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