Name

Acids and DosesTextbook pages 220-233

Before You Read

Date Section

5.1Summary

Many acids and bases can be found in your home. Describe one acid and one base thatyou are familiar with. Record your answer in the lines below.

What are acids and bases?Many common pure substances can be classified accordingto whether they are acids or bases. Acids produce hydrogenions (Hf) and bases produce hydroxide ions (OH-) whendissolved in solution. The concentration of hydrogen ionsrefers to the number of hydrogen ions in a specific volumeof solution. Solutions with a high concentration of hydrogenions are highly acidic. Similarly, solutions with a highconcentration of hydroxide ions are highly basic. When anacidic solution is mixed with a basic solution, the solutionscan neutralize each other, which means that the acidic andbasic properties are in balance.

What is pH?Testing the pH of a solution is a way of measuring itsconcentration of hydrogen ions, H(aq). The pH scale is anumber scale that indicates how acidic or basic a solutionis. Acids have a pH below 7 and bases have a pH above 7.Neutral solutions have a pH of 7. On the pH scale, one unitof change represents a 10-fold change in the degree of acidityor basicity. For example, a two unit drop in pH is a 102 or100 times increase in acidity. 0

? Create a Quiz

After you have read thissection, create a five-question quiz on acids.Answer your questions untilyou get them all correct.

Reading CheckWhat is the pH of a neutralsolution?

What are pH indicators?pH indicators are chemicals that change colour dependingon the pH of a solution.

• Litmus paper can determine whether a solution is acidicor basic. Blue litmus paper turns red in an acidic solution(below pH 7). Red litmus paper changes to blue in abasic solution (above pH 7),

© 2008 McGraw-Hill Ryerson Limited Section 5.1 Acids and Bases • MHR 81

• A universal indicator contains a number of indicatorsthat turn different colours depending on the pH of thesolution.

0Reading Check • Phenolphthalein, bromothymol blue, indigo carmine,Provide the name of a methyl orange, and methyl red are other common pHcommon pH indicator, indicators. Each determines pH within a different range.

0A digital pH meter or pH computer probe that measuresthe electrical properties of a solution can also be used todetermine pH.

How are acids and bases named?Generally, the chemical formula for an acid starts withH (hydrogen) on the left hand side of the formula. Acidscan be named in several ways. Many compounds take onacidic properties only when mixed with water. If no state ofmatter is given, the name may be begin with hydrogen, asin hydrogen chloride (HC1). However, if the acid is shownas being aqueous (dissolved in water), a different name maybe used—one that ends in -ic acid, as in hydrochloric acid.Other acids that do not contain oxygen, such as hydrofluoricacid, HF(aq); nitric acid, HNO3(aq); and sulphuric acid,H2SO4(aq), also follow this naming system.Another naming system is followed when oxygen is

present in the formula. Names that begin with hydrogen andend with the suffix -ate (i.e., hydrogen carbonate,H2C03)can be changed by dropping “hydrogen” from the nameand changing the suffix to -ic acid (i.e., carbonic acid,H2CO3(aq)). When the name begins with hydrogen and endswith the suffix -ite (i.e., hydrogen suiphite,H2SO3), then thename can be changed to end with the suffix -ous acid (i.e.,sulphurous acid,H2S03(aq)).Bases generally have OH on the right hand side of their

chemical formulas. Common names of bases include sodiumhydroxide (NaOH) and magnesium hydroxide (Mg(OH)2).

Section

5.1Summary

continued

82 MHR • Section 5.1 Acids and Bases © 2008 McGraw-Hill Ryerson Limited

Name Date

What are the properties of acids and bases?

Mg(OH)9

Section

5.1Summary

continued

table belowSome of the properties of acids and bases are compared in the

/Property Acid Base

I Taste I • Acids taste sour. Lemons, I • Bases taste bitter. TheCAUTION: Never taste I limes, and vinegar are quinine in tonic water ischemicals in the laboratory. common examples. one example.

Touch • Many acids will burn • Bases feel slippery.CAUTION: Never touch your skin. Sulfuric acid

. . • Many bases will burnchemicals in the laboratory (battery acid) is one. . your skin. Sodiumwith your bare skin, example. hydroxide (lye) is one

j example.

I Indicator tests • Acids turn blue litmus • Bases turn red litmuspaper red. blue.

• Phenolphthalein is • Phenolphthalein iscolourless in an acidic colourless in slightlysolution. basic solutions and pink

in moderate to stronglybasic solutions.

Reaction with some • Acids corrode metals. • No reactionmetals, such asmagnesium or zinc

I Electrical conductivity ‘Conductive • Conductive!an71ethan7

Production of ions • Acids form hydrogen • Bases form hydroxide(H±) ions when (0H) ions whendissolved in solution. dissolved in solution.

—--------------,

What are some common acids and bases?

Formula Name Examples of usesCH3COOH ethanoic acid or acetic acid in vinegar

H2S04 sulphuric acid automobile batteriesNaOH sodium hydroxide drain and overn cleaners

magnesium hydroxide

HCI hydrochloric acid digestion in stomach

antacids

© 2008 McGraw-Hill Ryerson Limited Section 5.1 Acids and Bases • MHR 83

Name

SaltsTextbook pages 234-243

Date Section

5.2Summary

Before You ReadHow many different uses for salts can you name? Write your answers on the lines below.

What are salts?In chemistry, salts are a class of ionic compounds that canbe formed during the reaction of an acid and a base. A saltis made up of a positive ion from a base and a negative ionfrom an acid. An acid and a base react to form a salt andwater in a chemical reaction called a neutralization (acidbase) reaction. For example:

HC1 + NaOH -, NaCl + H20acid + base -+ salt + water ®Which other compounds react with acids to producesalts?Acids can also react with metals and carbonates to producesalts

Mark the Text

Identify ConceptsHighlight each question headin this section. Then use adifferent colour to highlightthe answers to the questions.

Reading CheckWhat is a salt?

1. Metals: When metals react with acids to produce a salt,they usually release hydrogen gas, as shown below.2HC1(aq) + Mg(s) - MgCl2(aq) +H2(g)

The most reactive metals are the alkali metals andalkaline earth metals, which appear on the extreme leftof the periodic table. Within these groups, the elements atthe bottom of the columns react the most vigorously.

2. Carbonates: Carbonates can also react with acidsto produce salts. Much of the carbon dioxide on thesurface of Earth is trapped in rocks, such as limestone,dolomite, and calcite, which contain carbonate ions. Whencarbonate rocks react with acids, such as those in acidprecipitation, the carbonates help to neutralize the acid.Sulphuric acid is one component of acid precipitation.

© 2008 McGraw-Hill Ryerson Umited Section 5.2 Salts • MHR 89

SectioiiName Date 5.2 L_—_______

continued

The chemical reaction between this acid and carbonatereleases carbon dioxide gas, as shown below.

H2S04+ CaCO3 -* CaSO4 +H20 + CO2

What are oxides?Reading Check An oxide is a chemical compound that includes at least one

Which type of oxide oxygen atom or ion along with one or more other elements.combines with water to Both metals and non-metals can form oxides.form a base? .1. Metal oxides: A metal oxide is a chemical compound that

contains a metal chemically combined with oxygen. Ametal oxide, such as sodium oxide, combines with waterto form a base (see below).

Na20(s) +H20(l) 4 2NaOH(aq)(a base)sodium hydroxide

The base can then react chemically with an acid to form asalt.

2. Non-metal oxides: A non-metal oxide is a chemicalcompound that contains a non-metal chemicallycombined with oxygen. A non-metal oxide, such ascarbon dioxide, combines with water to form an acid.

C02(g) + 1120(l) 4H2C03(aq)carbonic acid

This acid can react chemically with a base to form a salt.

90 MHR • Section 5.2 Salts © 2008 McGraw-Hill Ryerson Limited

Name

Organic CompoundsTextbook pages 244-251

Before You Read

Date Section

5.3Summary

What do you think of when you hear the term “organic”? Outline your thoughts in thelines below.

Make Flash Cards

Create flash cards to helpyou remember commonorganic compounds. Writethe name of the compoundon the front of the card andthe information you want torecall on the back.

What are organic compounds?Organic compounds are any compounds that contain carbon(with a few exceptions). All other compounds are referred toas inorganic compounds. In almost all organic compounds,carbon atoms are bonded to hydrogen atoms or otherelements that are near carbon in the periodic table, especiallynitrogen, oxygen, sulphur, phosphorus, and the halogens.Other elements, including metals and non-metals, may alsobe present.The carbon in organic compounds forms four bonds,

which enables it to form complex, branched-chain structures,ring structures, and even cage-like structures. Severaldifferent methods can be used to model these structures.These include the structural formula, the ball-and-stickmodel, and the space-filling model shown below.

CH4

molecular formula

Shows a single

I _- covalent bond —_

H-C-H

structural formula

space-filling model

ball-and-stick model

© 2008 McGraw-Hill Ryerson Limited Section 5.3 Organic Compounds • MHR 95

Name Date

To recognize a compound as organic, look for an indicationof the presence of carbon in its name, chemical formula, ordiagram. However, there are a few exceptions to this rule.Certain compounds that contain carbon are classified asinorganic carbon compounds. These include any compoundsthat contain carbonates, (i.e., CaCO3);carbides, (i.e., SiC);and oxides (i.e., C02, CO). 0

Section

5.3 :___continued

Reading CheckHow does an organiccompound differ from aninorganic compound?

What are some common organic compounds?Two common organic compounds are hydrocarbons andalcohols.

1. Hydrocarbons: A hydrocarbon is an organiccompound that contains only the elements carbon andhydrogen. The simplest of all organic compounds isthe hydrocarbon molecule called methane (CH4)whichconsists of a carbon atom bonded to four hydrogenatoms. Other hydrocarbons are formed by linking twoor more carbons together to make a chain. The firstfive hydrocarbons are given in the table below.

Molecular Structural Shortened Space-FillingFormula Formula Structural Formula Model

Common Uses

methane CH4 H CH4 • Natural gasH—C—H heaters

ethane C2H6 H H CH3CH3 • ManufacturingH—C—C—H plastic

propane C3H8 H H H CH3CH2CH3 • Camp fuel

butane C4H10 H H H H CH3CH2CH2CH3 • Hand-heldH——c—t—E—H lighters

pentane C5H12 H H H H H CH3CH2CH2CH2CH3 • Componentofgasoline

———

96 MHR • Section 5.3 Organic Compounds © 2008 McGraw-Hill Ryerson Limited

Section

5.3 F—continued

• Sterilizer• Cleaner

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Reading Check

Date

Provide the molecularformula for ethanol.

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2. Alcohols: An alcohol is one kind of organic compoundthat contains C, H, and 0 in a specific structure. Thetable below shows some common alcohols.

MolecularFormula

StructuralFormula

ShortenedStructural Formula

Space-FillingModel

Common Use

methanol 0140 I Cl-130H • SolventH—C--O—H

ethanol C2H60 HH CH3CH2OH • Fuel, H.—C—C.--O—H

HH I— ,— ————---- —

isopropyl C3H80 H I (CH3)CH2OHalcohol 9

H—C—C—C—-H1—

©2008 McGraw-Hill Ryerson Limited Section 5.3 Organic Compounds • MHR 97