Acids and Bases
Chapters 14 and 15
Properties of Acids/Bases
• Acids– Sour Taste– Change the color of an
acid-base indicator– React with metals to
form H2 gas
– React with bases to produce salts and water
– Conduct electric current.
• Bases– Taste Bitter– Change the color of an
acid-base indicator– Feel Slippery– React with acids to
produce salts and water
– Conduct electric current
Examples of Common Acids/Bases
• Acids– Citric Acid (fruits)– Acetic Acid (vinegar)– Sulfuric Acid– Nitric Acid– Phosphoric Acid– Hydrochloric Acid
• Bases– Ammonia– Milk– General Cleaning (NaOH)– Soaps
Naming Acids
• Binary Acids- acid that contains only two different elements. Hydrogen and one more– Hydro____ic acid
• HCl= hydrochloric acid• HBr= hydrobromic acid
Naming Acids
• Oxyacid-an acid that is a compound of hydrogen, oxygen, and a third element– Look on your reaction foldable or your naming
charts.– We wrote this information down back in
October.
Arrhenius Acids and Bases
• Arrhenius Acid- a chemical compound that increases the concentration of the hydrogen ions, H+, in aqueous solutions.– Form H3O+
• Arrhenius Base- a substance that increases that the concentration of hydroxide ions, OH-, in aqueous solutions
Strength of Acids
• Strong: ionize 100% in water– Only 7 are Strong– All are strong electrolytes
• HI, HClO4, HBr, HCl, HClO3, H2SO4, HNO3
• Weak Acid: doesn’t ionize 100% in water– All of the other acids
Strength of Bases
• Strong Bases: dissociates 100%– Only 8– Strong electrolytes
• Ca(OH)2, Sr(OH)2, Ba(OH)2, NaOH, KOH, RbOH, CsOH, LiOH
• Weak Bases: doesn’t dissociate 100%– All of the others
Homework
• Page 491 Numbers 3, 5, 8-11– On 8-11 Name and Classify as strong/weak
Acid/Base Theories
• Bronsted-Lowry Acid- a molecule or ion that is a proton donor
• Bronsted-Lowry Base- a molecule or ion that is a proton acceptor
• Water can act as both an acid and a base
Bronsted-Lowry
• Conjugate Acid/Base Pairs• Acid to form conjugate base it looses an H• Base to form conjugate acid it gains an H
• Amphoteric-species that can react as either an acid or a base
Bronsted-Lowry
• Monoprotic Acid- an acid that can donate only one H+
• Polyporitc acid is an acid that can donate more than one H+ over a series of steps.
Strong Acid-Base Neutralization Reactions
• Strong Acid + Strong Base = Salt + water
• Look on page 492 Number 26
Concept of pH
• When water self ionizes it forms an equilibrium reaction.
• K is a constant that represents equilibrium• Kw= ionization constant of water• Kw= 1.0 X 10-14
• Kw=[H3O+][OH-] AKA: Ka and Kb
The pH Scale
• pH 0-14 This is based on powers of 10• <7 acid• >7 base• =7 neutral
Formulas
• pH + pOH=14
• pH= -log [H3O+]
• [H3O+]=10-pH
• pOH= -log [OH-]• [OH-]= 10-pOH
• Kw= [H3O+] [OH-]
Examples
• Determine the hydronium and hydroxide ion concentration in a solution that is 1E-4M HCl.
• 1E-3M HNO3
• 3.0E-2M NaOH
• 1.0 E-4 M Ca(OH)2
Examples
• Determine the pH of the following species– 1.0 E-3M HCl
– 1.0 E-5 M HNO3
– 1.0 E-4 M NaOH– 1.0 E-2 M KOH
– Show all ways to work these
Examples
• The pH of a solution is 5. What is the concentration of the hydronium ion?
• The pH of the solution is 12. What is the hydronium ion concentration?
• The pH is 1.5. Calculate the hydronium and hydroxide ion.
• The pH is 3.67 determine the hydronium and hydroxide ion.
Homework
• Page 523 Numbers 8-15, 16 a,b
Determining pH and Titrations
• Acid-Base indicators: compounds whose colors are sensitive to pH– Common indicators: methyl red, bromthymol
blue, methyl orange, bromphenol blue, phenolphthalein, phenol red
Determining pH and Titrations
• You can also use pH paper or a pH meter to give the pH of the solution without a color change.
• Talk about Titrations