Chapter 9Chapter 9Acids and Bases Acids and Bases

VocabularyVocabulary Acid—a hydrogen containing compound Acid—a hydrogen containing compound

that ionizes in water to produce that ionizes in water to produce hydrogen ions and is a proton donorhydrogen ions and is a proton donor

Base—a hydroxide containing Base—a hydroxide containing compound that ionizes in water to compound that ionizes in water to produce hydroxide ions and is a proton produce hydroxide ions and is a proton acceptor.acceptor.

Indicator—compounds that show a Indicator—compounds that show a definite color change when mixed with definite color change when mixed with an acid or base.an acid or base.

Electrolytes—a substance whose water Electrolytes—a substance whose water solution conducts an electric current.solution conducts an electric current.

Emulsify—dissolves fats and oilsEmulsify—dissolves fats and oils Salt—compound formed from the positive Salt—compound formed from the positive

ion of a base and the negative ion of an ion of a base and the negative ion of an acid. The compound is neutral.acid. The compound is neutral.

Neutralization—the name of a reaction Neutralization—the name of a reaction between an acid and a base.between an acid and a base.

Insoluble—will not dissolve in water.Insoluble—will not dissolve in water.

Acids and Bases Around UsAcids and Bases Around Us Acids and bases are all around us every day.Acids and bases are all around us every day.

Acids are in aspirin, vitamin C, oranges, Acids are in aspirin, vitamin C, oranges, grapes, lemons, grapefruit, apples, milk, tea, grapes, lemons, grapefruit, apples, milk, tea, pickles, vinegar, and carbonated beveragespickles, vinegar, and carbonated beverages

Bases are in lye, milk of magnesia, Bases are in lye, milk of magnesia, deodorant, ammonia, and soaps.deodorant, ammonia, and soaps.

Acid is necessary for digestion and bases, Acid is necessary for digestion and bases, such as antacids help when our stomach such as antacids help when our stomach hurts.hurts.

Industry depends on acids and bases as Industry depends on acids and bases as well. Metals are cleaned with acids. Bases well. Metals are cleaned with acids. Bases are used for making fertilizer and synthetic are used for making fertilizer and synthetic fibers. Both are used to make medicine.fibers. Both are used to make medicine.

Turn to your partner and Turn to your partner and name two common things name two common things

in which you find acids in which you find acids and two common things and two common things in which you find bases.in which you find bases.

Properties of AcidsProperties of Acids Acids taste sour.Acids taste sour. Acids affect the color of indicators Litmus Acids affect the color of indicators Litmus

paper changes from blue to red.paper changes from blue to red. Acids react with metals for form HAcids react with metals for form H22 and a and a

metal compound. The acid corrodes the metal compound. The acid corrodes the metal and produces a residue.metal and produces a residue.

All acids contain hydrogen, but not All acids contain hydrogen, but not everything that contains hydrogen is an acid. everything that contains hydrogen is an acid. When an acid is mixed with water, acids When an acid is mixed with water, acids ionize to produce hydrogen ions (Hionize to produce hydrogen ions (H++). This ). This ion is rapidly surrounded by water to form a ion is rapidly surrounded by water to form a hydronium ion Hhydronium ion H33O.O.

Common AcidsCommon Acids Strong AcidsStrong Acids

Sulfuric Acid—HSulfuric Acid—H22SOSO44

Nitric Acid—HNONitric Acid—HNO33

Hydrochloric Acid—HClHydrochloric Acid—HCl Strong acids are good electrolytes.Strong acids are good electrolytes.

Weak AcidsWeak Acids Acetic Acid—HCAcetic Acid—HC22HH33OO22

Carbonic Acid HCarbonic Acid H22COCO33

Boric Acid—HBoric Acid—H33BOBO33

Weak acids are poor electrolytes.Weak acids are poor electrolytes.

Properties of BasesProperties of Bases Bases taste bitter.Bases taste bitter. Bases are slippery to the touch.Bases are slippery to the touch. Bases turn litmus paper from red to blue.Bases turn litmus paper from red to blue. Bases emulsifyBases emulsify All bases contain the hydroxide ion (OHAll bases contain the hydroxide ion (OH--).). When dissolved in water, bases produce When dissolved in water, bases produce

this ion. Because the hydroxide ion can this ion. Because the hydroxide ion can combine with the hydrogen ion and form combine with the hydrogen ion and form water, bases are referred to as proton water, bases are referred to as proton acceptors.acceptors.

Common BasesCommon Bases Strong BasesStrong Bases

Strong bases are good electrolytes.Strong bases are good electrolytes. Potassium hydroxide—KOHPotassium hydroxide—KOH Sodium hydroxide—NaOHSodium hydroxide—NaOH Calcium hydroxide—Ca(OH)Calcium hydroxide—Ca(OH)22

Weak BasesWeak Bases Weak bases are poor electrolytes.Weak bases are poor electrolytes. Ammonium hydroxide—NHAmmonium hydroxide—NH44OHOH

Aluminum hydroxide—Al(OH)Aluminum hydroxide—Al(OH)33

Turn to your partner and list Turn to your partner and list two characteristics of an two characteristics of an

acid and a base. Then try to acid and a base. Then try to name one acid and one name one acid and one

base.base.

Acids and Bases in Solution: Acids and Bases in Solution: SaltsSalts

To measure the acidity of a solution, the To measure the acidity of a solution, the pH scale is used. This measures the pH scale is used. This measures the concentration of Hconcentration of H33O (hydronium).O (hydronium).

pH is a scale from 0 – 14. Seven is pH is a scale from 0 – 14. Seven is neutral; 0 – 6 is acidic; 8 – 14 is basic.neutral; 0 – 6 is acidic; 8 – 14 is basic.

Strong acids have low pH values. Strong Strong acids have low pH values. Strong bases have high pH values.bases have high pH values.

Determining pHDetermining pH pH is determined by using an indicator.pH is determined by using an indicator.

Litmus Litmus PhenolphthaleinPhenolphthalein pH paperpH paper Methyl orangeMethyl orange Bromthymol blueBromthymol blue Red cabbage juiceRed cabbage juice Grape juiceGrape juice

IncidatorIncidator AcidAcid BaseBase

Litmus paperLitmus paper RedRed BlueBlue

PhenolphthaleinPhenolphthalein ColorlessColorless PinkPink

pH paperpH paper Red to pinkRed to pink Blue to greenBlue to green

Methyl orangeMethyl orange RedRed YellowYellow

Bromthymol blueBromthymol blue YellowYellow Blue Blue

Red cabbage Red cabbage PinkPink Blue to greenBlue to green

Grape juiceGrape juice PinkPink YellowYellow

Formation of SaltsFormation of Salts When acids react chemically with bases When acids react chemically with bases

they form salts. The process is called they form salts. The process is called neutralization.neutralization.

The reaction produces a salt and water.The reaction produces a salt and water. Many of the salts formed are insoluble.Many of the salts formed are insoluble. The insoluble substance that crystallizes The insoluble substance that crystallizes

is called a precipitate because they fall is called a precipitate because they fall out of the solution.out of the solution.

Example:Example: HCl + NaOH HCl + NaOH H H22O + NaClO + NaCl

Exercise your brain!!!Exercise your brain!!!

Write the chemical equation to Write the chemical equation to demonstrate the neutralization of sulfuric demonstrate the neutralization of sulfuric acid and sodium hydroxide.acid and sodium hydroxide.

Here is a hint: Here is a hint: Sulfuric acid is HSulfuric acid is H22SOSO44

Sodium hydroxide is NaOHSodium hydroxide is NaOH When you think you have it, come write it When you think you have it, come write it

on the board on the board