a Calculate the pH of 010 M methylammonium chloride CH 3 NH 3 Cl K b for CH 3

A calculate the ph of 010 m methylammonium chloride

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105 a.Calculate the pH of 0.10 M methylammonium chloride (CH3NH3Cl). . + + + 18
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Chem 162-2008 6 th week recitation 19 SMALLER ATOM SMALLER ION HIGHER FIRST IONIZATION ENERGY HIGHER FIRST ELECTRON AFFINITY HIGHER ELECTRONEGATIVITY LESS METALLIC PROPERTY POOR REDUCING AGENT GOOD OXIDIZING AGENT
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Chem 162-2008 6 th week recitation 20 PERIODIC TABLE AND PERIODIC PROPERTIES
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RELATIONSHIP BETWEEN STRUCTURE AND STRENGTH OF ACIDS STRENGTHS OF ACIDS (Listed in order of priority) (1) Inversely related to strength of H—Z bond. - Governed by BOND DISTANCE - and to a lesser extent by electronegativity (2) Directly related to polarity of molecules - Governed by ELECTRONEGATIVITY Chem 162-2008 6 th week recitation 21
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EFFECT OF BOND DISTANCE VS. ELECTRONEGATIVITY ON ACID STRENGTH BOND DISTANCE ELECTRONEGATIVITY Chem 162-2008 6 th week recitation 22 F H I H Short bond distance = Strong bond = relatively weak acid (Strong electronegativity of minor importance) Long bond distance = Weak bond = relatively strong acid (Weak electronegativity of minor importance) I F O O H H ~ Equal O─H bond distance Strong F electronegativity = Weak O─H bond = Relatively strong acid ~ Equal O─H bond distance Weak I electronegativity = Strong O─H bond = Relatively weak acid 1+ 1+ 6+ 6+ 7+ 7+ 1+ 1+ 7+ 7+
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GENERALIZATIONS RELATIONSHIPS BETWEEN STRUCTURE AND STRENGTHS OF ACIDS AND BASES Vertical group binary acids: Acid strength increases as period number increases. All other acids: Acid strength increases as electronegativity increases. Chem 162-2008 6 th week recitation 23
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CHEM162-2007 5 TH AND 6 TH WEEK COMBINED RECITATION CHAPTER 14 - ACID AND BASE EQUILIBRIARELATIONSHIP BETWEEN ACID AND BASE STRUCTUE AND STRENGTH115ET note: Discuss acid strength depending upon polarizability of bond and strength of bond.Place the species in each of the following groups in order of increasing acid strength. a. H 2 O, H 2 S, H 2 Se (bond energies: H-O, 467 kJ/mol; H-S, 363 kJ/mol; H-Se, 276 kJ/mol) H ·· : O 467 H H ·· : S 363 H H ·· : Se 276 H The two factors that are important for acidity are polarity and bond strength. Going across a row in the periodic table the differences in bond strength are small, so polarity (differences in electronegativity) is the more important factor. Going down a group in the periodic table the differences in bond strengths are very large, so bond strength is the more important factor. Hence, H 2 O < H 2 S < H 2 Se Chem 162-2008 6 th week recitation 24
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  • Spring '08
  • siegal
  • pH, Acids, Weak acid, H2O

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