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Edit Comment Close Premium member Presentation Transcript Acids and Bases: Acids and Bases PGCC CHM 101 SinexGeneral properties: General properties ACIDS Taste sour Turn litmus React with active metals – Fe, Zn React with bases BASES Taste bitter Turn litmus Feel soapy or slippery (react with fats to make soap) React with acids blue to red red to blueDefinitions: Definitions Acids – produce H+ Bases - produce OH- Acids – donate H+ Bases – accept H+ Acids – accept e- pair Bases – donate e- pair Arrehenius Bronsted-Lowry Lewis only in water any solvent used in organic chemistry, wider range of substancesExamples: Examples Arrhenius Bronsted-Lowry Lewis HCl NaOH HCl NH3 :NH3 BF3 HCN The hydrogen ion in aqueous solution H+ + H2O H3O+ (hydronium ion) The Bronsted-Lowry Concept: The Bronsted-Lowry Concept Conjugate pairs HCl Cl- CH3COOH CH3COO- NH4+ NH3 HNO3 NO3- How does a conjugate pair differ? H+ transferNeutralization: Neutralization In general: Acid + Base Salt + Water All neutralization reactions are double displacement reactions. HCl + NaOH NaCl + HOH HCl + Mg(OH)2 H2SO4 + NaHCO3 Slide7: H2O H+ + OH- Does pure water conduct electrical current? (H+)(OH-) = 10-14 For pure water: (H+) = (OH-) = 10-7M This is neutrality and at 25oC is a pH = 7. Water is a very, very, very weak electrolyte. How are (H+) and (OH-) related? waterSlide8: HA Let’s examine the behavior of an acid, HA, in aqueous solution. What happens to the HA molecules in solution?Slide9: HA H+ A- Strong Acid 100% dissociation of HA Would the solution be conductive?Slide10: HA H+ A- Weak Acid Partial dissociation of HA Would the solution be conductive?Slide11: HA H+ A- Weak Acid HA H+ + A- At any one time, only a fraction of the molecules are dissociated.Strong and Weak Acids/Bases: Strong and Weak Acids/Bases Strong acids/bases – 100% dissociation into ions HCl NaOH HNO3 KOH H2SO4 Weak acids/bases – partial dissociation, both ions and molecules CH3COOH NH3 Slide13: pH 2 3 4 5 6 7 8 9 10 11 12 neutral @ 25oC (H+) = (OH-) distilled water acidic (H+) > (OH-) basic or alkaline (H+) < (OH-) natural waters pH = 6.5 - 8.5 normal rain (CO2) pH = 5.3 – 5.7 acid rain (NOx, SOx) pH of 4.2 - 4.4 in Washington DC area 0-14 scale for the chemists fish populations drop off pH < 6 and to zero pH < 5Slide14: You are here! http://nadp.sws.uiuc.edu/isopleths pH of Rainwater across United States in 2001 Why is the eastern US more acidic? air massesWhat is acid rain?: What is acid rain? CO2 (g) + H2O H2CO3 H+ + HCO3- Dissolved carbon dioxide lowers the pH Atmospheric pollutants from combustion NO, NO2 + H2O … HNO3 SO2, SO3 + H2O … H2SO4 both strong acids pH < 5.3Slide16: Behavior of oxides in water– Group A basic amphoteric acidic 3A 4A 5A 6A 7A 1A 2A 8A Group B basic: Na2O + H2O 2NaOH (O-2 + H2O 2OH-) acidic: CO2 + H2O H2CO3 Slide17: When life goes either way amphoteric (amphiprotic) substances HCO3- H2CO3 CO3-2 Acting like a base Acting like an acid accepts H+ donates H+Slide18: pH 1 2 3 4 5 6 8 9 10 11 The biological view in the human body gastric juice vaginal fluid urine saliva cerebrospinal fluid blood pancreatic juice bile acidic basic/alkaline 7 Tortora & Grabowski, Prin. of Anatomy & Physiology, 10th ed., Wiley (2003)Slide19: Does the pH influence the activity of an enzyme? Trypsin is a digestive enzyme. Where? Intestinal pH range 7.0-8.5Slide20: The amino acid glycine - amphoteric It’s an acid and a base! Loss of H+ Gain of H+ H2N-CH2-COOH H3N+-CH2-COOH H2N-CH2-COO- Chime structureSlide21: The amino acid glycine - Zwitterion formation Transfer of H+ from carboxylic acid group to amine group. H2N-CH2-COOH H3N+-CH2-COO- + - A dipolar ion forms. intramolecular acid-base reaction Chime structureSlide22: Show how water can be amphoteric. H2OSlide23: Dilution water (solvent) solute concentrated, Minitial diluted, Mfinal adding water lowers the solute concentration moles of solute remain constant Vinitial Vfinal molesinitial = molesfinal Mfinal x Vfinal = Minitial x VinitialSlide24: Titration Calculation HCl + NaOH NaCl + HOH at equivalence point: moleHCl = moleNaOH moles = M x VL Macid x Vinitial acid = Mbase x Vburet A way to analyze solutions! indicator You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
A B GenX Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINTLite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 670 Category: Education License: All Rights Reserved Like it (2) Dislike it (0) Added: January 03, 2008 This Presentation is Public Favorites: 4 Presentation Description No description available. Comments Posting comment... By: kuljit (20 month(s) ago) it is a good presentation....... it will be praised more when more people can watch it after download........ Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript Acids and Bases: Acids and Bases PGCC CHM 101 SinexGeneral properties: General properties ACIDS Taste sour Turn litmus React with active metals – Fe, Zn React with bases BASES Taste bitter Turn litmus Feel soapy or slippery (react with fats to make soap) React with acids blue to red red to blueDefinitions: Definitions Acids – produce H+ Bases - produce OH- Acids – donate H+ Bases – accept H+ Acids – accept e- pair Bases – donate e- pair Arrehenius Bronsted-Lowry Lewis only in water any solvent used in organic chemistry, wider range of substancesExamples: Examples Arrhenius Bronsted-Lowry Lewis HCl NaOH HCl NH3 :NH3 BF3 HCN The hydrogen ion in aqueous solution H+ + H2O H3O+ (hydronium ion) The Bronsted-Lowry Concept: The Bronsted-Lowry Concept Conjugate pairs HCl Cl- CH3COOH CH3COO- NH4+ NH3 HNO3 NO3- How does a conjugate pair differ? H+ transferNeutralization: Neutralization In general: Acid + Base Salt + Water All neutralization reactions are double displacement reactions. HCl + NaOH NaCl + HOH HCl + Mg(OH)2 H2SO4 + NaHCO3 Slide7: H2O H+ + OH- Does pure water conduct electrical current? (H+)(OH-) = 10-14 For pure water: (H+) = (OH-) = 10-7M This is neutrality and at 25oC is a pH = 7. Water is a very, very, very weak electrolyte. How are (H+) and (OH-) related? waterSlide8: HA Let’s examine the behavior of an acid, HA, in aqueous solution. What happens to the HA molecules in solution?Slide9: HA H+ A- Strong Acid 100% dissociation of HA Would the solution be conductive?Slide10: HA H+ A- Weak Acid Partial dissociation of HA Would the solution be conductive?Slide11: HA H+ A- Weak Acid HA H+ + A- At any one time, only a fraction of the molecules are dissociated.Strong and Weak Acids/Bases: Strong and Weak Acids/Bases Strong acids/bases – 100% dissociation into ions HCl NaOH HNO3 KOH H2SO4 Weak acids/bases – partial dissociation, both ions and molecules CH3COOH NH3 Slide13: pH 2 3 4 5 6 7 8 9 10 11 12 neutral @ 25oC (H+) = (OH-) distilled water acidic (H+) > (OH-) basic or alkaline (H+) < (OH-) natural waters pH = 6.5 - 8.5 normal rain (CO2) pH = 5.3 – 5.7 acid rain (NOx, SOx) pH of 4.2 - 4.4 in Washington DC area 0-14 scale for the chemists fish populations drop off pH < 6 and to zero pH < 5Slide14: You are here! http://nadp.sws.uiuc.edu/isopleths pH of Rainwater across United States in 2001 Why is the eastern US more acidic? air massesWhat is acid rain?: What is acid rain? CO2 (g) + H2O H2CO3 H+ + HCO3- Dissolved carbon dioxide lowers the pH Atmospheric pollutants from combustion NO, NO2 + H2O … HNO3 SO2, SO3 + H2O … H2SO4 both strong acids pH < 5.3Slide16: Behavior of oxides in water– Group A basic amphoteric acidic 3A 4A 5A 6A 7A 1A 2A 8A Group B basic: Na2O + H2O 2NaOH (O-2 + H2O 2OH-) acidic: CO2 + H2O H2CO3 Slide17: When life goes either way amphoteric (amphiprotic) substances HCO3- H2CO3 CO3-2 Acting like a base Acting like an acid accepts H+ donates H+Slide18: pH 1 2 3 4 5 6 8 9 10 11 The biological view in the human body gastric juice vaginal fluid urine saliva cerebrospinal fluid blood pancreatic juice bile acidic basic/alkaline 7 Tortora & Grabowski, Prin. of Anatomy & Physiology, 10th ed., Wiley (2003)Slide19: Does the pH influence the activity of an enzyme? Trypsin is a digestive enzyme. Where? Intestinal pH range 7.0-8.5Slide20: The amino acid glycine - amphoteric It’s an acid and a base! Loss of H+ Gain of H+ H2N-CH2-COOH H3N+-CH2-COOH H2N-CH2-COO- Chime structureSlide21: The amino acid glycine - Zwitterion formation Transfer of H+ from carboxylic acid group to amine group. H2N-CH2-COOH H3N+-CH2-COO- + - A dipolar ion forms. intramolecular acid-base reaction Chime structureSlide22: Show how water can be amphoteric. H2OSlide23: Dilution water (solvent) solute concentrated, Minitial diluted, Mfinal adding water lowers the solute concentration moles of solute remain constant Vinitial Vfinal molesinitial = molesfinal Mfinal x Vfinal = Minitial x VinitialSlide24: Titration Calculation HCl + NaOH NaCl + HOH at equivalence point: moleHCl = moleNaOH moles = M x VL Macid x Vinitial acid = Mbase x Vburet A way to analyze solutions! indicator