THE COPPER CY CYCLE LAB Matter & Chemical Bonding
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I) Introduction 1) Purpose The !ur!o"e o# the co!!er$to$co!!er la% a" to gain e'!erience ith identi#(ing dierent t(!e" o# chemical reaction"* more "!eci+call( tho"e in,ol,ing co!!er* through hich e learned the e""ential" o# the la o# con,er"ion o# ma"" theor(- A "!eci+c .uantit( o# co!!er ill %e tran"#ormed through a "erie" o# reaction" and then reco,ered a" co!!er- A#ter hich* rele,ant error" ill %e identi+ed and e'!lained/) Hypothesis a) Reaction Reaction A I# co!!er co!!er metal metal i" added to nitric nitric acid* acid* then a "ingle di"!lacement reaction might occur %ecau"e the co!!er the nitric acid ill di"!lace the h(drogen hile creating o'(gen- The %alanced chemical e.uation #or thi" reaction i" Cu0") 2H3O40a.) Cu03O4)/0a.) /3O/0g) /H/O0l)%) Reaction Reaction B I# "odium "odium h(dro'ide h(dro'ide 03aOH) 03aOH) i" added added at room room tem!erature to co!!er0II) nitrate* then a dou%le di"!lacement reaction ill occur* %ecau"e co!!er and "odium ill di"!lace each other to create co!!er0II) h(dro'ide and "odium nitrate The %alanced %alanced chemical chemical e.uation e.uation #or thi" reaction reaction i" Cu03O4)/0a.) /3aOH0a.) CuOH/0") /3a3O40a.)c) Reaction Reaction C I# heat heat a" added to co!!er0II) co!!er0II) h(dro'id h(dro'ide* e* a decom!o"ition reaction ould occur a" the reaction ould decom!o"e to #orm to com!ound"* co!!er 0II) o'ide and ater- The %alanced chemical e.uation #or thi" reaction i" Cu0OH)/0") CuO0") H/O0g)d) Reaction Reaction 5 I# "ul!huric "ul!huric acid a" a" added to the "olution "olution containing co!!er 0II)o'ide* then a dou%le di"!lacement reaction ould occur* %ecau"e the co!!er0II) o'ide ould react ith the "ul!huric acid to !roduce co!!er 0II) "ul!hate and ater* in hich the co!!er and h(drogen ga" ould re!lace each other- The %alanced chemical e.uation #or thi" reaction i" CuO0") H/6O20a.) Cu6O20a.) H/O0l)e) Reaction Reaction E I# 7inc 7inc a" !laced !laced into into the "olution "olution containing containing co!!er0II) "ul!hate* then a "ingle di"!lacement reaction ould occur "ince the 7inc ould #orm a ne com!ound ith the "ul!hate and the co!!er ould remain a" a metal- The %alanced e.uation #or the "ingle di"!lacement reaction i" Cu6O20a.) 8n0a) 8n6O20a.) Cu0")- The 7inc0II) "ul!hate %ra9e" u! into 8n6O20a.) H/6O2 8n6O20a.) H/0g)- Thi" i" %ecau"e* hen "ul!huric acid i" added to remo,e an( unreacted 7inc* 7inc0II) "ul!hate i" !roduced "ince 7inc i" a%o,e h(drogen on the acti,it( "erie"-
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4) Background Information: A chemical reaction i" a !roce"" that lead" to the tran"#ormation o# one "et o# chemical "u%"tance" to another- The "u%"tance 0or "u%"tance") initiall( in,ol,ed in a chemical reaction are called reactant" or reagent"Chemical reaction" are u"uall( characteri7ed %( a chemical change* and the( (ield one or more !roduct"* hich u"uall( ha,e !ro!ertie" dierent #rom the reactant"- Chemical reaction" are de"cri%ed ith chemical e.uation"* hich gra!hicall( !re"ent the "tarting material"* end !roduct"* and "ometime" intermediate !roduct" and reaction condition"- In thi" la% e identi+ed dierent t(!e" o# chemical reaction"* more "!eci+call( tho"e in,ol,ing co!!er* through hich e learned the e""ential" o# the law of conversion of mass theory - Thi" theor( "tate" that #or an( "("tem clo"ed to all tran"#er" o# matter and energ( 0%oth o# hich ha,e ma"")* the ma"" o# the "("tem mu"t remain con"tant o,er time* a" "("tem ma"" cannot change .uantit( i# it i" not added or remo,ed- The la o# con,er"ion o# ma"" a" di"tincti,el( rele,ant to the la% due to the #act that throughout the e'!eriment* e conducted a "erie" o# +,e tran"#er" o# matter and energ( in hich the ma"" o# the "("tem remained theoreticall( con"tant o,er time* although due to "e,eral error" e'!erienced throughout the la%* the ma"" o# the co!!er changed- Throughout thi" la%* e o%"er,ed +,e chemical reaction" in,ol,ing co!!er- The"e ere a redox reaction 0hich include" all chemical reaction" in hich atom" ha,e their o'idation "tate changed) a double displacement reaction 0hich i" a chemical !roce"" in,ol,ing the e'change o# %ond" %eteen to reacting chemical "!ecie"* hich re"ult" in the creation o# !roduct" ith "imilar or identical %onding a:liation")* a decomposition reaction 0the "e!aration o# a chemical com!ound into element" or "im!ler com!ound") and a singledisplacement reaction 0a t(!e o# o'idation$reduction chemical reaction hen an element or ion mo,e" out o# one com!ound and into another)- There are a m(riad o# safety requirements that are !ut in !lace throughout a la%* a" to allo a "tudent to remain "a#e and engaged throughout their e'!eriment- The three main safety risks that one can encounter hile undergoing a la% are a- ;ire there there "hould ne,er ne,er %e o!en o!en
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%- E'!lo"io E'!lo"ion" n" ne,er ne,er heat heat a clo"ed "("tem "("tem or condu conduct ct a reaction in a clo"ed "("tem 0unle"" "!eci+call( directed to !er#orm the latter !roce"" and then onl( ith #re.uent ,enting)- Be#ore "tarting a di"tillation or a chemical reaction* ma9e "ure that the "("tem i" ,ented- The re"ult" o# an e'!lo"ion are <(ing gla"" and "!attered chemical"* u"uall( %oth hot and corro"i,ec- Chemical and Therma Thermall Burn" Burn" man( man( inorgani inorganic c chemical" chemical" "uch a" the mineral acid" and al9ali" are corro"i,e to the "9in and e(e"- Li9ei"e* man( organic chemical"* "uch a" acid halide"* !henol"* and "o #orth are corro"i,e and o#ten to'ic- I# the"e are "!illed on the de"9* in the hood* or on a "hel#* call #or a""i"tance in cleaning them u!-
backg round information used the in#ormation 2) eference to background a%o,e a" !rimaril( "ourced #rom the chemi"tr( te't%oo9 a" ell a" the #olloing e%"ite" a- A%out A%out Educati Education* on* Chemi"t Chemi"tr( r( Home Home Page Page htt!==chemi"tr(-a%out-com= 0acce""ed htt!==chemi"tr(-a%out-com= 0acce""ed Tue"da( 3o,em%er th /> * /?12) %- @i9i!edia* Chemical Reaction* 3o,em%er 1/ th* /?12htt!==en-i9i!edia-org=i9i=Chemicalreaction 0acce""ed Tue"da( Tue"da( 3o,em%er 3o,em%er />th* /?12)
II) Material" !"B#$ % The e.ui!ment u"ed throughout the co!!er$to$ co!!er la% mol=L 3aOH mol=L nitric acid %ea9er tong" 4 mol=L H /6O2 a"h a"h %ott %ottle le 0di" 0di"ti till lled ed)) >?$m >?$mL L %ea9 %ea9er er 7inc 0granular #orm) hot !late "a#et( goggle" co!!er 0!oder #orm) gla"" "tir "tic9 %lue litmu" !a!er red litmu" !a!er glo,e" III) Method 1) Procedure Here i" a detailed "ummar( o# the !rocedure to hich e #olloed in order to com!lete the la%* in "e.uential order and categori7ed %( reactiona) Rea eact ctio ion n A 1Ma"" (o (our em em!t( >? >? mL %ea9er/@itho ithout ut get getti ting ng co!! co!!er er on on the the "ide "ide" " o# (o (our %e %ea9 a9er er** care#ull( !lace o# ?-1? g o# !odered co!!er in (our >? mL %ea9er-
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nde nderr the the teac teache herD rD" " "u! "u!er er,i ,i"i "ion on** add add a!!r a!!ro o'ima 'imate tel( l( / mL o# concentrated H3O 4 0a.) to the %ea9er in the #ume hoodhood- Continu Continue e to add the nitric nitric acid until until no more %ron 3O / ga" i" !roducedAdd / mL mL o# o# di"t di"til ille led d ate aterr to the the %ea %ea9 9er cont contai aini ning ng Cu03O4)/ "olution-
%) Rea eact ctio ion n B >You mu"t mu"t e ear ar glo, glo,e" e" #or #or the the"e "e ne't ne't "te! "te!""- At roo room m tem!erature* hile "tirring ith a gla"" rod* add 1-> mL o# mol=L 3aOH and continue to add the 3aOH a cou!le dro!" at a time until the "olution i" %a"ic to red litmu" litmu" !a!er!a!er- 5o not !ut the red red litmu" !a!er in "olut "olution ion-- 5i! 5i! the gla"" gla"" rod into into the "olutio "olution n and touch it to the litmu" litmu" !a!er!a!er- Be "ure to record record (our (our o%"er,ation"c) Rea eact ctio ion n C @hil @hile e con con"t "tan antl tl( ( "ti "tirrring ring the the "ol "olut utio ion n it ith h a gla" gla"" " rod rod** heat heat the the mi't mi'tur ure e #rom #rom "te! "te! > on a hot hot !lat !late e at medium medium heat until until a %lac9 !reci! !reci!itat itate e i" #ormed#ormed- I# nece""ar(* u"e the a"h %ottle to a"h loo"e an( unreact unreacted ed light$%l light$%lue ue !reci! !reci!itat itate e that i" adherin adhering g to the "ide o# the %ea9er@hen all the light$%l $%lue !reci!itate ha" reacted to #orm the %lac9 !reci!itate* cool the %ea9er in a cool$ ater %ath 0u"e the "in9 ith a cou!le o# centimetre" o# ater) #or "e,eral minute"d) Rea eact ctio ion n 5 F@ea eari ring ng glo glo,e ,e"* "* car care# e#u ull( ll( add add a%o a%out ut mL o# 4 mol= mol=L L "ul!h "ul!hur uric ic acid acid to the the %ea9 %ea9erer- 6tir 6tir it until until all %lac9 %lac9 !reci!itate ha" di""ol,ed- Record (our o%"er,ation"e) Rea eact ctio ion n E GChec Chec9 9 the the aci acidit( it( o# (ou (our "olu "oluttion ion u"in u"ing g %lu %lue litm litmu u" !a!er!a!er- Record Record (our o%"er,ation"o%"er,ation"- In a #ume hood* care#ull( add a%out ?-F g o# 7inc to the "olution o# co!!er0I co!!er0II) I) "ul!hate "ul!hate-- 6tir the "olution "olution until the %lue %lue colour di"a!!ear"- Record (our o%"er,ation"1?1?-
@hen @hen the the rea reacti ction on i" i" com! com!let lete e and and i" i" unde underr the the #ume #ume hood hood** add add > mL o# 4 mol= mol=L L "ul! "ul!hu huri ric c acid acid hil hile e "tirring "tirring or "irlin "irling g the "olution"olution- Thi" Thi" remo,e" remo,e" an( unreacted 7inc %ut doe" not aect the co!!er metalCarre#ul Ca e#ull( l( deca decant nt the the li.u li.uid id into into anot anothe herr %ea9 %ea9er er->
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5i"card the li.uid in the re#u"e container in the #ume hoodAllo the co!!er metal remaining remaining to dr( 0o,ernight)0o,ernight)@hen dr(* ma"" the %ea9er ith co!!erco!!er- Record (our o%"er,ation"-
/) "ssurances of &ata: throughout the la%* m( !artner and I conducted "e,eral mea"urement" #or each indi,idual reaction* u"ing detailed e.ui!ment 0i-e a >? ml %ea9er* #or other in#ormation on the material" u"ed* !lea"e re#er to the Material" "ection o# thi" la%) a" ell a" ent through the !roce"" o# litmu" !a!er te"ting and multi!le trial"* a" to a""ure the outcome o# "u:cient* rele,ant data- ;or in"tance* e re!eated !rocedure / three time"* a" to reduce the !o""i%ilit( o# an incorrect mea"urement* hich could ha,e aected the outcome o# the !roceeding reaction" #or the la%-
IJ) Re"ult" %' (ualitative (ualitative )bservations )bservations !"B#$ * The .ualitati,e o%"er,ation" ta9en throughout throughout the la%eaction " Pre!aring co!!er0II) nitrate Balanced Chemical E.uation Cu0") 2H3O40a.) Cu03O4)/0a.) /3O/0g) /H/O0l) Redo' Reaction Be#ore 5uring A#ter $ Co!!er i" %ron $ Colour and "tate $ The "olutionD" and dr(change o# the colour i" %lue and $ The co!!er i" at co!!er 0#rom a "olid clear* hile al"o non room tem!erature%ron to a green ,i"cou"then %lue li.uid)$ The tem!erature $ Tem!erature decrea"ed to that at change 0it increa"ed hich it a" initiall( throughout the 0room tem!erature reaction)K/1-> C 0?- ;)-
$ Bu%%le" #ormed at $ The ga" cea"ed to the "ur#ace o# the %e !roduced a#ter "olution and a red$ the reaction%ron ga" i" relea"edeaction B: Pre!aring co!!er0II) h(dro'ide Balanced Chemical E.uation Cu03O4)/0a.) /3aOH0a.) Cu0OH)/0") /3a3O40a.) 5ou%le 5i"!lacement Reaction Be#ore 5uring A#ter $ The "olutionD" "olutionD" $ @hen the 3aOH i" $ The !roduct i" a colour i" %lue and added to the co!!er thic9* %lue "olutionclear* hile al"o "olution* it %ecame $ @hen te"ted on %eing non ,i"cou"a dar9er* more litmu" !a!er* it $ The tem!erature "aturated "hade o# %ecame %lue o# the "olution i" %lue0meaning it i" no around room $ The li.uid a" con"idered a %a"ic tem!erature K/1-> clouded and more "olution)C 0?- ;),i"cou" then !rior to $ There i" a "mall $ @hen it a" te"ted the reaction!ortion o# the light on red litmu" !a!er* %lue "olution it remained !in9 adhered to the "ide 0meaning that at o# the %ea9erthi" !oint it i" "till an acid) $ The 3aOH i" a tran"lucent* non$ ,i"cou" li.uideaction +: Pre!aring co!!er0II) o'ide Balanced Chemical E.uation Cu0OH)/0") CuO0") H/O0g) 5ecom!o"ition Reaction Be#ore 5uring A#ter $ The "olution i" $ 5uring the $ A#ter 2? "econd" o# thic9 and %luereaction* %lac9 "!ot" "tirring* the "olution $ @hen te"ted on a!!eared in the turned dar9litmu" !a!er* it li.uid a" it a" $ A#ter "e,eral %ecame %lue heatedminute" 0meaning it i" no $ The colour 0a!!ro'imatel( ) a con"idered a %a"ic changed #rom %lue %lac9 !reci!itate i" "olution)to %ron and #ormed$ There i" a "mall ultimatel( +ni"hed !ortion o# the light in %ecoming %lac9%lue "olution $ @e u"ed a a"h adhered to the "ide %ottle containing
o# the %ea9er-
di"tilled ater to !reci!itate turned C 0?- ;)into clum!"$ The tem!erature o# the ne "olution i" around room tem!erature K/1-> C 0?- ;)-
A#ter $ The "olution i" %lue* clear and non$ ,i"cou"$ It re"em%le" the co!!er0II) nitrate "olution-
eaction $ Regeneration o# the co!!er metal Balanced Chemical E.uation Cu6O20a.) 8n0a) 8n6O20a.) Cu0") 8n6O20a.) H/6O2 8n6O20a.) H/0g) 6ingle 5i"!lacement Reaction Be#ore 5uring A#ter $ @hen the "olution $ @e added ?->g $ A#ter the reaction* i" added to a "tri! o# o# 7inc to the the "olution a" %lue litmu" !a!er* "olution%lue and ,i"cou"and turn" red$ The tem!erature $ @hen the >mL o# o# the "olution 4mol=L "ul!huric increa"edacid i" added the $ The li.uid turned "olution %ecame a into a cloud( gre(* cloud( hite%u%%le" are $ A#ter decanting !roduced and a" a !roce""* a red 7inc re"ult a ga" i" i" le#t at the %ottom relea"edo# the %ea9er The li"t o# .ualitati,e .ualitati,e o%"er,ation" recorded throughout the la%* more "!eci+call( in,ol,ing in,ol,ing the +,e main reaction" that co!!er ent through 0co!!er
F
metal metal ith nitric acid co!!er0II) h(dro'ide h(dro'ide "ul!hate co!!er metal)-
co!!er0II) co!!er0II)
o'ide
co!!er0II)
*' (uantit (uantitative ative )bservatio )bservations: ns: !"B#$ , The .ualitati,e o%"er,ation" ta9en throughout the
la%Ma"" o# em!t( %ea9er* Mi =g 0 ?-???> g) Ma"" o# %ea9er co!!er %e#ore reaction"* Mt =g 0 ?-???> g) Ma"" o# co!!er %e#ore reaction"* M! =g 0 ?-???> g) Ma"" o# %ea9er a#ter reaction" * M# =g =g 0 ?-???> g) Amount o# concentrated H3O40a.) =mL 0 ?-> mL) Amount o# mol=L 3aOH =mL 0 ?-> mL) Amount o# 4 mol=L "ul!huric acid =mL 0 ?-> mL) Amount o# 7inc added to co!!er0II) "ul!hate "olution =g 0 ?-???> g) Molar ma"" o# co!!er* Mc =g=mol Initial Mole" o# Co!!er* 3i =mol Cu ;inal Mole" o# Co!!er* 3# =mol Cu
4>-> g 4>-F>? g
?-?G4 g
3A 0e did not get the chance to calculate the +nal ma"" at the end o# cla"") / mL
1-> mL mL ?-F g
4->2 g=mol
?-??12 mol Cu 3A 0thi" cannot %e calculated ithout the +nal ma"" o# co!!er) G
Percent Yield
3A 0thi" cannot %e calculated ithout the +nal ma"" o# co!!er)
The li"t o# .uantitati,e o%"er,ation" o%"er,ation" recorded throughout the la%* including including the ma"" o# the %ea9er and the co!!er* a" mea"ured ith a #orce "cale-
J) Anal("i" 1) +alculations a) Calculation Calculation 1 0Ta%le 0Ta%le 4* Ma"" o# Co!!er Be#ore Be#ore Reactant"* Reactant"* 4rd ro) The ma"" o# co!!er co!!er %e#ore %e#ore reactant" reactant" N Mt Mi −
ncertaint( The least count o# the "cale u"ed to mea"ure the co!!er a" ? ??1 g* the uncertaint( a" =$ ?-???> g-
%)
N 35.850 g 35.757 g 0.093g ?-???>g −
=
Calculation / 0Ta%le 4* Initial Mole" o# Co!!er* 1? ro) th
Initial Mole" o# Co!!er N M!0mole" !er co!!er)=Mc 1) / 63.546 63.546 g / mol N 0.093g(1)/ N ?-??12 mole" Cu c) Calculation Calculation 4 0Ta%le 0Ta%le 4* ;inal ;inal Mole" o# o# Co!!er* 11th ro) ;inal Mole" o# Co!!er N M # 0mole" 0mole" !er co!!er)=M c / 63.54 63.546 6 g / mol N Mf / N ;inal Mole" o# Co!!er d) Calculation Calculation 2 0Ta%le 0Ta%le 4* Percent Percentage age Yield* Yield* 1/ th ro) Percen ercentag tage e Yield ield N 0mole" 0mole" o# co!!e co!!err reco reco,er ,ered) ed)=0i =0init nitia iall mole" mole" o# co!!er) ' 1?? N mole" Cu= mole" Cu ' 1?? N 3# = = 3i ' 1?? N Percent Yeild
JI) Conclu"ion
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1) eactions The chemical e.uation" and reaction t(!e" ere ,er( "imilar to hat I initiall( h(!othe"i7ed in "ection I)* /) o# thi" la%* although due to out"ide 9noledge un%e9non"t to me at the time o# the la%* I a" not aare o# a redo' reaction and there#ore the one reaction that largel( dier" #rom m( h(!othe"i" i" reaction A- ;or more in#ormation on the o%"er,ation" cited* !lea"e re#er to "ection IJ)* 1) o# thi" la%a- In reaction reaction A* a#ter a#ter the nitric acid acid a" added added the co!!er* %u%%le" #ormed at the to! o# the "olution hile a ri"e in tem!erature occurred* "igni#(ing that a ga" a" relea"ed 0o%"er,ed a" %eing red=%ron)- @e can in#er that an o'ide a" !roduced 0due to the ri"e in tem!erature and the ga" %eing !roduced) and that due to the change in o'idation "tate" o# the com!ound a redo' reaction occurred and the molecule tran"#ormed %( lo"ing an e$- In thi" reaction* co!!er metal i" added to nitric acid* and react" ith it to !roduce co!!er 0II) nitrate* hile al"o creating nitrogen dio'ide 0the ga" o%"er,ed)* and ater 0hich i" decom!o"ed #rom nitric acid)- The %alanced chemical e.uation #or thi" reaction i" Cu 0") 2H3O40a.) Cu03O4)/0a.) /3O/0g) /H/O0l)%- In reaction reaction B* "odium "odium h(dro h(dro'ide 'ide 03aOH) 03aOH) i" added at room room tem!erature to co!!er0II) nitrate* and the( react to create a %lue* %a"ic !reci!itate- 5ue to the #act that the "olution reacted to create a !reci!itate #rom to com!ound"* a !reci!itation reaction occurred in hich the metal" in co!!er0II) nitrate ere di"!laced to create co!!er0II) h(dro'ide and "odium nitrate- 5ue to #act that Cu0OH) / i" not ea"il( "olu%le* it i" there#ore "olid* hile 3a3O 4 i" a.ueou" %ecau"e hen re#erencing the "olu%ilit( chart* 3O4 i" de"cri%ed a" %eing "olu%le- The %alanced chemical e.uation #or thi" reaction i" Cu03O 4)/0a.) /3aOH0a.) CuOH/0") /3a3O40a.)c- In reaction reaction C* "ince a %lac9* %lac9* !reci!itate !reci!itate a" !roduced !roduced #rom co!!er0II) h(dro'ide* the reaction can there#ore %e cla""i+ed a" a metal h(dro'ide decom!o"ition reaction The co!!er0II) co!!er0II) h(dro'ide h(dro'ide decom!o decom!o"ed "ed to #orm to to com!ound"* co!!er0II) o'ide and ater- The %alanced chemical e.uation #or thi" reaction i" Cu0OH) /0") CuO0") H/O0g)d- In reaction reaction 5* the the !re,iou"l( !re,iou"l( %lac9 "olution "olution turned turned %lue and acidic 0it turned red te"ted on a %lue litmu" !a!er)* "igni#(ing that co!!er0II) o'ide reacted ith the "ul!huric acid to !roduce the acid co!!er0II) "ul!hate and ater* in hich the co!!er and h(drogen ga" re!laced each other* and a dou%le di"!lacement reaction occurredoccurred- The 11
co!!er0II) "ul!hate i" e,identl( a.ueou"* %ecau"e i" a.ueou" %ecau"e hen re#erencing the "olu%ilit( chart* 6O 2 i" de"cri%ed a" %eing "olu%le and i" there#ore ritten a" "uch in the chemical e.uation- The %alanced chemical e.uation #or thi" reaction i" CuO 0") H/6O20a.) Cu6O20a.) H/O0l)e- In the +nal +nal reaction* reaction* a#ter a#ter ?-F g o# 7inc a" a" added to the "olution* the tem!erature o# the mi'ture increa"ed and %u%%le" #ormed at the to! o# the li.uid* meaning a ga" a" relea"ed- Throughout the reaction the 7inc #ormed a ne com!ound ith the "ul!hate and the co!!er remained a" a metal* re"ulting in a "ingle di"!lacement reaction- A ne com!ound* 7inc0II) "ul!hate* a" !roduced* "ince 7inc i" a%o,e co!!er on the acti,it( "erie"- @hen "ul!huric acid a" added to remo,e an( unreacted 7inc* a ne com!ound* 7inc 0II) "ul!hate* a" !roduced "ince 7inc i" a%o,e h(drogen h(drogen on the acti,it( "erie"- The %alanced e.uation #or the "ingle di"!lacement reaction i" Cu6O 20a.) 8n0a) 8n6O20a.) Cu0")- The 7inc0II) "ul!hate %ra9e" u! into 8n6O20a.) H/6O2 8n6O20a.) H/0g)/) +alculations There There are "e,eral "e,eral di"cre!ancie" di"cre!ancie" a" "een "een throughou throughoutt the e'!eriment in relation to the initial and +nal ma""e" o# co!!er* a" ell a" the elementD" initial and +nal mole" 0e,en though due to the lac9 o# data* the +nal ma"" a" not calculated* e ould ha,e #ound that the +nal ma"" o# the co!!er a" le"" than the initial one- I am aare o# thi" due to the la o# con,er"ion o# ma"" la%* e com!leted la"t (ear)- The initial ma"" o# co!!er u"ed in the e'!eriment a" ?-?G4g gram" 0a" demon"trated in Ta%le Ta%le 4)* and the initial initial mole" o# co!!er co!!er a" ?-??12 ?-??12 mole" CuCu5ue to the La o# Con"er,ation o# Ma"" 0a" "ummari7ed in I) 4)* one ould !redict that a#ter an( num%er o# chemical reaction" and !ha"e change"* the +nal ma"" and num%er o# mole" o# co!!er ould remain the "ame a" the initial amount"- A#ter the la% a" +ni"hed* the +nal ma"" o# the co!!er* and the +nal mole" o# the co!!er* although not calculated* ill %e le"" then the initial mole" 0due to a decrea"e in ma"" o# the co!!er)* there#ore it i" in#erred that a ,ariet( o# "ource" o# error too9 !lace throughout thi" la%- The"e error" are e'amined %eloJII) E,aluation %' $rro $rrors rs:: The co!!er co!!er c(cle la% !rocedure !rocedure a" a" de"igned to "er,e the aim" aim" o# the in,e"tigation a" it !ro,ided a "e.uential* li"ted "et o# in"truction" to hich a "tudent a" meant to #ollo- The outlining 1/
o# "te!" a" done in an e:cient and conci"e manner* and greatl( e'!edited the actual e'!erimentation !roce""- Although the la% a" conci"el( outlined* there are "e,eral 9e( element" that needed to %e addre""ed a" to dimini"h the amount o# error" "een throughout thi" la%- Al%eit it i" im!o""i%le to com!letel( remo,e the error" that e e'!erienced in thi" la%* "uch a" !ro%lem" relating to human or random error"* there numerou" minute change" that can %e made a" to de,i"e a "imilar la% ith #eer error"- The "econd "te! o# the la% a" to mea"ure ?-1? g o# co!!er and !lace it in a >? mL %ea9er- A "("tematic error ma( ha,e occurred at thi" "te! i# the %alance that a" u"ed to eight the co!!er a" not cali%rated correctl(* or i# the amount o# co!!er eighed a" not e'actl( the ?-1? g re.uired- E,en a "mall de,iation* "uch a" that o# ?-??g in m( grou!* can in
unintended a"te alread( on the "cale 0hich a" a!!arent hen I conducted the la% a" other grou!" had le#t "e,eral im!uritie" on the "cale)- I ould al"o "ugge"t rin"ing o the "tirring rod ith di"tilled ater %ac9 into the co!!er "olution a" to limit the !o""i%ilit( o# an( e'ce"" co!!er %eing le#t on the rod Thi" i" im!ortant im!ortant due to to the #act that* "ince "ince e e'!erimen e'!erimented ted ith a "mall .uantit( o# co!!er* an( minor amount o# the metal le#t on e'ternal in"trument" ould aect the +nal ma"" and mole" calculated #or the latter- Additionall(* I ould recommend that a !re$determined tem!erature and length o# time to hich the "tudent" "hould heat their "olution" 0in "te! ) %e "et- La"tl(* to manage the error in,ol,ing decanting* I ould "ugge"t that each grou! go through the decanting !roce"" tice 0during the +r"t decanting !roce""* em!t( the li.uid contained in the %ea9er into a "econd* e'ternal container- At thi" !oint the "tudent can decant the
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