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9-12 Summary of Net Ionic Equations 259

Na (aq) T Ci-(aq) + K (aq) .,. NO;, (aq) _. NA

The total Ionic equation 1s

Na (aq) + Cr(aq) +- ~(aq) + NOJ (aq)-->

Na+ (aq) + Cr (aq) + K' (aq) -t NO (aq)

You don't necessarily have a reaction every time you mix solutions of ionic compounds! There 1s no net ionic equation for this combination because there is no reaction.

Complete the Active Example.

I

You improved your skill at writing net ionic equations In gen­eral and understanding what happens when solutions are mixed and in which no reaction occurs in particular

What did you learn by working this Active Example?

I r 1ctice Exercu;e 9 18

Write the net ionic equation that represents what happens when solutions of sodium nitrate and ammonium sulfate are mixed.

DE summary of Net Ionic Equations Table 9-4 sum ma rite this chapter. The blue a rea is essentially the same as the last three rows of Table 8-3 in Section 8-10 (the table that sum ma ri ted writing conven­tional equations).

' " .. lurnlwyoftMtlonlo ........

Producls Rllcllnll Rllcllon TWPt (Netlllnlc)

Element + salt or 0~1dat1on Single-replacement Element -r salt Element .,. ion Element + strong reduction acid

Two salts or Salt + Prcc1p11lllion Double- Two suits Two ions mong acid or Suh rcplncemenl + hyd rox1de base

Strong acid + Molecule Double- Salt T H20 II + OH h)droxide base formation (H10). replacement

neu1ral11at1on

Weak acid ... \folecule Double- ah - H10 Weak acid + OH hydro;ude base formauon (11 ,0). replacement

ncutralizu11on

Strong acid T ltalt Molecu le Double- Salt + weak acid II + anion of of '"ea k acid formation (weak replacement weak acid

UOIU)

Strong acid .._ Unstable product Double- Sall -+ IJ,0 + CO, 11 · + co,2 carbom1Le or + decompOSILIOll replnceme111 + Salt + H20 T CO, II + l lCO, h)drogen carbonate decompo:.nion

Strong acid - Unlttable product Double- Sall + 11 ,0 ..- CO, II -r so11 ~ullite '" · dccompos1t1on replacement + Salt + IIP -.. COi II + II O, h)drogen sulfite decompos1t1on

Ammonium sail + .. llJOH" + Double- Salt + Nll 1 + 11 10 NII/ + OH hydroxide base decompos1t1on replacement +

decompo~1t1on

Producls (Nellanlct

Element T ion

Ionic prccip1LUtc

H20

H,O -r union from '' eak acid

Weak acid

H?O-+ CO H,O + CO,

H10 + S02 H:O + o,

H20 + NH1

260 Chapter 9 Chemical Change

Your Thinking .... ::a 0 .Q

~

Classification

r -- relationships among associated concepts when there IS a better way of organiz­~ f- \ Ing lhem. Chapter 9 presents a new way ot classifying chemical equations that .S Includes the Ideas from Chapter 8 and also moves beyond them. Table 9-4 Is

The classif1cat1on thinking skill calls on your ability to change the way you see

'{:. designed lo help you to reorganize your mental arrangement of the relationships among types of equations. Notice, In particular, how the equation types from Chapter 8 fit Into the new scheme

IN REVIEW

Sl!e 1!11! Clwpwr S11111111af1es sec11011 fol/01l'111f: Chap1er 22 for a summary !ISi of 1he cl10111er !:Oals a11d a s1m1111arr of rlll' ke.I' l'011rep1s a.v.wcta11•d ll'llh t!acl1 goal ri11.v11'er.v w Target Chel'k.v. Practice Exercises, Ca11t•ep1-Lmki11g E.wrcise.v, Bl11e-N11111hered Q11es1io11.v £.\ercl.te.1. m1// Pral1le111.r a111nt11r 111the1mil of the d111pter. Your i11.strnc1ur ll'ill ha~i· tilt' a111wers /o E1·eryduv Clwmistr}' Qtiick Qui: qm•sticm,1 a11d Bluck-Numbt•ri!il Qut•.1ti1111s, Exercise~. and Problem~

Key Terms Ma.vi o/ tlw ke,1 tl!rm.v and m11c11p1.1 1111tl 111t111y atltt'r.1 app11ar 111 //11.' Glrls.\UTI'. Usl! 1·1mr Glo.vsury reg11/ar'1

acid p. 234 molecular product p. 252 spectator ions p. 238 spectators p. 238 actMty series p. 243

com·entional equation p.138 electrodes p. 229

net ionic equation p. 238

electrolysis p. 2..10 ion-combination reaction p. 248 ions p. 238

neutral molecules p. 238 neutralization reaction p. 252

nonelcctrolyte p. 232

srrong acid p. 235 strong clectrolyte p. 232 total ionic equation p. 238 weak acid p. 236 precipitate p. 248

major species p. 235 minor species p. 235

precipitation reaction p. 248 senm common strong acids p. 237 solution p. 229

"eak electrolyte p . 232

Frequently Asked Questions Q: What sliaultl hi! !lie ftical poi11I f<>r my r(!vie11· <>[ 1his dwpter? A: Table 9-4 summariz.es this chapter. IL should be a focal pomt of your study of net ionic equations. The upper-left corner of' the table is taken from Table 8-3: it describes conven­tional equations. Be sure to :.ee lhe connection between tbese equations and the expanded Table 9-4. Q: What i.t rlie mcl.ff cririrn/ .\/(!pin the· procedun• for writing 11e1 irmir eq11a1io11.1 1/tat l .1/tmtld ftu:u.v 011 wltilt- tlofng 1/te l!fld-<J[­dwpter que.1·1 iu11s, exerci.ve.\, and pmblem.f? A: Ir a conventional equation, i11cl11tli11g Males, can be wriuen. ii can be converted into a net 1001c equation by the three steps discussed in Section 9-4. In order to write these three steps, you must understand bow to change a conventiona l equotion into a total ionic equation. This is the critical step in the procedure. The electrolyte-classirication exercise that follow~ will hclp you master this concept. Q: 11011 du I decide if there i.1 1w reuc·ti<J11 ttfter heing gfre11 palential reactants? A: Check the activiry series, check the solubil iry table or guidelines, or look for molecular products (water or a weak acid) to be sure there is a reaction.

Q: What are 1/w pitfull.1 ttJ m•oitl in tlii.1 chapter~ A: Several pit falls await you in this chapter. Be careful of these:

1. Not watching out for double reactions. A double­rcplacemcnt reaction can yield 111·0 non-ionic products.

2. Failing to recognize unsrnble products <H1C0 1• H2S01• or " N H40 H").

3. Incorrect or missing states of reactant:. and products. Many incorrect formulas arc written because students do not recognize the states of some species.

4. Failing to recognize weak acids as molecular products that tlo 1101separate1mo ions. This wins lhe title of .. mo t com mon error in writing ne1 ionic equu tions."

5. " Inventing'" diatomic ions becau.se there are two atoms of an clement in a compound. H2

1 is the mos! common error.

6. I nsuftlcicnt practice. Writing net ionic equations is a l1:arning-by-doing skill. Muking mistakes ant.I learning from those mistakes is the usual route to sw.:ccss. Students who complelc both steps bcforf! the exam are happier students.

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Concept-Linking Exercises Wrl/1•" briL'/tfl!srrip1io11 of Ille rclu1u111.fhlps 11111tmg lht>julltrn•ing gmup.•· of 1£'1'/llS or phrus£s. A11swus lu the Co11cep1-Li11k:111g Exerri.W.'.J ffre 1(11'1!11

111 1/w eml 11[ 1/ie 1 llllpter

I. Electrolyte. noneleclrolytc. strong electrolyte. weak electrolyte

Electrolyte-Classification Exercise A fl.ill you //eedfor 11'1'11111g 11e1 w11ir eq11a11t111.\ .mrre.rsjull)' is the abil­ity to id1m1ifJ tit< 11mjfJr vpt•<'ie.1 in 011 cu1w11111 .111/11ti1m. Ft1r each sulrue

ftir11111f11 (/11 uq11e1111.1 111/111i1111) wrlf/e11 he/ow, (u) dussijy It u.t u .~1rm1g eleL'Trol)'le, a ll'eak eleclf'oll'lt'. or o 110111.dl'rtrolyre. r b) tde111if.1• the

Formula

I. HI 2. NazS 3. C12H:u011

4. HNO! 5. HF 6. LiF

7. HC104

8. HOIOz 9. NH~N01

10. HC211101 11. HCl 12. C~H120•

Electrolyte Classlflcatlon

Strnng electrolyte Strong electrolyte

Major Species

W (aq), I (<tq) Na (aq), $? (aq>

r Small-Group Discussion Questions r

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Smalf-Gr1111p Di,\r11s,1il111 Qul!sti1111.1 uri•f<>r grm1p 11 or~ . either i11 da.v.~ or w1tll!r lftl! g11fdu11n 1>f 11 l1•utler tluring a tli.<t·1u.ri1111 Jtl•r/i1m.

~ \Draw particulate-level sketches of a strong electrolyte, a '- weak electrolyte, and a nonelcctrolytc dissolved m water.

Explain bow each sketch nts the corresponding definition. Describe the conductivity of each solution. Write the for­mulas of at least three substances that fil euch category.

2. Draw a particulace-level sketch of a tiny fraction of a grain of table salt dissoh ing in water. Start with separate salt and water, then show the salt uissolving, and finally, illustrate the salt water solution.

0oraw paruculate-levcl sketches of solutions of a strong '--' ucid and u weak ucid. Based on your sketches. how nrc the

terms strong and weak Ubed to differentiute betwei:n these two acid c.lassifications? How can you use symbols to illustrate the difference between chemical equations illus­trating the dissociation of strong und weak acids?

4. A sliver-white strip or 1inc is placed in a blue solution of copper( II ) nitrate. Describe the macroscopic changes that occur as the products of rhc reaccion form. Zinc ion is colorless in aqueous solution, and finely divided copper appears black when \\et. Draw a particulate-level sketch of this reaction. Explain ho\\ your macroscopic descrip­tion is related to your particulate-level sketch.

5. Gasoline is a mixture of many different compounds. It is maue by boiling and cooling crude oil to separate the

Small-Group Discussion Questions

2. Conventional equation. total ionic equation. net ionic equation. spectaLOr ion

261

3. Redox reaction. ion-cornbinution reaction. precipitation reaction. molecule-formution reuction. neutralization reaction

ma1or species i11 wfutwn; u11d (f) id1m1if.1 rhe minor ,tpt•rics in •ol111i1111 (if 1my). Tiu· fir.rt two row~ are C(llTIJllt'tetl t1.11'.n1mple.1 A11.rn·er.f uppl!(lr

u11/w e11tl of the dwpwr

Minor Species

f-n(aq) none

componen ts of crude oil into fraction!>, each of which represents a small range or boiling points. Small quanti­ties of add itives are mixed into the final product, which contains more thnn 150 different compounds. Major components include butane (CJHw). penrunc (C~H t?).

hcxune (C,.H14), heptane (C, H 1h)• toluene (C~J lsCH 1). and xylene (C6HtCz~). Write the equation for the complete oxi­dation of each of these components. Then write a procedure for writing and balancing hydrocarbon oxidation equations that could be used by a beginning chemistry stu<lent.

6. Cobalt(! I) chloride and sodium carbonate solutions are com­bined, forming a precipitate. Explain how you can detcnrunc the identny of Lhe precipitate. Dmw parttcttlatc-lcvcl sketches of the separated solutions. and then illustrate che chemical change that occurs when the solution:. are combined.

7. How are double-replacement molecule-formation reac­tions <ind double-replacement precipitation reactions similar? How arc Lhcy different'! Draw a particulate-lcvel sketch of the formation of water from the combination solutions of two soluble i01uc compow1ds. Compare U1is sketch with your sketch of the formation of a precipitate.

8. Copy Table 9-4 onto the board in your classroom. For each of the eight reaction type:.. give an example conven­tional, total ionic, and net ionic equation. Explain how each or your example reactions salisties the description in each of the six columns in Lhc table.

261 a Chapter 9 Chemical Change

Questions, Exercises, and Problems lnt1mu:1il'e 1·ersi1111s o.f these problems may be 11.uig111.>d by yc111r irrstruc­lor. Svlulit>tl.V for lrluc-1111111/i<·r, d '/llt'1f/11111 are at Jiii! t'nd of tlw clzapwr. Quc1>1iou.1 other than those in the General Q11csti1111s rtml More Cha/­l1!11gi11g Pmblem.1 st'rt/1111.r ure paired in L'o11sec111iv1J t1dd·l'l'l!ll 1111111her comh111a1w11.v: so/u11011sfor the odd-1111mbered questions ure ulsu ut the l!ml 11[ the clwpter

Many questimu i11 thi.i clmpter 11re written with the ass11111ptio11 that 1·011 ltm•e s1utlied C!topter 6 and ran ll'rile the reqwredfom111lasfrom tltl!ir r/iemiral names. If thlt is 11ot tlte case, we hm·e placed a list of oil d111mic11lfo rn111u1.1 needed to t11mvcr Chapter 9 questions 0111111 c11d of t/1e Questwns. Ext!rcises, and Problems

Section 9-1: Electrolytes and Solution Conductivity ~How does a weak elcctrolyle differ from a nonelectrolyte?

2. Solid A is a strong electrolyte, and solid Bis a nonelectro-,c-lyte. State how these two compounds differ.

l . How can it be that all soluble ionic compou nds are elec-'-- trolytes but soluble molecular compounds may or may not --. be electrolytes?

4. (:'ompare tbc passage of electricity through a wire and ~ ihrough a solution. Whal conclusion may you draw if a

liquid is able lo carry an electrical current?

Sections 9-2 and 9-3: Solutions of Ionic Compounds and Strong and Weak Acids

Q11tmitm.15 tl1r1111gh 12: Write rhe m11jnr species i11 the water .10/11tio11 of e111·h .111b.m1111:e givm. All ionic compmmds gi1·<•11 ure soluble. ,.. -

1 " · (NH4)JS04• MnCl1

6. Mg(N03)~ . FeCl3

7~ NiS04. KlPO~

8. HCN , NaN01- HC104 ,.--1). HNO,, HBr

10. HCI. HCH02• KJ

' Ill H1C4H404. HF

12. NaCIO~. HI. HC2H3~

Section 9-4: Net Ionic Equations: What They Are and How to Write Them

Q11es11011s 13 rliro11gh 18: For each reacticm descnbed. write t/11! net 1u11ir l!l/llOfiClll

f ll A zinc chloride solution is mixed with a sodium phos-\ - phate solution, forming a precipitate of solid zinc phos­

phate and a sodium chloride solution.

14. When aqueo us soluuons of nickel( II) chloride and ammonium phosphate are combined, solid nickel(ll ) phosphate and a solution of ammonium chloride are formed.

15. Solid iron metal is dropped into a solution of hydrochlo­ric acid. Hydrogen gas bubbles o ut, leaving a solution of iron( Ill ) chloride.

16. When solid nickel metal is put into an aqueous solution of copper(! I) sulfate, solid copper metal and a solution of nickel( II ) sulfate result.

17. A solution of potassium nitrate and a solid precipitate of silver phosphate form when aqueous solutions of silver nitrate and potassium phosphate arc mixed.

Aqueous solutions of silver nitrate and potassium phosphate are combined.

18. When aqueous sollllions of sodium nitrite and hydrobro­mic acid a re mixed, an aqueous solution of sodium bro­mide and nitrous acid results.

Section 9-5: Single-Replacement Oxidation­Reduction (Redox) Reactions

Q11estio11s 19 through 24. F()r t•ach pair of reacrtmts. 11•rite the 1101 io111c aq11a1io11for any si11gle-replacemam red ox reocrio11 thm may be pre­dirted b}' Tt1ble 9-l (S11ctio11 9-S). Jf 110 redo.A ret1r:tic111 orrnr.1, ll'fitll NR.

19. Cu(s) + Li1SO.(aq)

20. Sn(s) + Zn(NOJn(aq)

21. Ba(s) + HCl(aq)

22. Mg(s) + CuS04(aq)

23. Ni(s) + CaC12(aq)

24. Zn(s) + RN03(aq)

Section 9-6: Oxidation-Reduction Reactions of Some Common Organic Compounds

Q11cJ'tiu11s 25 thm11g/1 l8: IVl'itl' the eq1wtio11ft>r em:h r11t1rticm tle.tcrihed.

25. Propane. C3H8, a component of"bollled gas," is burned asa fuel in heating homes.

26. Butane. C~H10• is burned as lighter fluid in disposable lighters.

Butane is the fuel in disposable lighters.

J

2"' Ethanol. C2H\01 I. the alcohol in alcoholic beverages. 1s

oxidized.

28. Acetylene, C1H2• is burned in \\eldtng lorches.

Section 9-7: Double-Replacement Precipitation Reactions

Q11t'11ic111.1 ~9 tltro11glr 16. Fcir <'111 h f1Uir 11/ rt•11rtcmt.1 giw11, wrt11• tlt1• Ill'/ ICJnl( t'q11at1(111 fnr am pre11p11m1011 react10111hu1 mar ht· prt•tlu 11·d h.1 Tahle 9-J or Fi1:1m Y-16 S1·1 """ Y-7 /{1111 preripiw1i1111 n-111 "'"' 11/'C'llrl II,,,,. \ R.

21J. Pb(NO,h(aq) + K l(aqJ

30. Co<NO,h(aqJ + K ,POJ(aqJ

\I. KCIO)(aq} + Mg(NO.),(uq)

32. 1Ju(N0,)i(aq) ~ Fe2(S0Moql

u. Agt\0,(aq) T LiBr(aq)

34. NiBr2Caq) + KO HCaq)

~ ZnCl~(aq) + Na.S01(aq)

36. NaNO,(aqJ + Ba(Oll )i(aq)

\j \1

'\7 Write the net ionic equal ions for the precipital ion of ct1ch of lhc follO\\ ing in~olublc IOnic compounds from aqueous solutions: PbCO,: Ca(Ol f),,

38. Wri1c lhe ne1 ionic eq uu11ons fort he precipirnuon of each of the following in~oluble ionk compoundi. from aqueous solutions: lead( 11 ) sulfide. copper( 11 ) carbonate.

Section 9-8: Double-Replacement Molecule­Formation Reactions

Q1tt'\/W11.1)SI1hro11glr 44. F11r 1•ud1 pmr ti{ reactu/11.\ gil'e11 irrilt' tht' flt'/ ill11ir t!IJllU1iu11 ft1r tire 11wli'ntlt·-j11r111u111111 rl'Ul'ttrm that 11'/// ucrur.

19 NaN02(aq) + lll(aq)

40. K 0 2(aq) + HCl(aq)

41. KC1H~OJ(aq) + HCIO~(:HI)

42. NaOH(aqJ + lll(aqJ

. .n RbOll!aql + HF(aq)

44. HC2H,Oiaql ~ Bu(0H l2(aql

Section 9-9: Double-Replacement Reactions That Form Unstable Products

Q1mmu11s 45 thruugh 48 for 1m1 h pwr vi rt•a,'t1m1s 1111·e11, 11·ri11 the""' imrir l!q11atl1111fl1r thl' rM1·1/o11 f /111111>/I/ t11'rt1r.

4'\ MgC0 3(aq) + HCl(aq)

46. 1 ICl(aq) + CaS01( )

.a Na2S0 3(aq) ,. llCI01<aq)

48. < 11~1iso .. caqJ + NaOll(aqJ

Section 9-12: Summary of Net Jonie Equations

Tiit• rt•m11ini11R q111•111<1111 mdudl! 111/ /\'pt•.1 ti} rl't1t'ti1111,1 di.\n1.1It'd111

1hl.1 dwptl'r Use· the lll'//1'111 .wmw 1111tl .\1Jltthlli11 1:111dc/i11es 111p11·tlii1

ll'hellwr rt!dlJ.\' IH 11rt•cipl1t1li1m rc•11rti11111 will lllkl' 11l11rt!. fj 11 re11/'/lt111 will It/I..( 11/atl', ll'ri/I' tin 11e11<11111· 1·11111111m1: ii 11111 ll'rill' N R.

Questions, Exercises, and Problems 261b

4'), Banum chloride and 'odium sullitc soluuons arc com­bined in an oxygen-free atmosphere. (Sulfitcs folio\\ the s11 me solubilny gl11dclincs u~ sulfates.)

SO. Aqueoui. ~olut1onb of nickel( II ) chloride and potassium hydroxide <ire added together

Solid nickel(ll) hydroxide precipitates

from solution.

Aqueous olut1on~ of 1ron(1 11 ) sulfate and cobalt( 11 ) nitrate are combined

52. Copper(JI) ~ulfatc and sodium h)dro:ude solullon~ arc combined

!'' Bubbles appear <I'> hydrochloric acid is poured onto solid magnesium curbonute

54. A piece of solid nickel metal 1s put into an aqueous i.olu­tion of lead(ll ) nitrate.

"!' Nitric acid appcurs to "dbsolve" solid lead( I I) hydroxide.

56. Solution~ ofhydrobrom1c acid and potassium carbonule are combined

~., Liquid methanol. C l 110 11. ' 'burned

58. Aqueous soluuons of ~odium hydroxide and hydrochloric acid a.re combrncd

Sii Benzoic acid. I IC 11\0 ,(:.J. 1s neutralized b) sodium hydroxide solulion.

60. Aq ueous solutions of sod ium hyd roxide and potuss1um mtrnte are combined

261 c Chapter 9 Chemical Change

fer. Aluminum is placed into hydrochloric acid. General Questions 7i'):>islinguish precisely, and in sclentilic terms. the

differences among items in each of the following p<tirs or groups: a) Strong electrolyte. weak electrolyte b) Elect rolyt c, nonelccLrolyle

__£l_§lrong acid, weak acid d) Coaventionul. Lota! ionic. and net ionic equations e) Burn, oxidize r) Ion-combination. precipitation, and molecule­

formation reaclions g) Molecule-formation and neutralization reactions h) Acid. base. saJt

c.80. Classify each of the following statements as true or folse: a) The solution of a weak electrolyte is a poor conductor

of electricity.

Aluminum in a hydrochloric acid solution.

62. A piece of solid copper metal is put in lo an aqueous solution oflead(ll) nilrate.

63. Hydrochloric acid is poured imo a solution of sodium hydrogen sulfite.

64. Aqueous solutions of sodium cyanide (cyanide ion. CN ) and hydrobromic acid are mixed.

65. Solutions of magnesium sulfate and ammonium bromide are combined.

66. Aqueous solutions of sodium hydroxide and ammonium iodide a re combined.

I 61. Magnesium ribbon is placed in hydrochloric acid. ...... 68. Aqueous solutions of barium hydroxide and calcium

iodide a re combined.

69. Solid nickel(IT) hydroxide is apparently readiJy ··dissolved- by hydrobromic acid.

70. A piece or solid lead metal 1s put into an aqueous solution of nitric acid

71. Sodium nuoride soluLion is poured 1mo nitric acid.

72. NiLric acid and solid manganese( LI) hydroxide arc combined.

73.. Silver wire is dropped into hydrochloric acid.

74. Aqueous solulions of silver nit rate and nickel( II ) bromide are combined .

.&. When solid lith1t1m is added to water, hydrogen is released.

76. Nitric acid and solid calcium su lfite are combined. (Su Hites follow the same solubility guidelines as sulfates.}

Aluminum shavings are dropped into a solu11on of copper(ll) Llilrulc.

78. Aqueous solulious of hydrofluoric acid and potassium hydroxide are combined.

b) Ions must be present if a solution conducts electricity. c) Ions are lhc major species in a solulion ofa soluble

ionic compound. d) There are no ions present in the solution of a weak acid e) Only seven "imponam" acids are weak. r) Hydrofluoric acid, which is used to etch glass, is a --strong acid. g) Spectators are included in a net ionic equation. h) A net iolllc equation for a reaction between an element

and an ion is the equation for a single-replacement rcdox reaction.

1) A compound that 1s insoluble forms a precipitate when its ions ure combined.

j) Precipitation and molecule-formation reactions are both ion-combination reactions having double­replacemem conventional equations.

k) Neulralitation is a special case ofa molecu le­formntion reaction.

I) One product of a molecule-formation reaction is a strong acid.

m) Ammonium hydroxide is a possible product of a molecule-formation reaction.

n) Carbon ts changed Lo carbon dioxide when a carbon· contai1ling compound burns completely.

Formulas

Tlwst> fi1rmu/11s url! pnmtletl 111 t'JJ•'I! vu11 ari• .wulymg Clwpll!r 9 bt'f Prc ya11 s1ud; Chapter 6. You sl11mld 1101 u.1e t/11.1 list 1111/ess _ro11r i11s1r11c1or /ia.f 1101 J'l!I al:.igm!d Clwpter6 or ntht•rwi:.I! imlirntetl 1/1111 l 'fllf m111 I/fl' tin /lw,

13. ZnCli. Na,POJ. Zn,IP04)i. NaCl

14. NiCJ2• (NH4hPOJ, 1 i,( P0 4)z. N H.iCl

15. Fe, J-ICI, H!, FcCl1

16. Ni. CuSO.i, Cu, NiSO~

17. I l2C20~. NaCl. Na2C20~, I !Cl

18. NaNOi. HBr. NaBr. HN01

38. PbS. CuCO,

_,

J

r

r

r

r

r

r

r

r

r

r

r

r

r

49. BaCI.. l\a,SO,

so. /\iCl2• KOH

51. Fe~(S0Jh. Co( NO,),

52. CuS04. NaOl 1

53. llCI. MgC03

54. 1\1, Pb!NO, b

55. 1 INO,. Pb!OH h 56. llBr. K,CO

58. "1a0LL UC!

59. \laOll

60. NaOH. KN01

61. Al. HCI

62. Cu. Pb( 01h

63. llCI. Na HSO,

64. 'iaCN. HBr

Answer to Target Check I. Pb a \\.Cak electrolyte hccuuse its solution b a poor con­

ductor. Thi\ 1nd1catc~ the presence of ion!. but in relatively lo'' concentration G is a i>trong elcctrolyte because its

Answers to Practice Exercises I. Ba(CIO,h(s)- Bd' (a4) ~ 2 CI03 (aq). Col1(s)-Co~• (uq) +

21 (aq): Mg(N01).(s)-+ Mg (uq) + 2 NOi (aq)

2. N1Cl1: Ni1•1aqJ -t 2 Cl (aql: Li2CO,: 2 Li'Caql i" C0,1 laq): Pb!NO,i,. Pb' (Uq) + 2 N02 (aq); (N I lt>iP04:

J N f-14 (aq) + PO~' (11q)

3. llC'I: H (aq) I Cl (oq): 11 ,S: H,S(aq): llCI04: ll ' (oq) -1 CIO~ (aqt HCIO: 1 ICIOlaq)

4. Al( 0 1htaqJ + '\ NuOHCaq 1-+ AICOHh(s) + 3 Nul\0,(uq) Al (aql + 3 NO, (aq) + 3 Na (aq) + 3 Oil (aq)-+

Al<OHh(sJ ... 3 l\a (aq) + 3 NO, Caq) ·\I- (aql + 3 OH faq)-AlCOHhM

S. Znts) T 2 llClcnqJ-11 (g) + lnCl1(:1q)

Ln(s) + 1 11 !aql 1- 2 Cl (aq)-+ ll_(g_l + Zn''<aq) + 2 Cl (uq)

Z.n(S} + 2 1-1 (Uq)-+ 11,(g) + ZnH (aq)

6. Cl1(g) + 2 Na Br(aq)- Br2C() + 2 NaCl(aq) Cl2(g) + 2 Na (aq) + 2 Br (aq)- Br1(() + 2 Na~(aq) +

2 o -caql Cl,(gl + 1 Br (aq ) -+ Br.(() 2 Cl (aq)

7. Ba(sl + 2 llOH<( l - Ba(Ol I Haq l + H2(g) Ba(s) + 2 1110((>- Ba '{aq) .,.. 2 OW (aq) + H2(g)

8. r·e(s) + CuS04Caq l - C'u(s) + FeSO~(aq) Fc(s) + Cu- (aq l + SO 1 (uq)-+ Cu(s) + Fe2 (aq) +

so ,1 (aq) Fc(s) + Cu1 (aq)- Cu(sl + J·c2 (aq)

Answers to Practice Exercises 261 d

65. MgSOJ, N HJ Br

66. NaOH. N H)

67. Mg. HCI

68. BalOH)2. Ca li

69. NitOHh, HBr

70. Pb, H N01

71. NaF, HN01

72. HNO,. Mn<OHh

73. Ag, HCI

74. AgNO,. NiBr,

75. Li. H~O. H2

76. HN03• CaS01

77. Al.Cu(N01h 78. HF. KOii

solulion is a good conuuctor. The solution contains ions in relatively high conce111ra11on. is a nonclcctrolytc because ll docs not comlucl. lts solulion co11111ins no ions.

9. C H,C H10 H(() + 3 O,(gl - · 2 C'02(g) T 3 H10(l)

10. Pb(NO,h(aq) -r 2 KICaql- Pbl21s) -,-1 K 0 1(<1q)

PbH (aq) + 2 NO, (aq) t 2 K (aq) + 2 I (aq)-+ Pbl2(:>) + 2 K ' (aq) + 2 NO, (uq)

Pb2~(aq) + 2 T (aq)-+ Pbl1(s)

11. Ni Br2(aq) + (NH~hSO,(uq)-+ NiS03(s) + 2 N I l~Br(uq) Ni2~(aq) + 2 Br (aq) + 2 N l VCaq) + SO/ (aql ­

NiS03Csl + 2 NI '~ (uq) t 2 Bnaq) Ni2 (aq) + SO,' (aq)-+ NiS01(s)

12. AIBr3(aq) + J Na F(aq)-+ Alf1(s) + 3 NaBr(aq) Al ' (aq) + 3 Br (uql -t ~Na (uq) + 3 r caql-AH 1(s) +

3 Na (aq) + 3 Br (aq) Al 1 (aq) + 3 r (aq)-+ Alf1(s)

l3. 2 llBr(aq) + Bu(01l)i(aq)-2 110H(l ) + BaBr1(aq) 1 H (aq) + 1 Br (aq) + Ba2 (uq) + 2 OH (aq)-+

2 llOH(t) + Ba1 (aq) + 2 Br (aq) 2 H (aq1 t 2 OH (uq)-t2. 1120C( ) 1-1 (aq) + OH (aq)- 11 Otl}

14. I ll(aq) + NaF(aq)-+ llF(aq) + Nal(aq) H (aq) + J (aq) + Na (aq) + rcaq)- HF(aq) +

Na (aq) + I (aq) ll (aq) + r (aq)-+ Ill (aq)

15. HCIO(aqJ 1- KOll(aq)-+ 110 1 l(l) + KCJO(aq) llCIO(aq) r K (uq) -t 0 11 (aqJ- HOl l{l ) i" K 1 (aq) +­

CIO (aq) l-ICIO(uq) + 01 1 (uq)-+ 1101 l(l ) + c10- caq)

261 e Chapter 9 Chemical Change

.16. NH4 NO,(aq) + NaOH(aq)-> NH,(aq) T H20(f) + NaN01(aq)

NH.i (aq) + NO:i- (aq) -1- Nnaq) +OH (aq)- NH3(aq) + H~O(f) -1- Na- (aq) + N01 (aq)

NH~ +(aq) +OH (aq)-+ NH,(aq) -'- H10(()

17. 2 HNO\(aq) + NiC01Cs)- H~O(C}-'- CO~(g) + Ni(N01h(aq)

2 W(aq) + 2 No\- (aq)-'- NiCO,Csl__,. H10(() + C01(g) + Ni1 (aq) + l NO, (aq)

2 W(aq) + NiCO,(sl- H20(l'l + C01<gl + Ni21(aql

18. 2 NaN03(aq) + (NHJbSO.i(aq)_. Na2SO~(aq) + 2 NI l4N01laq)

'.! Na ' (aq) + 2NO,-(aq) + 1 Nll/ (aq) + SOi (uq)-+ 2 Nu ~(nql + SO/ (aql + 2 NH4

1(aq) + 2 NO, foq) 2 Na; (aq) + 1 NO~ Caq) ..c. 2 N H4 ' (aq) +SO/ Caq)- NR

Answers to Concept-Linking Exercises You mor ""''" fo1111d mon· rdt11w11.vl1ips ot rl!/01in11,hfp.< orlwr t/1011 the fllll!.I gfre11i111he.\I!1111.111 er.1

I. An electrolyte is a substance Lhat. \\hen dissolved. yields a solution that conducts electricity. A nonelectrolytc yields a solution 1ha1 does not conduct electric11y. The tenns l!ll!Nrolp1l' and nonclec1rolrte also refer to solutions or dissolved substances. A strong electrolyte i~ a substance that form~ a solution that is a good conductor or electric­ity. A weak electrolyte conduct:. electricity but does so poorly.

2. A conventional equation show the complete formulas of the compounds and elements in a chemical reaction. Sub­srnnces that exist as ions in wacer soluuons arc not shown in Lhcir ionic form, but rather as the hypothetical unit particle represented by the formula. A total ionic equa­tion replacei, the formulas of the dissolved substances with the major species in solution. anll il includes specta­tor ions-lhose that experience no chemical change. The

net ionic equation is written by removing U1e spectators from the: total ionic equation. leaving on ly the species that undergo a chemical change.

J . A rcdox reaction is an electron-trnnsfcr reaction. Electrons arc transferred from one reacLing species to another. An uncombined elemem appears to replace another clemen t in a compound to yield a single-replace­ment equution. In ion-combination reaction:.. the cation from one reactant compound combines with the anion from another. T hese reactions have double-replacement equations. A precipitation reaction ii. an ion-combina­tion reac11on that yields an insoluble ionic compound. A molecule-formation reaction 1s an ion-combrnauon reacuon that yields u molecular product, usually water or a weak acid. If the product of an ion-combination reaction is water. fonned b; the reaction or an acid and a hydroxide base. the reaction is <1 ncutrali1.ation reacuon.

Answers to Electrolyte-Classification Exercise

Formula Elactrofyte Classification Major Species Minor Species•

I. HI Strong electrolyte W (aq}, r(aq) lll(aqJ 2. a1S Strong electrolyte Na-(aq), S2-(aqJ none 3. C12H~011 Nonelcctrolytc C011 ~1011laq) none

4. llN02 Weak elecu-olytc 1 INOz(aq) 1r•raq). NO, <nq) 5. HF Wea k electrolyte Hflaq l I r'"(aq). r (aq I 6. LiF SLrong elect roly le Li'(aq). r(aq) none

7. 1-lCIOJ Strong elecirolyte II (uql. Cl04 - (aq) ITCl0 1(aq) 8. llCH0 1 Weak electrolyte llCHO~caq) 1naq). Cl 10. (aqJ 9. H4N03 Strong electrolyte N 114 1uq ). NO.i (uq l none

10. 11C1ll ,Oz Weak electroly te llC H ,02(nql H+(aq). C.H,02 laq)

11. HCI Strong electrolyte Wcaq). Cl (aqJ HCl!aq) 12. C6H1201. Nonelectrolyte Ci.H1206(uqJ none

•No ionic compound is complclcl~ in~olt1ble in wati:r. There ure. in fuel. very ~mull conccnlnllion~ of culcium and carbonate ions 111 sol1111on m 1hc presence of solid culcium curbonutc und very small conccntmtions of ;iluminum und phosphute ionb m solution when that ~olid 1~ placed in \\Iller. AJditionall~. th1:re are very small concentrations or hydrogen antl hydroxide ions prcsenL m w:JLcr N Un) w1Ltcr ~oluuon.

-.../

r Answers to Blue-Numbered Questions, Exercises, and Problems 261f

r Answers to Blue-Numbered Questions, Exercises, and Problems r

I. Solutions of weak electrolytes conduct electricity poorly 37. Pb!-(aq) + Co/-(aq)-+ PbC03(s): Ca11 (uq J + because only a small quantity ofions forms when t11e elec- 2 0 1-naq) - CalOH)2(SJ trolyte dL~solves. Soluuons of nonelecuolytcs do not conduct 39. W(aq) + Noi-(aq)-+ HNOz(aq)

r elecmcity because essentially no ions exist in the solution. 41. H '{nq) + CJHp 3- (aq) -. HC3Hs0 ,(aq)

3. The movement of ions ma kes up an electric current in

r solution. Soluble molecular compounds are generally ncu- 43. OW(aq) + HF(aq)- H!O(f) + r(UQJ

tral and are usually nonelectrolytes. Some molecular com- 45. 2 W (aq) +CO/ (nqJ-+ H10(CJ + COi(nq)

r pounds can react with water. forming ions as a product, ..i7. 2 W (aq) + Sol~· (aq)-+ H10(f) + S01(aq) and thus can act as electrolytes.

r s. N l-Vlaq), so/- (aq); Mn2· caqJ, Cl (aq) 49. Ba2 ... (aq) + SOi-(aq) - BaS03(S)

7. i2" (aq). SO/ (aq): K (aq). PO/"(aq) SJ. F~(SO~h(aq) + Co(NOJ)i(aq)-+ NR

r 9. W(aq). NO, (aq); H 1 (aq), Br (aq) SJ. 2 Tr(aq) + MgC03(S)-+ Mg2 ... (aq) + H20(C) + C02(g)

I I. H1C4H404(nq). 1-rF(aq) SS. 2 H (aq) + Pb(OHHs)- Pbl-(aq) + 2 H20(() r

B. 3 ZnH(aq) + 2 P0 43 (aq) - Zn,(P04h(s) S7. 2 CH 30 H(f) + 3 0 2(g)-. 2 C02<g) + 4 H10Ct)

r IS. 2 Fe(s) + 6 W Caql- 3 1-12(g) + 2 Fe1t(aq) 59. HC1Hs01(s) + 01-naq)-C1Hs0 2-(aq) + H10(C)

17. a2C204(S) + 2 W(aq)-+ H2C20iaq) t 2 Na-(aq) 61. 2 Al(s) + 6 H; (aq)-.2 A IH(aq) + 3 H2(g) r 19. Cu(s) + Li2SO~(aq) -+ N R 63. li""(aq) + HSO, (aq) - H~O(e) + S01Caq)

r 21. Ba(s) + 2 H (aq)- H2(g) 4- Ba h (aq) 65. MgS0 1(aq) + NH.1Br(aq)-+ NR

23. i(s) + CaCl2(aq)- NR 67. Mg(s) + ~ WCaq)- MgH(aq) + H2(g) r 25. C3HB(() + 5 0 2(g)- 3 COJ(g) + 4 H10(l') 69. Ni(OHh(s) + 2 W(aq)- NiH(nq) + 2 H20(e)

r 27. C2HsOH((. l + 3 0 2(&)--+ 2 C02(g) + 3 H20(() 71. F(aq) + W(aq)----. H F(aq)

29. Pb1 (aq) + 2 I (aq )-+ Pbl2(s) 73. Ag(s) + HCl(aq)- NR r 31. KCl03(aq) + Mg(N02h(aq)- NR 75. 2 Li(s) + 2 1-12oce>- 2 Li+(aq) + 2 OH (aq) + H1(g)

r 33. Ag+(aq) + Br- (aq)---+ AgBr(s) 77. 1 Al(s) + 3 Cu2• (aq)-2 AJ.l+(aq) + 3 Cu(s)

3S. Zn2"' (aq )+ SO/ (aq)- ZnS01(s) 80. True: a. b. c. h, i,j. k. n. False: d. e, f, g. I. m. r

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