Focus on California 8th Grade Physical Science Textbook Chapter 7 Acids, Bases, and Solutions

Chapter Acids , Bases , and Solutions ( Standards Preview I Bis Chemical reactions are in which atoms are ranged into different tions of molecules . As a basis for understanding this concept Students know ) include freezing and boiling , in which a material ( ha form with no reaction . Students know how to mine whether a solution a ( bask , or neutral Scientific progress is made by asking meaningful questions and conducting careful tions . As a basis for understanding this concept and addressing the content in the other three strands . students should their own questions and perform . Students will Distinguish between variable and controlled parameters in a test . Solutions metal are very 250

I Adds . uses . and Solutions What are some characteristics of acids and bases ?

Check What You Know Suppose you dissolve a teaspoon of salt in a glass of water . Is it possible to recover the salt from the water ?

Explain . 251 The images shown hen represent some of IM My in this manner . You can use this vocabulary skill to help you understand the meaning of some key terms in ( his chapter . Use Related Words You can expand your vocabulary by learning the related forms of a word . For example , the common verb to bake is related to the noun baker and the adjective baked . As you read this chapter . look for related forms of the verbs indicate , saturate , and suspend . I To show to point to saturate To fill up as much as is possible suspend To hang so as to allow free movement Something that shows or points Io The of holding as much as is possible suspension The condition of hanging or moving freely Serving as a sign showing saturated To be full to hold as much as is possible suspended Hanging so as to allow free movement

Chapter Vocabulary Section ! solution sol ute Section 7523 dilute solution ( solubility saturated unsaturated solution solution Section add ( Indicator base Section hydrogen ion ( hydroxide ion stale neutral Salt Science Vocabulary Visit Web Code ( hunter 25

. ii ea . i , i , Reading sum Create Outlines An outline shows the relationship between im ideas and supporting ideas An outline usually is set up like the one shown below . Roman numerals the main . Capital letters show the . Use the headings , Key Terms , and Key Concepts to help you ' what information to include in your outline Here is a sample for the beginning of Section We Understanding Solutions I . What . Is a A . A mixture with the same properties Subheading throughout that contains a solvent and at least . one solute . largest portion . substance dissolved In the solvent . Solutions with ' Solutions without contain solids , liquids . or 33526 . and Suspensions Apply It ! what are the two main topics in this outline ?

Compare the definition ot solvent in the outline with the definition on page 256 How are they different ?

In your notebook , complete the outline for Section As you read , write an outline to help you understand the among topics in the section .

Make Your Own Indicator As you learn about acids and bases In thus chapter , you can make your own solutions that let you is , basic , or neutral Su ( solutions change ( in an and or a base and are called . You ( an use your solutions to test for and bases among substances found your home . Your Goal To make a ( indicators from flowers , fruits . vegetables , or other common plant materials To complete the , you must make indicators that will turn colors and bases use your to test a number of ( your ( to a standard rank the tested based on their values follow the safety In A Plan It ! your about foods . Flowers , or other plant that have , deep colors about from and vegetables you may in a supermarket , These materials may make good ( for your .

Focus Students know physical pro ( esses freezing and hailing . in which a material es with no chemical reaction . What are the of solutions . and suspensions ?

what happens to the of a solute when a solution ( arms ?

How do affect the freezing point and boiling point of a solvent ?

Key solution I solvent I salute suspension 2550 Understanding Solutions A , Standards What Makes a Mixture a Solution ?

Put about 50 or 60 milliliters ofwater into a plastic ( up . Add a spoonful of pepper and stir well . To a similar amount at water in a second cup , add a spoonful of table salt . Stir well . Compare the appearance of the two mixtures . Think It Over Observing What is the between the two ?

What other mixtures have you seen that are similar to pepper and water ?

That are similar to table salt and You thirsty . so you drink it tall . cool glass of tap water . But exactly what is tap water ?

Tap is ! mixture of pure ( and variety of other . such as ride , and . as oxygen and . are also in tap water . The dissolved tap water its taste . What is a Solution ?

Tap water is one example of a mixture called a solution . A solution is uniform that contains at and at least one solute . The solvent is the part ola solution present in largest amount . It dissolves the other substances . The solute is th that is in solution in amount and is dissolved by the solvent . A solution has the same properties throughout . It contains solute particles ( or ions ) that are too small to see . one substance into another is an example of physical change . physical change . into a new . can often lit undone to recover the original . solvents have physical such as boiling and melting points . You can use these properties to recover the from the solvent . Suppose you dissolve salt in water . boiling , point than salt . If you boil salt water , the water will vaporize first . the salt )

Solutions with Water In many common solutions . the solvent is water . Sugar in water , for . is the starting solution for flavored soda water . Adding food coloring gives the drink ' I dioxide gas in the mixture produces soda . Water so many that Video Held Trig Acids . 3359 . and it is often called the solvent . Life depends on writer solutions . Nutrients used by plants are dissolved in waiter in the soil . Water it the solvent in blood . saliva . and tears . Solutions Without Water solutions are with other than miter , as you can see in Figure . For ex ple . is solution different liquid fuels . Same ( lull ( such air or brass . don ! have liquid to ( at all . A solution may he a , liquids , or solids . is essential 10 living things ?

Gas Examples oi ( Solutions Solvent Solution Flour Solutions can be formed from Gas Air ( oxygen and other gases in nitrogen ) Gas any combination of solids , Liquid Soda water ( carbon dioxide in water ) liquid Solid Solid Solid liquids , and gases . Liquid Antifreeze ( ethylene glycol in water ) Photos What are I the for liquid Dental filling ( silver in mercury ) Li id Ocean water ( sodium chloride and other compounds in water ) Sow Stainless steel ( chromium , nickel , and carbon in iron ) Salt water is a solution of sodium chloride and other compounds in water . ill ! The air in these gas bubbles is a solution of oxygen and other gases In nitrogen . Stainless steel is a solution of chromium , nickel . and carbon in iron . humor 257

Comparing Thru Mixtures Solutions are different from and suspensions , Interpreting Photographs In Colloid Fats and proteins in mill form globular particles that are big enough to scatter light , but are which mixture can you see too small to be seen . the . A Suspended whales of snow in water are easy to see . Solution In a solution of glass cleaner . particles are uniformly distributed and too small to scatter light . Activity Scattered Light . Pour 50 . of a mixture into a small , clean glass beaker . Four 50 . of a saltwater solution into another clean beaker that is about the same size . Compare the appearance of the two liquids . In a darkened room . shine a small flashlight through the side of the beaker that remains gelatin . Repeat this procedure with the saltwater solution . Compare the of the light inside the two beakers . What evidence tells you that gelatin is a colloid ?

nu BIO and Suspensions Not all mixtures are solutions . and suspensions mixtures that have properties than solutions . look al Figure . The glass cleaner is a solution . You can see through because light passes through them out being in all . Have you ever tried to look through a glass of milk ?

Milk is a colloid . A colloid is a mixture that contains small , particles that do not settle oul . are still too small to be seen easily , but are large enough to a light beam . Milk contains Fats and proteins that globular at . These scatter light in tions . making it impossible to see through a glass of milk . Fog is a colloid that consists of water droplets in air . Fog scatters the headlight beams of cars . reducing visibility for drivers . Gelatin . shaving cream . and whipped cream arr other examples of . Suspensions you did the Standards Warn ) you noticed that no matter how much you stir pepper and water , the two really to mix completely . When you stop ring , you can still see pepper on the . surface and collecting at the bottom of the cup . Pepper and water make a suspension . A suspension ( suh SPEN shun is El mixture in which particles can be seen and easily separated by settling or . A suspension does not have the same properties throughout . it contains visible that than the particles in solutions or . The snow globe in Figure is another of a suspension .

Particles in a Solution Why does salt seem to disappear when you mix it with water ?

If you had a microscope powerful enough to look at the particles . what would you see ?

When a solution forms , particles of the solvent surround and separate the particles of the solute . tonic and Molecular Compounds In solution Figure shows what happens when the ionic compound . salt . mixes with water . The positive and negative ions are to the polar water molecules . Water molecules surround each ion as the ions leave the surface of the compound . As each layer of the compound is exposed . more ions can dissolve . However . not every substance breaks into ions when it solves in water . A molecular , such as sugar , breaks up into individual neutral molecules . The polar water attract the slightly polar sugar molecules . This causes the sugar molecules to move away from each other . The covalent bonds within the molecules remain unbroken . and Conductivity Suppose you have a water tion . but you don ! know if the solute is salt or sugar . How could you find out ?

Think about what you learned about the electrical conductivity of compounds . A solution of ionic pounds in water conducts electric current . but a water solution of molecular compounds normally does not . You could test the electrical conductivity of the solution . If no ions are present ( as in a sugar solution ) current will not . train which kind of solution conducts an electric and current ?

Go Online Visit Web Flour salt in wear when an ionic compound . water molecules surround and separate the positive and negative Ions . Notice that the sodium ions attract the oxygen ends of the water molecules .

Designing Experiments How does the mass of a solute affect the boiling point of a given volume of water ?

Design an experiment using a solute . water , a balance , a hot plate , and a thermometer . What variables should remain in your experiment ?

What is the manipulated variable ?

What will be the responding variable ?

approval trom your teacher , do the experiment . The Effect oi Salt on Point Fresh water on the surface of a lake is frozen , Under similar conditions . salt water is not frozen . 260 Saltwater bay Effects of on Solvents , the freezing point of pun water is . and the boiling point is . The addition of to water changes these . lower the point and raise the boiling point of a solvent . Lower Freezing Points Pure ( is made only of that at . When liquid water . water join together to form crystals of ice . In salt solution , particles are in water when it . The particles it the ' to form crystals . The temperature must drop lower than for the solution to freeze . The presence of a solute lowers the point of water . Figure illustrates the particles in pun water and in solution .

Reviewing Key Concepts IQ Higher Boiling Points The directions for cooking pasta often advise adding salt to the water . Why ?

As the temperature of a liquid rises . the molecules gain energy and escape into the air . In pure water , all the molecules are water . But in a solution . some of the particles are water molecules and others are of solute . The water molecules need more energy to escape when a solute is present . The temperature must go higher than ) For water to boil . raise the boiling point of the solvent . Adding salt to the water decreases cooking time for the pasta because the water is hotter . Car manufacturers make use of the effects of to noun protect engines from heat and cold . The coolant in a car airing smug . ator is a solution of water and another liquid called antifreeze . This might ! their car tram overheating by using the proper coolant in the radiator . Relating Cause and ( Hen Explain how coolant work ( Often the antifreeze is ethylene glycol . The mixture of the two liquids has a higher boiling point and lower freezing point than water alone . This solution can absorb more of the heat given off by the running engine . This reduces the risk of age to the car from overheating . The freezing point of this solution is lower than the lowest temperature the car is likely to be exposed to . This reduces the risk of damage from ing in very cold weather . luring at ha alo in freeing or ve Ig er I point than pun water ?

USA , Assessment Section Vocabulary Skill use words Complete the sentence by using solute and correctly . It is a mixture that contains at least one El . Relating Cause and Effect is the temperature needed to tract ocean water lower than the temperature needed to freeze the surface of a freshwater lake ?

Applying Concepts Why does salt sprinkled , on is roads cause the ice to melt ?

I . Defining What 13 a solution ?

la . Comparing and Contrasting How are solutions from colloid and ?

Inferring Suppose you mix food coloring in water to make it blue . I lave you made a solution or at suspension ?

Explain . Reviewing What happens to the solute when solution ?

Sequencing Describe as at series of steps how salt in water a solution that can conduct electricity . Summarizing What effects do have on a and boiling ?

Passing through With a family member , mix together a spoonful each of sugar and pepper in about 100 of warm water in a plastic container . Pour the mixture through a coffee filter into a second container . Ask your family member what happened to the sugar . Let the water evaporate overnight . Describe the difference between a solution and a suspension . 251

09 , Students know processes including freezing and boiling , in which a material es farm with no chemical reaction . How is ( measured ?

Why in Identifying ?

What factors the solubility at a substance ?

Key Terms I dilute solution I concentrated solution solubility I saturated solution I unsaturated solution I solution Making Maple Syrup Concentration and Solubility Focus Standards Does It Dissolve ?

Put hall a spoonful of soap flakes into a small plastic ( up . Add about 50 of water and stir . Observe whetherthe soap dissolve . Clean out the ( up . Repeat the test for a few other solids and liquids provided by your teacher . Classify the items you tested into two groups those that dissolved easily and those that did not . Think It Over Drawing Conclusions Based on your observations . does the physical state ( solid or liquid ) of a substance affect whether or not it is able to dissolve in water ?

Explain . Have you syrup on your pancakes ?

You know that it made from the sap of maple trees . something that sweet ri made in tree ?

Well . not . Concentration You must collect gallons of maple sap to one gallon of syrup . The sap of ii maple tree and pancake syrup in their concentrations . That is . they in of ) in Al curtain amount of ( water ) You maple syrup by the water from the maple sap . By ing the water . you are left with It ' solution . Boiling sap

Changing Concentration A solution has a lot of solute dissolved in a certain amount of solvent . You can make a concentrated solution by adding more solute or removing solvent . For example . fruit juices are sometimes packaged as concentrates . which are concentrated solutions . In making the concentrate . water was removed from the natural juice . A dilute solution has only a little solute dissolved in a certain amount of solvent . You can make a dilute solution by increasing the amount of solvent in solution . When you make juice from concentrate . you add water . making a more dilute solution . Measuring Concentration You know that maple syrup is more concentrated than maple sap . But how could you the actual concentration of either solution ?

GTO measure . you compare the amount of solute to the total amount of solution . You might measure the mass of a solute or solvent in grams . Or you might measure the volume ofa solute or solvent in milliliters or liters . You can measure concentration as the percent of solute in solution by volume or mass . Now an you change the concentration of , solution ?

Solubility If a substance dissolves in water . you might ask . How much can dissolve ?

Suppose you add sugar to at glass of iced tea . is there a limit to how you can make the tea ?

The answer is yes . At the temperature of iced tea , several spoonfuls of sugar are about all you can add . At some point , no matter how much you stir the tea . no more sugar will dissolve . Solubility is a measure of how much solute can dissolve in a solvent at a given temperature . if you can continue to dissolve more solute , you still have an unsaturated solution . When you added so much solute that no more dis solves . you have a saturated solution . If you add more sugar to a saturated solution of iced tea . the extra sugar just settles to the bottom of the glass . Flour ! Sugar In Tea At some point . this boy will not be able to dissolve any more sugar in his tea . Concepts When the boy can not anymore sugar in his tea . what term describes the solution ?

Calculating a Concentration To calculate the tion of a solution , compare the amount of solute to the amount of solution and multiply by 100 percent . For example , if a solution contains lo grams of solute dissolved in 100 grams of solution . then its concentration can he reported as 10 percent . Practice Problem A solution contains 12 grams at solute dissolved in 36 grams of tion . What is the tion of the solution ?

Each compound listed in the table dissolves Solubility In 100 of Water at ) Carbon dioxide ( Baking soda ( Table salt ( Table sugar ( i no , It to ! total pressure in water . but in different amounts . Interpreting Tables which compound is the most soluble ?

Which is the least soluble ?

Predicting Make a saturated solution of baking soda in water . Add one small of baking soda to about 250 of cool water . Stir until the baking soda dissolves . adding baking soda until no more dissolves . Keep track of how much baking soda you use . Then predict what would happen if you used warm water instead . Make a plan to test your prediction . With approval from your teacher , carry out your plan . Did your results confirm your prediction ?

Explain , 2640 Working With Solubility The solubility of a substance tells you how much solute you can dissolve before at solution becomes saturated . For solids . solubility is given for a lar solvent ( such as water ) at a particular temperature . For gases . the pressure is also given . Look at the table in Figure . It compares the solubility of some familiar compounds . In this case . the solvent is water and the temperature is . From the table , you can see that grams of water will dissolve grams of baking soda . But the same mass of water will dissolve grams of table sugar ! Using Solubility Suppose you had a white powder . You ca tell for sure whether the white powder is table salt or sugar . How could you identify it ?

You could its ity in water at and compare the results to the data in Figure . can identify a substance by its solubility because it is a characteristic property of nutter . What does the of a substance tell you ?

Factors Affecting Solubility Which dissolves more sugar iced tea or hot tea ?

You have already read that there is a limit to solubility . An iced tea and sugar solution becomes saturated when no more sugar will solve . Yet a hot , st cup of same tea can dissolve much more sugar before the limit is reached . The of me change when conditions change . the solubility ofa substance include pressure , the type of so ! vent . and temperature .

Pressure increasing increases solubility of gases . Soda water contains dissolved carbon dioxide gas . To the carbon in soda . gas is added high . Opening the or can reduces the . The escaping gas the sound you hear . Scuba divers must be aware of the effect of pressure on gases . Air is about RU . from tanks of ( air . from air in their blood in ' amounts as ( This occurs because the pressure underwater increases with depth . return to too quickly . nitrogen come out of solution and block . Div double over in pain . which is why this condition is called bonds . Pressure ( lungs Opening a shaken bottle of soda Solvents Some solvents and are not , Have may 10 ?

you ever tried to mix vinegar . which is mostly water , and oil to di ' solution . salad ?

If you , you in ' how the ' quickly separates into layers after you stop shaking it , Oil and do not mix because water is a polar compound and oil is . Polar compounds and nonpolar compounds do not mix very well . For liquid solutions , the all how well solute solves , The like dissolves like gives you a clue to which are soluble in which solvents . and polar compounds usually in polar solvents . pounds do not usually dissolve in polar you work with . you know that you can use soap and water to i li up ( latex ) paints . Hut cleaning up paints may require a solvent . such as turpentine . lust after a little shaking later Solvents and Solubility Try as she might , this girl can not get all and vinegar to stay mixed . and polar compounds don ! form solutions with each other . Chapter 255

Reviewing Math Algebra and ! I Analyzing Data Solubility ot KNO , Temperature and Solubility The solubility of the ( potassium nitrate ( varies in water at different temperatures . Reading Graphs At which temperature shown in no the graph is KNO , least soluble in water ?

so . Reading Graphs Approximately what mass of , KNO , is needed to saturate a water solution at ?

30 . Calculating About how more soluble IS at 40 ( than at 20 ?

in . Interpreting Data Does solubility increase at the same rate with every 20 in temperature ?

Explain . 10 ID 60 30 Temperature ( Temperature For most solids . solubility as the temperature increases . That is why the temperature is reported when are listed . For . the solubility of table sugar in ) giants ol water changes from grains at to El grams at to 487 grants at lO ( looks use this increased solubility ol sugar when they as ' candy , fudge , or . nut , you start with a mixture of sugar . corn syrup . and . AI mom , not much sugar can in water The mixture must he heated until it to boil . Nuts and other ingredients are added while mixture is still hot . call for ( the exact can the result . cooks use a candy ' to . Unlike most solids . gases become less soluble in a liquid when the ' of the liquid goes up . For example . more carbon dioxide will in ( old than in hot Have you ever noticed that warm soda water tastes ?

Warm soda water contains less carbon dioxide gas . When you a warm water . dioxide from the soda water in amounts than soda water had been chilled . So if you soda water that very tizzy , open it when it cold ! 10 Temperature Changes Solubility Some hard randy is made by cooling a sugar water solution . Interpreting Photographs Why does sugar form when the solution is roofed ?

266 ii El 11 A Solution Dropping a of solute into a solution ( left ) causes the saline to immediately come out of solution ( renter ) Soon . the precipitation is complete ( right ) a solution can dissolve more solute than it can at cooler temperatures . solution cools slowly . sometimes the extra solute will remain dissolved . A solution has more dissolved solute than is by its solubility at the given temperature . Look at Figure 11 . When you drop a crystal of solute into at rated solution . the extra solute will come out of the solution . solubility at a gun Section Vocabulary Skill use Related wants Compare the meaning of the noun solution with the meaning of solubility How they similar ?

How are they different ?

Reviewing Key Concepts . Reviewing What is Describing What quantities are compared when the concentration of a solution is ?

Applying Solution A contains SI ! Solution ii contains gal sugar . Can you tell which solution has it higher sugar concentration ?

Explain . What is solubility ?

Explaining How can solubility help you identify at ) Calculating Look back at the table in . At . how many limes more soluble in water is sugar than salt ?

535 As temperature increases . whit happens to the For Links on Visit a . Listing What factors that affect III ! solubility ?

Summarizing How does temperature the solubility of must ?

Relating Cause and When you heat and Add sugar . all of the sugar dissolves . When you cool the solution . some sugar comes out of solution . Explain . Pi . Concentration What is the concentration of a solution that contains 45 grams of sugar in 500 grams at solution ?

Concentration How much sugar is dissolved in 500 grams oi a solution if the solution is 70 percent sugar by mass ?

257 Students know how to determine whether a is acidic . basic , or neutral . What are the properties acids and bases ?

Where are acids and bases commonly used Key Terms I and ' I indicator I base Describing Acids and Bases CA Standards Focus ! Standards What Colors Does Litmus Paper Turn ?

Use a plastic dropper to put a drop ol lemon JUICE on a clean piece of red litmus paper . Put another drop on a clean piece of blue litmus paper , Observe . Rinse your dropper with water . Then observe other substances in the same way . You might observe orange juice , ammonia cleaner . tap water . vinegar , and solutions or soap , baking soda , and table salt , Record all your observations . Wash your hands when you are finished . think It Over Classifying Group the substances based on how they make the litmus paper change color . What other properties do the items in each group have in common ?

Did you have an . an apple . or fruit for ) today ?

If so , an acid part of your meal . The last time you washed your hair . did you use shampoo ?

answer is yes . then you may haw . use products that acids and i ) In addition . the chemical of acids and . keep you alive ! What are acids and do they react , and what are their ?

Properties of Acids in In an acid . you can ( its . Acids arc cli properties include the kinds of they undergo . An acid tastes sour . reacts with als and . and turns blue litmus paper rod . acids you havi heard of are acid , nitric acid . sulfuric acid . carbonic acid . and acetic acid . Lemons are acidic

Sow list If you ever tasted it lemon . you had ! hand experience with the sour taste of acids . Can you think of other foods that sometimes taste sour . or tart ?

Citrus lemons . grapefruits , oranges . and acidic . They all contain citric acid . Other fruits ( cherries . tomatoes . apples ) and many other types of foods contain acids , too . Although sour taste is a of many acids . it is not one you should use to identify a compound as an acid . Scientists never taste chemicals in order to identify them . You should never taste it substance unless you know that it is safe to eat . Reactions with Metals Acids react with certain metals . such as magnesium . zinc . and iron . to produce hydrogen gas . When they react , the metals seem to disappear in the solution . This observation is one reason acids are described as corrosive , meaning they wear away other materials . The metal plate in Figure is being etched with acid . ing is one method of making printing plates that are then used to print works of art on paper . To make an etching . an artist first costs a metal plate with an wax . Then the design is cut into the beeswax with at sharp tool . exposing some of the metal . When the plate is treated with acid . the acid eats away the design in the exposed metal . The metal still covered with wax remains intact . Later . ink applied to the plate collects in the grooves made by the acid . The ink is transferred to the paper when the etching is printed . FIGURE with Add Metal etching uses the reaction of an acid with a metal . lines are cut in a wax coating on a plate . Here . acid eats away at the exposed zine metal , forming bubbles you can see In the up . Applying Concepts What gas forms in this reaction ?

ozu noun The Litmus test Litmus paper is an easy way to Identify quickly whether an unknown compound is an acid at a base . infecting What can you infer about a liquid that does not change the color of blue litmus paper ?

Acids tum blue litmus paper red . 170 Reactions With Acids also react with ate ions in a characteristic way . Recall that an ion is an atom or a group of atoms that has an electric charge . Carbonate ions contain carbon and oxygen atoms bonded together . They carry an overall negative charge ( One product of an reaction with is the gas carbon dioxide . Geologists , scientists who study Earth . use this property of acids to identify rocks containing certain types of limestone . Limestone is a compound that contains the carbonate ion . If a geologist pours dilute hydrochloric acid on a limestone rock . bubbles of carbon dioxide appear on the rock surface . Reactions With Indicators If you did the Standards . you used litmus paper to test several substances . Litmus is an example of an Indicator , compound that changes color when in contact with an acid or a base . Litmus is a kind of dye derived from plants called lichens ( LY ) mus paper is made by coating strips of paper with litmus . Look at Figure to see what happens to litmus paper as it is dipped in a solution containing acid . Acids turn blue litmus paper red . Vinegar . lemon juice . and other acids turn blue mus paper red . Sometimes chemists use other indicators to test for acids , but litmus is one of the easiest to use . i ! How Is ?

Bases turn red paper blue .

Properties of Bases Bases are another group ut that can be their properties ) A has tastes hitter . feels slippery . and turns red litmus paper blue . bases . und . Bitter Taste Bases taste hitter . The slightly bitter taste of water is caused by the bust quinine . Snaps . detergents taste hitter mu , they are suite to taste Yuu a ) knuw that it is tu eat . Slippery Feel Picture washing dog . As inn massage the soup into the dog fur , you notice that your eel pers This slippery is ' of But iust as you avoid it to identify it , yuu tu it . Strung can irritate or burn your skin . A safer way to identify haves is by their other properties . Reactions With Since litmus paper can be used to test . it till he used to test buses . tun . Look Figure 13 to see litmus paper as it is dipped in haste . Bases turn red paper . like acids . react with other lIl ( But paper gives it reliable . sale test . An easy way to litmus is to the letter in Bases turn litmus paper blue . an . What is one safe way In identity a base ! Foams Bases in Soaps you give a dog a sudsy bath . bases in the soap could make your hands feel slippery . Go , For Links on acids and bases Web Code Chapter 171

Flaunt Uses of Acids Acids are lound in vegetables and valuable products used in , in , Mom homes and industries . ohm use din , solutions of acids to ( lean brick and other surfaces Hardware stores sell muriatic id and Food ( hydrochloric ) acid . which is used to clean ' I od anyo and you eat are acid Acids and Industry ' and manufacturers depend on acids for many uses . Sulfuric acid . reacts with Tomatoes and ind Grill contain Folic acid , for Mam . healthy cell growth , I usury is in LEE i current . Nitric acid and phosphoric add are used to make fertilizers for crops and lawns . Uses of Acids and Bases Where can you find acids and bases ?

Almost You already learned that acids arc found in many fruits and foods . In fact . acids are vitamins . including ascorbic acid . or vitamin ( I , and acid . are in small amounts to normal growth and functioning of the body . Many cell processes also produce acids as waste products . For ple . lactic acid builds up in your muscles when you make them work hard . Manufacturers . farmers , and builders are only sonic people who depend on acids and bases in their work . Acids and bases have uses around the home and in industry . Look at Figure 15 and Figure la to learn about few of them . Many of the uses of bases take advantage of their ability to react with acids . What are adds ?

271 ' 15 loses in the Home USES Of Bases Ammonia are safe , The of bases make them 59 ' valuable raw materials for a range mu You ' oi products . ki mistake the drain cleaners . odor of household cleaning products made with Drain cleaners . contain sodium hydroxide ( lye ) I , Bases and Food Baking soda reacts with acids such as lemon juice and buttermilk to ( dioxide gas in baked goods . these gas bubbles , breads . biscuits . takes , and cookies would not be light and fluffy . Bases and Industry A Mortar and cement are manufactured using the bases oxide and hydroxide . Assessment um Making Judgments , il wise In wear the verb in ' a dictionary . How docs slum when in ii gnaw ?

knowing the meaning of help you the adjective ?

Reviewing Key Concepts Writing in Science a . Listing are our properties of acids ?

is ming can paper from me lab she ! Design . wanted poster describing properties of the at . i ' git , as one ( itt ingredients ?

Hub . Ti , i MINI I 11 three uses of is bug Aida . caution on your poster that warns people not , I . Making Generalizations are you ! mud my him , may likely in find acid and bum in yuur home should notify the chemistry lab .

determine whether a solution is acidic . basic . or neutral . What kinds of ions do acids and bases in water ?

What does tell you about a solution ?

What happens in a neutralization reaction ?

Key Terms hydrogen ion ( I ) I hydroxide ion ( OFF ) scale neutral neutralization salt 274 Acids and Bases in Solution Standards Students know how to ! What Can Cabbage Juice Tell You ?

Using a dropper , put drops of red cabbage juice into each of three separate plastic cups . Add 10 drops of lemon juice ( an acid ) to one cup . Add 10 drops of ammonia cleaner ( base ) to another . Keep the third cup for comparison . Record the colors you see . Now add ammonia . drop at a time , to the cup containing lemon juice . Keep adding ammonia until the color no longer changes . Record all color changes you see . Add lemon juice a drop at a time to the ammonia until the color no longer changes . Record the changes you see . Think It Over Forming Operational Definitions Based on your observations . what could you add to your definitions of acids and bases ?

A ' pours acid into it . she adds sodium hydroxide to the acid . The mixture looks the same . but the warm . it she tested the solution with mus paper , what color would the paper turn ?

Would you he if it did not change color at all ?

It exactly the right and cunt oi the acid and the base were mixed . the beaker would hold nothing but salt water ! How could these two harmful chemicals react to produce something to the much ?

In this section , you will the . Acids in Solution What do acids have in common ?

that each formula in the list ) lil ( in Figure begins with . The acids you will about in this section all produce one or more ions and negative ion in solution with water . A hydrogen ion ( is an atom of hydrogen that has lost its electron . The negative ion may be a nonmetal or polyatomic ion . ions are the key to the ' of acids .

from 17 1110 ! and 33505 adds ' and . Making all of the acid formula in the table have in add Potassium hydroxide ma Calcium hydroxide ' eaten ) add Aluminum hydroxide Al ( odd Ammonia Nit , Phosphoric acid Calcium oxide cao Acids in water solution separate into hydrogen ions ) and negative ions . In the case of hydrochloric acid , for ple , hydrogen ions and chloride ions form An produces hydrogen ions ( IV ) in water . These hydrogen ions cause the properties of acids . For instance . when you add acid to certain metals . hydrogen ions interact with the metal atoms . One product of the reaction is hydrogen gas ( Hydrogen ions also react with blue litmus paper , turning it red . That why acids turn litmus paper ned . Why do odds turn paper ?

Bases in Solution Look at the table in Figure 17 . Many of the bases are made of positive ions combined with hydroxide ions The hydroxide ion ( OIT ) is at negative ion . made of oxygen and hydrogen . When bases dissolve in water , the positive ions and hydroxide ions . Look at what happens to sodium hydroxide in water water Na OH Not all bases contain hydroxide ions . For example , the gas ammonia ( does not . But in solution , ammonia is a base that reacts with water to form hydroxide ions . nu , Notice that both reactions produce negative hydroxide ions in Computing laws the product . A has produces hydroxide ions ( OH ' in ?

535 ' water . Hydroxide ions are responsible for the bitter taste and ' feel or bases , and turn led litmus paper blue . China ?

0173 I ! Add in mi Stung Add Wont Add Strong acids and weak acids act ' in water . Hydrochloric acid ( left ) is a strong acid . Acetic acid . I . Chloride ion ( Hydrogen ion ( Acetic acid ( Acetate ion ( ia , In a solution of I In a solution of a strong acid . all the weal acid . fewer acid molecules molecules break up break up Into Ions Into Ions . Mic Activity Strength of Acids and Bases Acids and bases may be strong or weak . Strength refers to how . Select mat ' I A . sud , well an acid or a base produces ions in water . As shown in sod . Figure 19 , the molecules a strong acid react to form ions in tea , and antacids . If the solution . With zi weak acid . very few ions form in solution . At sample is solid . dissolve the same concentration . ii strong acid produces more hydrogen ' ions ( than a weak acid does . Examples of strong acids a ' include hydrochloric acid . sulfuric acid . and nitric acid . Most other acids . such as acetic acid . are weak acids . know mild with St ' sol ti wa I a . la ham strong acids . A strong base produces more ions ( Using a plum , than does an equal of a weak base . Ammonia is a of one Ly ?

01 ' sodium hydroxide . IS strong ) sample onto a fresh strip . at papa , Measuring Knowing the concentration of hydrogen the ( ole ! of the ions is the key to knowing how acidic or basic a solution is . To strip to the scale on the describe the of ions , chemists use ii numeric scale called . The sale is a range of values from to . 70 ' VOW It expresses the concentration of hydrogen ions in a solution . Figure 20 shows the scale and some common ' eL ' Notice that the most acidic are at the low end of the scale . A than is acidic . The most basic items are at the samples from lowest to . Did my mum high the scale . A higher is basic . If is , you the solution is neutral . That means its neither an acid nor a hose . Pure water has it . 176

GA low indicates that the concentration of hydrogen ions is big . In contrast , I high indicates that the concentration of hydrogen ions is low . If you keep these ideas in mind . you can make sense of how the scale works . You can the ofa solution using indicators . The student in Figure 20 is using paper . paper turns a color for each value . Matching the color of the paper with the colors on the test scale indicates how acidic or basic the solution is . You can also use an indicator solution to the of a solution . Some indicator solutions will change color over the entire scale . Other indicator solutions only change color within a range of approximately two units . Knowing the range over which this color change occurs gives you a rough estimate of . Most chemistry tories contain a meter . A meter is an electronic device that makes rapid . accurate measurements . Using Acids and Bases Safely People often say that a solution is weak when they mean it is dilute . This could be a dangerous mistake ! Even a dilute solution of chloric acid can eat a hole in your clothing . An equal acetic acid , however , will not . in order to handle acids and bases safely . you need to know both their strength and their concentration . How would a weak base differ from an ' equal concentration on strong base ?

Farms 20 The Sale The scale solutions as acidic ! basic paper turns a color for each value . Interpreting Diagrams Ila solution has a of , is It acidic or basic ?

Dix 117 ) 21 Neutralization When you mix a strong add with a certain amount of hydrogen ions and a strong base with an equal amount oi hydroxide ions , neutral solution results Diagrams What do the colors in each of the three rectangles represent ?

Visit Well Code 27 ! strong add will when mixed together . acidic and basic solutions product I solution ' A that is dour to neutral . solution Reactions The story at the start of this section describes a chemist who mixed hydrochloric acid with sodium hydroxide . She got a solution of table salt ( sodium chloride ) and water . Maori If you tested the of the mixture . it would be close to or neutral . A reaction between an acid and a base is called ( noo shun ) After neutralization . an mixture is less acidic or basic than either of the individual starting solutions . The depends on the identities , the volumes , and the of the reactants . If a small amount of strong base reacts with a much larger amount of strong acid . the solution will remain acidic . Look at Figure . A solution of a certain amount of hydrogen ions . A solution of strong base contains an equal amount ions . If you mix them together . a neutral solution results .

Products Salt may be the familiar name uf the you sprinkle on food . But to a chemist , the word refers to group of compounds . A salt is any ionic compound that can be from the neutralization of an acid with a base . A salt is made from the positive ion ola base and the tive ion ofan acid . look at the equation for the reaction of nitric acid with potassium hydroxide two , No One product of the reaction is water . The other product is potassium nitrate ( a In a neutralization reaction . an acid reacts with a base to produce a salt and water . Potassium nitrate is written in the equation as separate and , ions because it is soluble in water . salts , such as potassium nitrate , art soluble . Others form because they are insoluble look at the table in Figure 22 to see a list of some common salts and their formulas . what is a salt ?

Section Assessment Common Salts Sail Sodium chloride Uses Food flavoring food preservative Potassium iodide iodine calcium chloride ( act , for roads and walkways Potassium chloride Salt substitute in foods Found in limestone and seashell Calcium carbonate ( aw , Ammonium nitrate Fertilizer active ingredient in cold packs 11 Each salt listed in this table can be formed bythe reaction between an acid and a base . NA Reading Target Reading Skill ( rut Outlines Complete a . Reviewing What are the reactants your outline lot Strength of Acids and Blues . Use your outline to help answer the following questions . Reviewing Key Concepts LE El lE ' Identifying Which element is found in all the acids described in this section ?

Describing What kinds of ions do acids and bases form in water ?

Predicting What ions will the acid , form when dissolved in water ?

Reviewing What does a ' tell you ?

is . Comparing and Contrasting solution has at . would the solution contain more or fewer hydrogen ions I I than an equal volume of solution with a of ?

Making Generalizations Would a dilute solution of ( also ?

990 reaction ?

Explaining What happens in a ' reaction ?

Problem Solving What acid reacts with to produce the salt ?

With a family member , search your house and refrigerator for the items found on the scale shown in Figure 20 . Line up what you are able to find in order of increasing . Then ask your family member to guess why you ordered the substances in this way . Use the lineup to explain what means and how it is measured . 219

Consumer Lab The Antacid Test Problem which antacid neutralizes stomach acid with the smallest number of drops ?

Skills Focus designing experiments . interpreting data . measuring Materials plastic dropper small plastic cups dilute hydrochloric acid ( 50 methyl orange solution . liquid antacid , 30 . of each brand tested Procedure ' Using a plastic dropper , put 10 drops of hydrochloric acid ( into one cup . is corrosive . Rinse spills and splashes immediately with water . use another plastic dropper to put 10 drops of liquid antacid into another cup . In your notebook , make a data table like the one below . Record the colors oi the and the antacid . Data Table Color With Indicator . Add drops of methyl orange solution to each cup . Record the colors you see . Test each of the other antacids . Discard all the solutions and cups as directed by your teacher . Methyl orange is an indicator solution that changes color ata of about . Predict the color of the solution you expect to see when an antacid is added to a mixture of methyl orange and . Design a procedure for testing the reaction of each antacid with . Decide how many drops of acid and methyl orange you need to use each time . a plan for adding the antacid so that you can detect when a change occurs . Decide how much antacid to add each time and how to mix the solutions to be sure the indicator is giving accurate results . Make a second data table to record your observations . 10 . Carry out your procedure and record your results . 11 . Discard the solutions and cups as directed by your teacher . Rinse the plastic dropper thoroughly . 12 . Wash your hands thoroughly when done .

Analyze and conclude . Interpreting Data Do your observations sup . Communicating Write a brochure that explains to consumers what information they need to know in order to decide which brand of antacid is the best buy . Designing Experiments What is the function of the methyl orange solution ?

port your predictions from Step ?

Explain why or why not . why do you think antacids reduce stomach acid ?

Explain your answer , using the observations you made . Controlling Variables What variables are controlled ?

Why ?

What are the manipulated and responding variables ?

Measuring Which antacid neutralized the with the smallest number of drops ?

Give a possible explanation lo ! the difference . Design an Experiment A company that sells a liquid antacid claims that its product works faster than tablets to ize stomach a ( Design an experiment to pare how quickly liquid antacids and chewable antacid tablets neutralize hydrochloric acid , Obtain your teacher permission before carrying out your investigation . Calculating If you have the same ume ( number of drops ) of each acid , which one can neutralize the most acid ?

Drawing Conclusions Did your pro give results from which you could draw conclusions about which brand of antacid was most effective ?

Explain why or why not .

Study Guide Adds taste 00 ! turn blue litmus paper red . and produce hydrogen Ions ( in water . Bases taste bitter , tum ted litmus paper blue , and produce ions ( OH ) in want . Understanding Solutions Key Concepts Aid solution has satin lI . particle that are too small to ' A colloid than ( IlL ) Th ( still nu small to lie , art large enough In light . A suspension does not ' the same ' lli . I . larger than the in or . I solution . particles of solvent and of the mix boiling , point . Key Terms ! I Concentration and ty ( Key Concepts sis To til the ur tu of solution . You rain . because it is a . iu ' Factors that the solubility of a . type . and . Key Terms ' solution . 281 Describing Acids and Bases ( Key Concepts and mics sour , i ' with ( and , turns blur litmus . lime hitter . feels . litmus paper . and ) uses and in . Key Terms maid Acids and Bases in Solution ( Key Concepts 345 ! I acid produces hydrogen ions ' in water . A base IUH I in water . tells yuu the ( Ul is high , In contrast , high you that lie . ul mus is low . I , aii with base to produce . and water . Key Terms inn i scale neutral salt

Review and Assessment ' For Visit Web Code fa ) Target Reading Skill Create Outlines To help Section copy ( Impi ( Describing Adds and laser the outline by and details . It em to Key ( and Run with mam , II . Properties of bases Reviewing Key Terms Choose the letter ' the best answer . Complete the following sentences so that MINT . Sugar water an example ot a ' deaf ! Plain 19 KEY 797 i . A is null solution . I . in which more he given IV at in Pepper and water make suspension I An acid Ii that tastes soul , reacts MIN ?

with and . and ( Soup is an ! A base ( 10 . Litmus is an an indicator ' i . A that ( color il an acid is at . indicator . Product Label Suppose you are a marketing executive for a maple syrup company . Write a description of the main ingredients of maple I . A ion mad at and is i i an container . Use what you we learned about concentration to explain how dilute tree sap ' becomes sweet , thick syrup . an ni a . lieu ! mad . Adds , oases . and Solutions

Review and Assessment Checking Concepts 11 . can tell the II and a . 12 . Dust at twu ' it dilute and sugar miter . 13 . are . Predict two ) i ) juice that you would be able to . how an helps ! an acid and il base . 15 . Give an oi . value , 16 . What of acid and base can he used In the salt sodium nking ally 17 . Applying Concepts A mil diver can be hy the bends . him the effects on the is to this condition . 18 . Relating Cause and Effect If you lean glass up water on table , yuu may are tiny in the water , Explain what ( these bubbles to . 19 . Drawing Conclusions have two clear paper red and one turn red litmus paper blue . mix them and retest with litmus , mint changes occur . the reaction that place ! mind . 20 . Comparing and Contrasting the types particles in water of acid with those in a water solution Uld ) 21 . Problem Solving Fill in the ( in the . 22 . Predicting Whit inn are when the ( is in water ?

Ma 23 . a Concentration it you have gratin of ) percent miter . how much sugar is dissolved in the solution ?

24 . Calculating a Concentration and Walt ! is 23 percent alcohol . is the volume oi in 200 . til the ?

Applying Skills Use the diagram to answer Questions . The Inflow ' the ( i ( an arid irt it Willi ! Water Acid 91 ' 25 . Interpreting Diagrams How can tell that the 11 trunk inferring Which in the diagram represent ions ?

27 . Making Models ( is strung Mid . Make tu show the this ( in . 28 . Drawing ( of iLl with the pi I iii a weak acid of the . Standards Performance Assessment ! Fur . list the you tested in order front most acidic least acidic . Would you use the same iti did again ?

Explain .

Choose the letter of the best . A scientist observes that an unknown solution turns blue litmus red and reacts with zinc to produce hydrogen gas . The unknown solution is most likely A a colloid . an acid . it hue . a suspension . Which of the following values indicates a solution with the highest concentration of hydrogen ions ?

A pi ! I I 14 . A base is defined as if it has a value in the range of A . Dissolving salt in water is an example of a physical change because A neither ofthe substances changes into a new substance . I the salt can not be separated from the water . the water become saturated with salt . physical change occurs whenever a substance is mixed with water . Which of the following things could be used to determine whether a substance is an acid or a base ?

A paper I litmus paper meter all of the above Standards Practice i ' at use the graph below and your knowledge of science to answer Question . Solubility of Potassium Chloride ( too so an a so so an so I ' 20 to ) A student makes a saturated solution of and lot at . If the student leaves the solution and all of the water evaporates . how many grams of ( il will be left in the container ?

A it 32 10 . Which ofthe following is an example of base ?

A tomatoes lemons vitamin soap I . You have an unknown solution . You want to know whether the solution is an acid or a base . First list some of the known properties of acids and Then describe a method of determining whether the solution is an acid or a hast . Input ?

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