ZXTape! 0Created with Ramsoft MakeTZXb1 JIILId:n=79 :n,9 ;"STOP THE TAPE!":n:502:15,3;"Press any key to continue":0: L10 ,0;"" V5n=11 20:2:n,0;"":n `1n=020:2:21,n;"":n j;n=2011 -1:2:n,20;"":n t10 ,20;"" 5:1 m=2013 -1  m,0; &n=020:1:" ";:n m 7:0 12 ,0;"" 5n=119:2:12 ,n;"":n (12 ,20;"" x5:1 13 ,0;  5 )"     "  5 3"     "  5 5"       "  5 " "  5 &"   "  5 5"     "  5 7"       "  5 "  "  10 40:7:19,21;"Educational" 20,21;"Software" @A200::502:2,1;"TYPES of REACTION" Jr100d:5,2;" 1983";7,2;"CP Lawrence";8,2;"MA (Cantab.), MA (London)" ^ 200: ):n=07:usr:"f"+n,usr:n 'n=07:usr:"g"+n,usr:n 'n=07:usr:"k"+n,usr:n 'n=07:usr:"h"+n,usr:n 'n=07:usr:"t"+n,usr:n  'n=07:usr:"a"+n,usr:n 'n=07:usr:"b"+n,usr:n  'n=07:usr:"d"+n,usr:n *'n=07:usr:"p"+n,usr:n 4'n=07:usr:"m"+n,usr:n >'n=07:usr:"l"+n,usr:n H'n=07:usr:"c"+n,usr:n R'n=07:usr:"q"+n,usr:n ":n$="TYPES of REACTION":n$ V502:''"Different chemical reactions mayinvolve many different sub-"'"stances." J250:'"But many reactions have general characteristics in common." I200:'"Reactions may therefore be"'"grouped together into types." 502:8100::n$ 502:''"We will look at:" y=4:e$="Combination":8310v :e$="Displacement":8310v :e$="Decomposition":8310v :e$="Double decomposition":8310v 3080 :3100 <502:8100::n$="COMBINATION":502:n$ I502:'"Two or more substances combine to form a new substance.": :200:''"1 burning magnesium ribbon in air" &f150:39',87W:0,9 :491,0:0,-9 :-491,0 0.502:x=80P:y=480:8320 :I502:1:10 ,10 ;" ";9 ,10 ;" " D502:8320 :0 N{502:9 ,13 ;"The magnesium burns";10 ,13 ;"with a brilliant";11 ,13 ;"white flame." X3100d:34",100d:59;,0, be502:1:n=9 5-1:10 ,n;" ";9 ,n;"  ":20:n l 20:9 ,5;" " ve502:39',87W:0,9 :491,0:0,-9 :-480,0 0 \502:13 ,13 ;"A white ash remains";14,13 ;"(magnesium oxide)." 9200:17,4;"2Mg(s) + O(g) 2MgO(s)" ]3080 :150:''"2 heating a mixture of iron"'" filings and powdered sulphur" V250:15,103g:0,-16:579,0:0,16 +502:10 ,2;"" .502:x=40(:y=480:8320 T502:10 ,5;"":502:10 ,4;" " а502:9 ,11 ;"The mixture begins to";10 ,11 ;"glow red; and carries";11 ,11 ;"on glowing after the";12 ,11 ;"heat is removed." )300,:1:8320 :0 502:10 ,3;" ":502:10 ,2;" ":502:10 ,2;" " [100d:10 ,2;"":502:10 ,2;" " j502:14,0;"When the reaction has stopped, anew substance is left (iron (II)sulphide)." 6250:18,5;"Fe(s) + S(s) FeS(s)" "502:3340 :3360 38100::502:n$="DISPLACEMENT":n$ z502:'"One element or group of elementstakes the place of another ele- ment or group of elements in a compound.": :300,:'"1 zinc and dilute hydrochloric acid" *]100d:22,79O:0,-535:19,0,2:0,535 4/502:23,480:17,0 >502:10 ,9 ;"Drop a few pieces of";11 ,9 ;"granulated zinc into a";12 ,9 ;"test tube containing";13 ,9 ;"dilute hydrochloric";14,9 ;"acid." H250:1:18,3;"":10 :18,4;"":0:10 :17,3;"":10 :16,3;"" R]502:16,9 ;"The liquid will immed-";17,9 ;"iately effervesce." \100d:19,9 ;"Put your thumb over the";20,9 ;"end of the test tube";21,9 ;"for a few seconds.":150:3430f :3440p fa557,96`:-40(,-4,.1}L:8,-12 ,/2:32 ,0: p1502:8100:w$="10091122":8200 z10 ,9 ;"Remove your thumb, and";11 ,9 ;"at the same time put a";12 ,9 ;"lighted splint near the";13 ,9 ;"mouth of the test tube." )300,:1:3430f :0 {502:557,87W:-23,0:2;0,8,-1.2:2;0,-8,-1.2 K20:10 ,3;"**";11 ,3;"** " N.02{# =,1:.02{# =,2:.02{# =,10 :.02{# =,36$ 910 :10 ,3;" ";11 ,3;" " {502:15,9 ;"The gas in the tube";16,9 ;"will ignite with a";17,9 ;"squeaky pop." 5200:19,9 ;"The gas is hydrogen." 1502:8100:w$="10020929":8200 M11 ,0;"Zinc is above hydrogen in the electrochemical series." >200:''"It therefore displaces hydrogen from an acid." K200:''" Zn(s) + 2HCl(aq)";21,12 ;" ZnCl(aq) + H(g)" p502:8100:w$="11000530":8200 :w$="19000231":6:1:8200 :7:0 502:10 ,0;"In other words, zinc will dis- place hydrogen from a solution of hydrogen ions. The ionic"'"equation therefore reads:" G300,:'" Zn(s) + 2H(aq)";17,12 ;" Zn(aq) + H(g)" 502:3340 >200:'"2 chlorine and potassium bromide solution" $100d:23,87W:0,-480:33!,0:0,480:502:24,72H:31,0 .x502:8,90Z:24,0:0,-40(:8,94^:28,0:0,-44, 8502:10 ,9 ;"Bubble chlorine (from a";11 ,9 ;"chlorine generator)";12 ,9 ;"through a solution of";13 ,9 ;"potassium bromide." Bl250:15,9 ;"This must be done in a ";16,9 ;"fume cupboard. " LC100d:14,5;"":20:13 ,6;"" VF502:n=13 16:n,3;1;" ":n `;502:18,0;"The liquid turns red-brown." jE100d:'"A red bubble may separate at thebottom of the liquid." t)150:16,3;" " ~L502:8100:w$="10090622":8200 :w$="18000331":8200 11 ,9 ;"Chlorine is a more";12 ,9 ;"reactive halogen than";13 ,9 ;"bromine, and will dis-";14,9 ;"place bromine from a";15,9 ;"solution of bromide";16,9 ;"ions." \300,:19,1;"2KBr(aq) + Cl(g)";21,12 ;" 2KCl(aq) + Br(aq)" p502:8100:w$="11090521":8200 :w$="19000231":6:1:8200 :0:7 \502:10 ,9 ;"Expressed as an ionic";11 ,9 ;"equation, this is:" ]150:13 ,10 ;"2Br(aq) + Cl(g)";15,12 ;" 2Cl(aq) + Br(aq)" >502:8100::n$="DECOMPOSITION":502:n$ f502:'"A compound splits into simpler substances - very often purely as a result of heating." >300,:'"A second substance is not"'"normally required." qf=0:100d:''"Examples of decomposition"'"include the various methods of making copper (II) oxide." 250:'"These are used in the experimentwhich illustrates the law of"'"constant composition.":g$="water vapour":c$="copper (II) hydroxide":3820:3930Z 502:8100::n$ ]502:'"Different copper (II) compounds are each heated to constant massin a crucible." V200:31,103g:0,-16:25,0:0,16  T502:16,40(:8,46.:39',0:8,-46. .502:0,39':87W,0 +502:10 ,4;" " X502:513,91[:32 ,0:10 ,11 ;5;1;c$ #f=18330 (.502:x=40(:y=480:8320 25100d:10 ,4;1;"" <]502:45-,108l:40(,0:8,11 ;g$:f=18340 F'502:10 ,4;" " PY502:w$="10110020":8200 :502:10 ,11 ;"copper (II) oxide": Z<502:19,2;"Cu(OH)(s) CuO(s) + HO(g)" n=c$="copper (II) carbonate":g$="carbon dioxide":3820 x:502:19,3;"CuCO(s) CuO(s) + CO(g)" Bf=1:c$="copper (II) nitrate":g$="and oxygen":3820 \502:19,2;"2Cu(NO)(s)";21,5;" 2CuO(s) + 4NO(g) + O(g)" 502:8100 :n$:502:''"In the experiment to demonstratethe law of constant composition the three samples of copper (II)oxide are each reduced to"'"metallic copper." E300,:'"This is done by heating them in a stream of hydrogen." >150:'"The experiment is described in alater program." E502:8100::502:n$="DOUBLE DECOMPOSITION":n$ f502:'"Two compounds are ""decomposed"" and form two new compounds by anexchange of radicals:" 1250:7,7;"AB + CD AD + CB" l100d:10 ,2;"Why ""decomposed""?":100d:'"This will be explained later on." A200:w$="10020016":8200 :w$="12000031":8200 L502:10 ,0;"In a common type of double de- composition," 150:7,7;1;"   ";13 ,3;"AB + CD : both will be";14,13 ;"soluble in water" _200:7,7;1;" ";13 ,3;1;" ":502 7,17;1;"   ";16,3;"AD + CB : one will be soluble";17,13 ;"and the other";18,13 ;"insoluble" "r200:7,17;1;" ";16,3;1;" ":502:8100::n$ ,^502:'"Double decomposition is there- fore a convenient way to make aninsoluble salt." 6(300,:'"eg copper (II) carbonate" @(100d:'"Mix dilute solutions of:" JU100d:71G,67C:0,-36$:41),0:0,36$ TT502:71G,71G:-64@,0:0,17:64@,0 ^I502:10 ,16;"copper (II)";11 ,16;"nitrate" h502:12 ,1;" ":502:w$="12010007":8200 :w$="17090004":5:8200 :w$="16090004":8200 r\7:502:13 ,21;"+":502:15,16;"sodium carbonate" |502:12 ,1;" ":502:w$="12010007":8200 :w$="17090004":1:5:8200 :w$="16090004":8200 Zw$="15090004":1:5:8200 :w$="14090004":8200 :0:7 m72H,64@:39',0:100d:n=1417:n,9 ;1;"":n d502:w$="14090104":8200 :w$="16090104":1:5:8200 :7:0 9502:19,0;"A blue precipitate forms." *100d:'"What is a precipitate?" 502:8100::n$ c502:''"A precipitate is an insoluble solid which forms when solutionsreact together." (250:''" What insoluble solid?" )100d:'"copper (II) carbonate" A100d:''" What has happened?":502:8100::n$ v502:'"The solutions of copper (II)"'"nitrate and sodium carbonate canbe regarded as being completely ionised:" A300,:'"Cu(NO)";7,26;"NaCO" 502:132,119w:0,-47/:502:9 ,11 ;"NO";11 ,5;"NO Cu":502:9 ,18;"Na";11 ,18;"CO Na" &100d:w$="07160500":8200 502:13 ,0;"Immediately they are mixed to- gether, the liquid will contain free copper (II), nitrate,"'"sodium and carbonate ions." r300,:'"Different combinations of these ions will collide with each"'"other, millions of times a"'"second." &L502:8100:w$="02000331":8200 :w$="13000831":8200 02,0;"If a collision causes the ions to combine to form an insoluble compound, this compound will"'"separate out as a precipitate." :300,:13 ,0;"Copper (II) nitrate and sodium carbonate are obviously soluble,since they were the original"'"solutions. Sodium nitrate"'"(NaNO) is also soluble." D`350^:'"Copper (II) carbonate (CuCO) however is insoluble, and forms the precipitate." N200:w$="11110010":1:5:1:8200 :502:0:0:7:11 ,11 ;" CuCO " X502:8100::n$ b:502:'"The overall reaction can be"'"expressed as:" lU100d:'" NaCO(aq) + Cu(NO)(aq)";7,8;" 2NaNO(aq) + CuCO(s)" vh300,:'"But the original compounds were in ionised form. A more accurateionic equation would be:" 250:13 ,4;"2Na(aq)";15,2;"+ 2NO(aq)";17,2;"+ Cu(aq)";19,2;"+ CO(aq)" -200:16,15;"":502 `13 ,20;"2Na(aq)";15,18;"+ 2NO(aq)";17,18;"+ CuCO(s)" 1502:8100:w$="02000931":8200 b2,0;"Neither the sodium ions nor the nitrate ions took any part in the reaction." a200:'"Such ions are called spectator ions, and can be excluded from the equation." T200:w$="13020226":8200 :17,2;" ";17,18;" " /16,15;" ";18,15;"" ڥ502:10 ,0;"This is why ""decomposed"" was in quotation marks. The copper (II)nitrate and sodium carbonate"'"were already decomposed into"'"ions." 300,:'"No further decomposition took place, only an ionic association(another name for this kind of reaction): "''" Cu(aq) + CO(aq) CuCO(s)" 100d:8100 b7:7::502:3,0;"Press:";5,6;"1 to repeat this program";7,6;"2 to load the next program";9 ,6;"3 to stop" l5502:n=10 :17,3;"think" v.n:t$="tank":18,3;5;t$ Mn:23,44,:0,-21:41),0:0,21 (n:23,40(:41),0 fm=63-1:n/502,24+2*m:5;18,m;"";t$(m-2):m '2*n:18,3;"t" ]m=36:n/502,21+3*m:5;18,m;t$(m-2);"":m '2*n:18,6;"k" ="1"1000  ="3" (B="2":502:8,8;"START THE TAPE":"" 2 7060 @ ""press ENTER to continue ";w$: vi=w$(2):j=w$(34):k=w$(56):l=w$(7):z=ii+k:m=jj+l:z,m;" ":m:z: v.100d:y=y+2:y,4;"* ";e$: x,y:0,15:1,0:5:3,14,-1.2:2,-14,-1.2:0:1,0:0,-15: 502:13 ,12 ;"This must be done ";14,12 ;"in a fume cupboard":502:11 ,40(:0,84T:65A,0:0,-84T: (7,11 ;"nitrogen dioxide": #2K0,480,122z,188,252,122z,480,0 #'n=07:usr:"l"+n,usr:n \'n=07:usr:"m"+n,usr:n f'n=07:usr:"h"+n,usr:n p'n=07:usr:"b"+n,usr:n z'n=07:usr:"d"+n,usr:n 'n=07:usr:"o"+n,usr:n 'n=07:usr:"q"+n,usr:n .n$="CHEMICAL COMBINATION & the MOLE":n$ A502:''"An earlier program referred to an important law:" 8200:'"The Law of Constant Composition." %200:''"It is also known as:" 8150:'"The Law of Definite Proportions." R200:''"It states:":502:w$="16000331":6:1:8200 502:16,0;"All pure samples of the same"'"chemical compound contain the same elements combined together in the same proportions by mass." (7:0:502:8100 ::n$="The LAW of CONSTANT COMPOSITION":502:n$ 502:'"The law can be illustrated by anexperiment in which three"'"different samples of copper (II)oxide are reduced to metallic copper." &n350^:''"Copper (II) oxide can be made bythe decomposition of three"'"different copper (II) compounds:" 0300,:'" copper (II) hydroxide":100d:'" copper (II) carbonate":100d:'" copper (II) nitrate" :J150:''"Each compound is heated to"'"constant mass in a crucible." D502:8100::n$ N.502:''"copper (II) hydroxide:" X.100d:'" Cu(OH)(s) CuO(s) + HO(g)" b/300,:''"copper (II) carbonate:" l.100d:'" CuCO(s) CuO(s) + CO(g)" v-300,:''"copper (II) nitrate:" M100d:'"2Cu(NO)(s) 2CuO(s) + 4NO(g)";17,17;"+ O(g)" X300,:'"The last experiment must be donein a fume cupboard. " 502:8100::n$ O502:'"Each sample is then reduced by heating in a stream of hydrogen:" 200:15,1;"1 Put a small portion of copper";16,3;"(II) oxide in a previously";17,3;"weighed porcelain boat." *250:10 ,15;"" _502:19,1;"2 Reweigh the boat + copper";20,3;"(II) oxide." L502:8100:w$="02000131":8200 :w$="15010530":8200 \502:13 ,1;"3 Put the boat in a combustion";14,3;"tube." ڲ150:70F,112p:131,0:70F,87W:131,0:502:8,9 ;" ";9 ,9 ;"";10 ,9 ;" " ]502:8,23;" ";9 ,23;"";10 ,23;" " 502:64@,103g:32 ,0:64@,100d:32 ,0:502:176,103g:480,0:0,16:176,100d:513,0:0,19 502:w$="16000531":6:8200 :7:502:16,0;"In the reaction, water vapour isproduced which could condense at*. This end of the tube should be lower than the other to pre- vent water running back onto thehot glass." o502:10 ,21;"*":502:8100:10 ,21;" ":w$="13000831":8200 m502:17,1;"4 Heat the copper (II) oxide in";18,3;"a stream of hydrogen." =250:8,0;"hydrogen";9 ,5;"" /502:x=120x:y=480:8320 502:2,0;"When the hydrogen has been pass-ing long enough to expel all theair from the tube, the"'"excess can be burnt." m300,:5:224,120x:2,14,-1.2:1,-14,-1.2:0 *1502:8100:w$="17010430":8200 4U17,0;"The copper (II) oxide will glow and leave reddish brown copper." >n200:10 ,15;"":502:w$="02000131":8200 :w$="04000121":8200 Hw502:2,0;"Remove the heat, but leave the hydrogen passing through the"'"tube until it cools down." RA300,:w$="12150303":8200 :w$="17000131":8200 \X502:15,0;"This prevents air getting in andre-oxidising the copper." fa250:''" 5 When it has cooled down, re-";20,3;"weigh the boat + copper." p502:8100::n$ z[502:''"Repeat the experiment with each of the other samples of copper (II) oxide." <300,:''"Present your results in the formof a table." &300,:w$="03000631":8200 -w$="02151716":1:8200 :0 502:2,21;"SAMPLE":502:3,18;"1 2 3":502:4,16;"(gm) (gm) (gm)" l100d:6,0;"Mass of boat"'"+ copper":100d:7,16;"9.75 10.36 10.05" j100d:9 ,0;"Mass of empty"'"boat":100d:10 ,16;"8.32 8.25 7.78" 200:120x,60<:135,0:502:15,0;"Mass of copper":100d:15,16;"1.43 2.11 2.27" ^502:8100:w$="06000111":8200 :w$="07160115":1:8200 :0 y502:5,0;"Mass of boat"'"+ copper (II)"'"oxide":150:7,15;"10.10 10.89 10.61" ޣ150:120x,84T:135,0:502:12 ,0;"Mass of copper"'"(II) oxide":100d:13 ,16;"1.78 2.64 2.83" D150:1:120x,60<:135,0:0 a100d:120x,44,:135,0:100d:17,0;"Mass of oxygen" 6150:17,16;"0.35 0.53 0.56" 502:8100:w$="05000512":8200 :w$="07150416":1:8200 :w$="16150016":8200 :w$="04160015":8200 :0 `502:6,0;"% of copper":100d:6,15;"80.33 79.92 80.21" a200:8,0;"% of oxygen":100d:8,15;"19.67 20.08 19.79" $502:8100::n$ .p502:''"Within the limits of experimen- tal error these results confirm the Law of Constant Composition." 8x300,:'"In all three samples of copper (II) oxide the proportions of copper and oxygen are 80% : 20% by mass." BR300,:''"We know that the chemical form- ula of copper (II) oxide is CuO." LS250:'"But if we did not know it, we could use our results to find it." VB502:8100::502:n$="EMPIRICAL FORMULA":n$ `8502:'"The ratio of"'"copper to oxygen = 80 : 20" js200:'"But the ratio of atoms is not 80: 20 because copper atoms are much heavier than oxygen atoms." t300,:''"Relative atomic masses:":100d:12 ,10 ;"copper = 64":100d:13 ,10 ;"oxygen = 16" ~m200:'"Ratio of atoms = 80 : 20";15,19;1;"__ __";16,19;"64 16" X200:18,17;"= 1.25 : 1.25":200:20,17;"= 1 : 1" 502:8100::n$ T502:''"The empirical formula of copper (II) oxide is therefore CuO." v250:''"An empirical formula is the onlykind of formula an ionic com- pound like copper (II) oxide canhave." 502:8100::n$:502:'"In the formation of copper (II) oxide, copper atoms react with oxygen atoms in the ratio 1:1." ?300,:3,14;"atoms";4,7;"atoms" 100d:'"Since their relative atomic masses are 64 and 16 respective-ly, copper and oxygen combine inthe ratio 64:16 by mass." %300,:9 ,19;"mass" E100d:'"So 64 gm of copper will combine with 16 gm of oxygen." x250:'"So the atomic mass in grams of copper combines with the atomic mass in grams of oxygen. " n300,:'"So one mole of copper atoms com-bines with one mole of oxygen atoms." 9502:8100::502:n$="The MOLE":n$ b502:''"It is difficult to overestimate the importance of the mole in chemistry." D300,:7,16;"";8,15;"****" F502:3:122z,112p:27,0,-:0  r502:10 ,0;"According to the kinetic theory chemical reactions take place between particles." 502:8100::n$ s502:'"If two molecules of hydrogen"'"combine with one molecule of"'"oxygen to form two molecules of water:" (Q300,:7,11 ;" ":502:9 ,13 ;"" 2W100d:7,11 ;" ";7,16;" ";8,11 ;" " <@100d:9 ,13 ;" ";8,12 ;" " F100d:11 ,0;"then eight molecules of hydrogenwill combine with four moleculesof oxygen to form eight mole- cules of water:" PC300,:17,1;" " Z>502:19,3;" " d;100d:n=1258:17,n;" ":n n0n=6308:17,n;" ":n x818,1;" " ;100d:19,3;" " 4n=2268:18,n;"":n 4n=5298:18,n;"":n +100d:21,0;"and so on." 502:8100::n$ [502:''"For convenience, chemists use a standard number of particles as their unit." (300,:''"The particles could be:" X150:'" * atoms;":502:'" * molecules;":502:'" * ions." W100d:''"The standard unit is the mole.":100d:19,26;"" 3502:19,0;"How much is a mole?" 502:8100::n$ ;''"Let A = the number of atoms in 1gram of hydrogen." H200:''"How many oxygen atoms will therebe in 1 gram of oxygen?" f250:''"Relative atomic masses:":100d:'" hydrogen = 1":100d:'" oxygen = 16" 502:8100::n$ 502:'"An oxygen atom is 16 times heav-ier than a hydrogen atom.":250:'"If the number of hydrogen atoms in 1 gm of hydrogen" "(250:8,10 ;"= A" ,100d:'"then the number of oxygen atoms in 1 gm of oxygen":250:13 ,10 ;"= A";13 ,12 ;1;"__";14,12 ;"16" 6150:'"The mass of A atoms of oxygen":150:18,10 ;"= 16 gm":100d:20,10 ;"= the relative atomic";21,12 ;"mass in grams. " @502:8100::n$:502:'"Since the relative atomic mass of hydrogen = 1, then 1 gram of hydrogen is also its relative atomic mass in grams." J8350^:w$="04000131":1:8200 :0 TI''"How many hydrogen molecules willthere be in 1 gram of hydrogen?" ^c200:n=12 202:m=6243:n,m;"":10 :m:n h502:8100::n$ rG502:'"There are 2 hydrogen atoms in each hydrogen molecule." |k200:'"So if there are A hydrogen atomsin a gram, there will be A/2"'"molecules in a gram." F300,:''"Therefore the mass of A mole- cules of hydrogen" 200:13 ,10 ;"= 2 gm":100d:15,10 ;"= relative molecular";16,12 ;"mass in grams. " 502:8100::n$ +502:'"What is a mole? ()" 100d:''"1 mole of atoms = the relative ";6,18;"atomic mass in";7,18;"grams. " 300,:''"1 mole of molecules";12 ,16;"= the relative ";13 ,18;"molecular mass";14,18;"in grams. " …300,:''"1 mole of ions = the relative ";18,18;"ionic mass ";19,18;"in grams. " w502:8100::n$:502:w$="02001920":6:1:8200 :w$="02211910":7:8200 ֑502:6:2,0;"1 mole of:":100d:''" hydrogen atoms":502:'" hydrogen molecules":502:'" hydrogen ions" 502:'" sodium atoms":502:'" sodium ions":502:'" chlorine atoms":502:'" chlorine molecules":502:'" chloride ions":502:'" sodium chloride" 100d:7:2,24;"grams":100d:5,26;1:502:7,26;2:502:9 ,26;1:502:11 ,25;23 502:13 ,25;23:502:15,25;35.5:502:17,25;71G:502:19,25;35.5:502:21,25;58.5j %0:502:8100::n$ }502:''"All of these moles (with the"'"exception of sodium chloride) contain the same number of"'"particles: A." O300,:''"Ionic compounds like sodium"'"chloride are a special case." 9250:'"There are no molecules of sodiumchloride." &y250:''"What we can say is that 1 mole (58.5 grams) of sodium chloride contains A formula units (NaCl)." 0502:8100::n$ :v502:''"1 mole of sodium chloride con- tains 1 mole of sodium ions and 1 mole of chloride ions." D300,:''"1 mole of magnesium chloride (MgCl) contains 1 mole of magnesium ions and 2 moles of chloride ions." Ne502:8100::n$:502:'"1 mole of hydrogen atoms":100d:2,27;"" XU100d:'"and 1 mole of hydrogen"'"molecules":150:5,26;"" b:100d:'"and 1 mole of sodium"'"chloride":150 l#9 ,20;" " v&10 ,19;" " (11 ,18;" " )12 ,17;" " 313 ,15;"  " 314,15;"  " 115,19;"   " 116,19;"   " Q100d:'"all have the same number (A) of particles (or formula units)." >502:8100::n$:502:''"How many is A?" <100d:6,8;"A = 6.02 x 10 (approx.)" :100d:8,3;"(602000000000000000000000)" v100d:''"A is called the Avogadro number.It is named after an Italian scientist, Amadeo Avogadro." 502:8100 b7:7::502:3,0;"Press:";5,6;"1 to repeat this program";7,6;"2 to load the next program";9 ,6;"3 to stop" l5502:n=10 :17,3;"think" v.n:t$="tank":18,3;5;t$ Mn:23,44,:0,-21:41),0:0,21 (n:23,40(:41),0 fm=63-1:n/502,24+2*m:5;18,m;"";t$(m-2):m '2*n:18,3;"t" ]m=36:n/502,21+3*m:5;18,m;t$(m-2);"":m '2*n:18,6;"k" ="1"1000  ="3" (B="2":502:8,8;"START THE TAPE":"" 2 7060 ""press ENTER to continue ";w$: vi=w$(2):j=w$(34):k=w$(56):l=w$(7):z=ii+k:m=jj+l:z,m;" ":m:z: vx,y:0,15:1,0:5:3,14,-1.2:2,-14,-1.2:0:1,0:0,-15: _x,y:0,15:3,0:n=13:8330 :n:0,-15: `5:3,14,-1.2:2,-14,-1.2:0:3,0: #2K0,480,122z,188,252,122z,480,0 #,127,255,34" #J7,15,31,63?,255,255,12 ,12 #O252,254,255,255,255,255,12 ,12 #N60<,90Z,219,195,219,219,126~,60< #O60<,102f,219,219,219,231,126~,60< #I204,34",68D,130,236,0,0,0 b3 P88wR8d:n=79 :n,9 ;"STOP THE TAPE!":n:502:15,3;"Press any key to continue":0: L10 ,0;"" V5n=11 20:2:n,0;"":n `1n=020:2:21,n;"":n j;n=2011 -1:2:n,20;"":n t10 ,20;"" 5:1 m=2013 -1  m,0; &n=020:1:" ";:n m 7:0 12 ,0;"" 5n=119:2:12 ,n;"":n (12 ,20;"" x5:1 13 ,0;  5 )"     "  5 3"     "  5 5"       "  5 " "  5 &"   "  5 5"     "  5 7"       "  5 "  "  10 40:7:19,21;"Educational" 20,21;"Software" @D200::502:2,1;"CHEMICAL EQUILIBRIUM" Jr100d:5,2;" 1983";7,2;"CP Lawrence";8,2;"MA (Cantab.), MA (London)" ^ 200: ):n=07:usr:"f"+n,usr:n 'n=07:usr:"g"+n,usr:n 'n=07:usr:"h"+n,usr:n 'n=07:usr:"q"+n,usr:n 'n=07:usr:"t"+n,usr:n  'n=07:usr:"a"+n,usr:n 'n=07:usr:"d"+n,usr:n  'n=07:usr:"l"+n,usr:n *'n=07:usr:"r"+n,usr:n 4'n=07:usr:"c"+n,usr:n >'n=07:usr:"p"+n,usr:n H'n=07:usr:"m"+n,usr:n R'n=07:usr:"i"+n,usr:n \'n=07:usr:"j"+n,usr:n f'n=07:usr:"k"+n,usr:n #n$="REVERSIBLE REACTIONS":n$ m502:'"If hydrated copper (II) sulphateis heated gently, the blue crys-tals turn into a white powder." %300,:w$=" ":8330 .502:x=40(:y=568:8320 +100d:9 ,4;"" '100d:9 ,4;" " &100d:w$="11050300":8200 502:7,11 ;"The hydrated salt";8,11 ;"loses its water of";9 ,11 ;"crystallization and";10 ,11 ;"becomes anhydrous";11 ,11 ;"copper (II) sulphate." I300,:''" CuSO.5HO(s)";16,11 ;" CuSO(s) + 5HO(g)" D300,:'"This reaction is endothermic"'"(H is positive)." &502:8100::n$ 0$502:w$=" ":8330 :R502:2,0;"Let the powder cool, and add a few drops of water." D250:8340 X}502:5,11 ;"The dish will grow";6,11 ;"hot and the powder";7,11 ;"will turn blue." bR300,:9 ,4;"":100d:9 ,4;" " l502:9 ,11 ;"The anhydrous salt";10 ,11 ;"has regained its";11 ,11 ;"water of crystalliz-";12 ,11 ;"ation." vH300,:'" 5HO(l) + CuSO(s)";16,16;" CuSO.5HO(s)" C300,:'"This reaction is exothermic"'"(H is negative)." 502:8100::n$ d502:''"The water of crystallization is lost as steam (g), but regained by adding water (l)." 0300,:''"After allowing for latent heat:" t200:'" (5HO (l) 5HO(g); H +ve)":250:'"the H values of the forward andreverse reactions are" S250:'" * equal in value":100d:'"but * opposite in sign." 502:8100::n$ Y502:''"A reaction which goes both ways like this is called a reversiblereaction." A300,:''"It is usually written with a rather than a ." I250:''" CuSO.5HO(s)";14,11 ;" CuSO(s) + 5HO(g)" 502:8100::n$ J502:'"Some reversible reactions can goboth ways at the same time." 250:5,9 ;"Add 2M hydrochloric";6,9 ;"acid drop by drop to 10";7,9 ;"cm of 0.2M lead (II)";8,9 ;"nitrate solution until";9 ,9 ;"no more precipitation";10 ,9 ;"occurs." 350^:8400 502:8340 I502:w$="09040302":1:1:8200 :0:0 M502:8340 :502:w$="09040102":1:8200 :0 *502:12 ,9 ;"Filter off the solid";13 ,9 ;"lead (II) chloride, and";14,9 ;"keep the filtrate." 4P300,:''"This will be a saturated solu- tion of lead (II) chloride." >2502:8100::n$:502:8360 H502:3,18;"Transfer the";4,18;"filtrate to a";5,18;"Geiger-Muller";6,18;"tube, and take";7,18;"a reading on";8,18;"the Scaler." R300,:5,7;"tube":502:7,10 ;"Scaler":502:c=4:p=100d:8380 :8390 \10 ,18;"Find the num-";11 ,18;"ber of counts";12 ,18;"per minute for";13 ,18;"a 5 minute";14,18;"period." fV8390 :'"This will give you the 'back- ground' count.":c=2:8390 pN'"Put the solution back into a"'"beaker.":c=2:8390 :8100 zQ:n$:502:'"Next make a radioactive sample of solid lead (II) chloride." 250:5,9 ;"Add 10 cm of 0.1M";6,9 ;"thorium nitrate solu-";7,9 ;"tion to 5 cm of 0.2M";8,9 ;"lead (II) nitrate";9 ,9 ;"solution." 300,:8400 502:11 ,9 ;"Add 2M hydrochloric";12 ,9 ;"acid drop by drop until";13 ,9 ;"no more precipitation";14,9 ;"occurs." 300,:8340 I502:w$="09040302":1:1:8200 :0:0 M502:8340 :502:w$="09040102":1:8200 :0 d502:16,0;"Filter and wash the solid, whichwill contain radioactive Pb"'"ions." 502:8100::n$ Ԁ502:''"Add the radioactive solid lead (II) chloride to the saturated solution of lead (II) chloride made previously." +300,:''"Stir for about 12 minutes." }150:''"Filter off the solid, and"'"transfer the (perfectly clear) filtrate to the Geiger-Muller tube once again." 502:8100::n$ ,502:8360 :502:8380 502:3,18;"Take another";4,18;"reading on the";5,18;"Scaler, and";6,18;"find the count";7,18;"per minute for";8,18;"5 minutes." /200:p=20:c=20:8390 502:10 ,18;"The count rate";11 ,18;"will be much";12 ,18;"higher than";13 ,18;"before." $c=25:8390 .502:15,0;"The solution now contains radio-active Pb ions, which must havecome from the radioactive lead (II) chloride solid." 8K8390 :'"But how could a saturated solu- tion absorb more Pb ions?" Bx200:w$="15000631":1:1:6:8200 :0:7:0:502:8100::n$ L;502:''"A dynamic equilibrium has been set up:" V0150:''" PbCl(s) Pb(aq) + 2Cl(aq)" `w250:''"The saturated solution cannot take any more Pb ions, but it can exchange Pb ions with the solid." jJ300,:''"Pb ions enter and leave the"'"solution at the same rate." tE502:8100::n$="CHEMICAL EQUILIBRIUM":502:n$ ~V502:14,0;"Chemical equilibrium can be"'"represented graphically." ;250:h=100d:p=2:eq=2:85004! _17,0;" and  particles combine to"'"form  particles.":8535W! {20,0;"At the same time  particles split up into  and  particles.":h=200:8535W! w$="14000731":8200 502:14,0;"The proportions of ,  and  which will be present when the equilibrium point is reached"'"will vary from one reaction to another." Jh=100d:8535W!:20,10 ;"REACTION 1":8535W! Ā:502:20,10 ;" ":502:20,10 ;"REACTION 2":eq=4:h=800 :8535W! i20,10 ;" ":502:20,10 ;"REACTION 3":eq=8:8535W! ةw$="14000631":8200 :14,0;"Do not assume that equilibrium occurs when the concentration of""products"" equals the concentra-tion of ""reactants""." %eq=4:h=400:8535W! n19,0;"Equilibrium is reached when the reaction is going at the same rate in both directions." 502:8100::n$ 502:h=100d:85004!:14,0;"The rate of the forward reactionvaries with the concentration of and ."  i8535W!:18,0;"The rate of the reverse reactionvaries with the concentration of."  h=300,:8535W!:w$="14000631":8200 :14,0;"As  and  get used up, the rateat which they combine gets slow-er and slower until it is equal to the rate at which  splits up (which depends on the concen-tration of )." h=800 :8535W! (502:8100::n$ 2\502:14,0;"A change in temperature can"'"affect a reaction in two ways." <250:'"1 An increase in temperature"'"will speed up both the forward reaction and the reverse reac- tion, and therefore the rate at which equilibrium is reached." F0300,:p=.5:h=200:85004! P1502:8100:w$="17000431":8200 Z502:17,0;"2 An increase in temperature"'"will move the equilibrium in"'"favour of the endothermic reac- tion. A drop in temperature willfavour the exothermic reaction." d#300,:eq=2:8535W! n 8100 b7:7::502:3,0;"Press:";5,6;"1 to repeat this program";7,6;"2 to stop" l5502:n=10 :17,3;"think" v.n:t$="tank":18,3;5;t$ Mn:23,44,:0,-21:41),0:0,21 (n:23,40(:41),0 fm=63-1:n/502,24+2*m:5;18,m;"";t$(m-2):m '2*n:18,3;"t" ]m=36:n/502,21+3*m:5;18,m;t$(m-2);"":m '2*n:18,6;"k" ="1"1000  ="2" 2 7060 @ ""press ENTER to continue ";w$: vi=w$(2):j=w$(34):k=w$(56):l=w$(7):z=ii+k:m=jj+l:z,m;" ":m:z: x,y:0,15:1,0:5:3,14,-1.2:2,-14,-1.2:0:1,0:0,-15::burner u24,103g:7,-8:25,0:7,8:502:9 ,4;w$::CuSO Y46.,120x:16,16:42*,124|:16,16:drops 502:n=13:20:7,5;"":20:7,5;" ";8,5;"":20:8,5;" ":n: 31,143:0,-568:17,0:0,568:502:11 ,3;" ";12 ,3;" ":502:568,74J:22,0:Geiger-Muller tube 502:w$="09100305":0:8200 :7:502:10 ,11 ;" ":502:7:95_,79O,4:112p,79O,4:0: {32 ,120x:15,0:502:29,140:0,8:21,0:0,-8: 4502:n=1c:.01z# =,-12 :p:n: }31,119w:0,-480:25,0:0,480:502:32 ,103g:23,0: !>a(10 ,15) !H(l=110 :c=115 !R/l+2,c*2-1;"":c:l !W t=0 !\2l=(*10 )+1:c=(*15)+1 !fa(l,c)=a(l,c)+1 !pa(l,c)=eqa(l,c)=0 !zp:t=t+1:t*ph !Ea(l,c)=0l+2,c*2-1;"":8540\! !3l+2,c*2-1;"":8540\! #2K0,480,122z,188,252,122z,480,0 #