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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 H 2 gas React with bases to produce salts and water Conduct electric current. Bases Taste Bitter - PowerPoint PPT Presentation
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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