Acids and Bases

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