acid so 6 00 M HNO3 6 00 M H3O1 H3O1 10 4 50 C1V1 C2V2 3 16 x 10 5 M x 500mL 6 00 M x V2 V2 2 64 mL 5 a 8 Hydroxyquinoline is a diprotic acid H2C9H8NO1 or H2Q1 pKa1 4 91 pKa2 9 81 Write out the two acid dissociation reactions for this acid and the correct expressions for the Ka s of this acid in terms of concentrations H2Q1 aq H2O l HQ aq H3O1 aq Ka1 HQ H3O1 H2Q1 HQ aq H2O l Q1 aq H3O1 aq Ka2 Q1 H3O1 HQ b Calculate the equilibrium concentration of all species present in a 0 14 M H2Q1 solution Ka1 x2 0 14 x 10 4 91 Assume x 0 14 x2 0 14 1 23 10 5 x 1 31 10 3 H2Q1 0 14 M HQ H3O1 1 31 10 3 M Ka2 1 31 10 3 y y 1 31 10 3 y 10 9 81 Assume y 1 31 10 3 1 31 10 3 y 1 31 10 3 1 55 10 10 y Q1 1 55 10 10 Ka2 b Which is a stronger acid H2Q1 or HQ H2Q1 The one with more protons is ALWAYS stronger 6 a Write out the base association reaction for the base ammonia NH3 pKb 4 75 and the correct expression for the Kb of this base in terms of concentrations NH3 aq H2O l NH4 1 aq OH1 aq Kb NH4 1 OH1 NH3 b Calculate the equilibrium concentration of all species present in a 0 25 M ammonia solution x2 0 25 x 10 4 75 Assume x 0 25 x2 0 25 1 78 10 5 x 2 11 10 3 1 OH1 2 11 10 3 M NH3 0 25 M NH4 H3O1 1 10 14 2 11 10 3 4 74 10 12 M c What is the pH of this solution pH log 4 74 10 12 11 32 Basic 7 What is the Kb of an unknown base if a 0 30 M solution of the base has a pH of 8 02 B H2O HB OH1 0 0 i E 0 30M 1 05 10 6 0 30 M 1 05 10 6 1 05 10 6 1 05 10 6 1 05 10 6 pOH 14 pH 14 8 02 5 98 OH1 10 5 98 1 05 10 6 M Kb HB OH1 B1 1 05 10 6 2 0 30 3 6 10 12
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