,diss]tation pres5t$ = ! degree ( ,doctor ( ,philosophy to ! ,bo>d ( ,univ]sity ,/udies ( ! ,johns ,hopk9s ,univ]sity by ,ar?ur ,john ,hopk9s4 #ahic4 ,ackn[l$gm5t---- ,! "w record$ 9 ?is pap] is ! result ( a sugge/ion giv5 by ,pr(essor ,h4 ,n4 ,morse4 ,x has receiv$ 8 c>eful att5tion ?r\gh\t its c\rse4 ,= 8 in/ruction & exact criticism1 ,i wi% to (f] my ackn[l$gm5t & ?anks4 ,i wi% also to express to ,pr(essor ,ira ,remson my appreciation ( 8 int]e/ & in/ruction & to (f] to ,dr4 ,j4 ,s4 ,ames my ?anks = 8 in/ruction 9 ,physics---- ,table ( ,cont5ts4 ,page4 ,i ,introduction #a ,,ii ,description ( ,app>atus #c ,,iii ,action ( ,manganese ,dioxide on ,potassium ,p]manganate 9 acid solution #i ,,iv ,action ( a ,black ,oxide ( ,manganese on ,potassium ,p]manganate #bd ,v ,! ,am\nt ( ,nitric ,acid ,neutraliz$ #ca ,,vi ,! ,/ability ( ,manganese ,dioxide #cd ,,vii ,! ,effect ( ,v>y+ ,quantities ( ,manganese ,oxide & ,potassium ,p]manganate #ci ,,viii ,! ,r$uction ( ,neutral ,potassium ,p]manganate by ,manganese ,oxide at ,ord9>y ,temp]ature #de ,,ix ,action ( ,potassium ,p]manganate ^u a ,manganese ,oxide ,obta9$ f ,manganese ,dioxide by ,spontane\s ,decomposition #ej ,conclusion ,introduction4 ,! usual laboratory solution ( potassium p]manganate mu/ be frequ5tly re/&>diz$4 ,a slight loss 9 /r5g? may be detect$ aft] /&+ ev5 a few days & ?is *ange becomes m rapid z ! decomposition proce$s4 ,:5 "o looks = ! cause ( ?is increase 9 ! rate ( ! decomposition ( ! p]manganate1 ! att5tion is naturally direct$ to ! br[n manganese oxide :i* sep>ates f ! solution4 ,a desire to asc]ta9 :e!r ! pres5ce ( ?is oxide influ5ces ! rate ( ! decomposition sugge/$ ! exp]im5ts "h describ$4 ,! fact t potassium p]manganate may react ) c]ta9 s-call$ p]oxides ) evolution ( oxyg51 has long be5 kn[n & x appe>$ possible t a simil> reaction may take place betwe5 manganese dioxide & potassium p]manganate4 ,morse & ,all5 inve/igat$ ! reaction betwe5 lead dioxide & potassium p]manganate & !re is embodi$ 9 ,all5's diss]tation#a a /atem5t ( ! e>li] "w 9 ?is l9e ) ref]5ces to ! lit]ature on ! subject4 #a ,johns ,hopk9s ,univ]sity #ahib ,!y h %[n t 9 ! pres5ce ( a quantity ( dilute nitric acid :i* is equival5t to ! potassium 9 ! potassium p]manganate us$1 lead dioxide r$uces ! p]manganate to manganese dioxide )\t itself suff]+ r$uction1 :ile 9 ! pres5ce ( an excess ( /rong] nitric acid1 e4g4 normal to eight normal1 ! lead dioxide is also r$uc$4 ,! foll[+ equations repres5t ! reactions ref]r$ to3 ,i1 :5 ! nitric acid is equival5t to ! potassium 9 ! potassium p]manganate1 #b ,k,mn,o #c ,pb,o ,k,o #c ,pb,o #b ,mn,o #a ,o4 ,,ii1 :5 ! nitric acid is 9 excess1 #b ,k,mn,o #c ,pb,o ,k,o #c ,pb,o #b ,mn,o #c ,o4 ,! r$uc+ action ( manganese dioxide ^u potassium p]manganate 0 suspect$ f ! obs]v$ increase 9 ! rapidity ( ! decomposition ( potassium p]manganate solutions4 ,b only a sugge/ion ( su* a reaction c\ld be f\nd 9 ! lit]ature4 ,?n>d1#b 9 #ahef /ates t manganese dioxide may act ^u potassium p]manganate ei!r z a r$uc+ ag5t1 9 :i* act ! manganese dioxide is *ang$ to a manganate1 or its influ5ce may be catalytic1 caus+ ! evolution ( oxyg54 ,aga9 ,muld]#c 9 #aheh1 ascrib$ ! decomposition ( potassium p]manganate solutions to ! pres5ce ( "s potassium manganate4 #b ,comptes ,r5dues #db1 #chb #c ,jahresb]i*t #aheh p4 #eha ,x c\ld n be asc]ta9$ t any inve/igation ( ?is matt] _h ev] be5 und]tak54 ,x 0 !re=e decid$ to /udy ! "q & x appe>$ t ! mo/ satisfactory evid5ce c\ld be obta9$ by measur+ ! quantity ( oxyg5 :i* is evolv$ :5 potassium p]manganate & manganese dioxide are br\ght toge!r4 ,description ( ,app>atus4 ,! app>atus#d employ$ 9 ?is "w consi/s ( f\r p>ts3 8#a7 a flask1 ,a1 9 :i* ! reactions 7 conduct$4 ,a melt+ po9t bulb ( ab\t #dj cc4 capacity1 ! diamet] ( its neck be+ #bj mm41 0 us$ = ?is purpose4 #d ,?is app>atus 0 us$ by ,all5 & describ$ by him4 ,i wi% to ackn[l$ge my indebt$ness to him = ! illu/ration & description giv5 "h :i* is tak5 by p]mission ^w = ^w f 8 diss]tation4 ,illu/ration ,?is 0 clos$ ) a two-hole rubb] /opp]1 ?r\gh "o hole ( :i* pass$3 #b7 ,a small glass tube1 ,,bb1 runn+ up f ! flask ab\t #dj cm41 & !n b5t twice at "r angles4 ,"o limb ( ?is tube 0 surr\nd$ by a small ,liebig's cond5s]1 :ile ! %ort] turn$ d[n to meet-- #c7 a ,s*iff's azotomet] fill$ ) m]cury & connect$ at its top ) ! tube above m5tion$4 ,9 practice x 0 f\nd desirable to h a little wat] on ! top ( ! m]cury column4 #d7 ,?r\gh ! second hole ( ! rubb] /opp] clos+ ! flask 0 pass$ a %ort piece ( glass tub+ b5t obliquely j above ! /opp] & tightly connect$ ) a rubb] tube ab\t #ej cm4 long1 ,,dd4 ,?is tube 0 clamp$ ne> its l[] end ) a ,mohr's p9*-cock1 :ile ! upp] 0 connect$ ) ! /em ( a small funnel1 ,f4 ,:5 an exp]im5t 0 to be conduct$1 ! azotomet] ,c1 0 connect$ to ! tube1 ,b1 & ti$ tightly1 a piece ( good rubb] tub+ be+ us$ = ! connection4 ,! res]voir ( ! azotomet]1 ,m1 0 !n rais$ until ! m]cury _h driv5 out all ! air 9 ,c1 & ! /op-cock clos$4 ,next ! funnel ,f 0 fill$ ) wat]1 ! p9*-cock clos+ ,d op5$ & ! wat] all[$ to fl[ d[n & drive out all ! air 9 ! tube4 ,! latt] 0 !n clamp$ & ?us kept full ( wat]4 ,! app>atus be+ n[ ready1 ! flask ,a1 conta9+ ! sub/ances 9 ! desir$ quantity1 0 made fa/ to ,b & ,d by means ( its /opp]4 ,! /op-cock ( ,c op5$4 ,! flask ,a 0 heat$ 9 a wat]-ba? = any desir$ "t1 ! oxyg5 be+ collect$ 9 ,c z fa/ z x 0 giv5 (f4 ,at ! end ( ! exp]im5t1 all ! gases :i* rema9$ 9 ,a & ,b 7 driv5 ov] into ,c by l[]+ ! res]voir ,m & op5+ ! p9*-cock at ,d4 ,:5 ?is 0 accompli%$ ! /op-cock ( ,c 0 clos$ & ! gases br\ght "u atmosph]ic pressure by br++ ! m]cury 9 ,c & ,m to ! same level4 ,x w be se5 t 9 ?is gas volume 0 includ$ ! air :i* ,a & ,b conta9$ at ! beg9n+ ( ! exp]im5t4 ,! oxyg5 evolv$ f ! cont5ts ( ! flask 0 det]m9$ ?us3 ,aft] read+ (f ! total volume ( air & oxyg5 & r$uc+ to normal conditions1 ! total volume ( oxyg5 0 obta9$ by absorption ) phosphorus or pyrogallol1 & f ! residual nitrog5 c\ld be calculat$ f ! volume ( air to be d$uct$ ! total volume ( gases4 ,! rema9d] is ! volume ( oxyg5 s\ght40 ,action ( manganese dioxide on potassium p]manganate 9 acid solution4 ,?ree sets ( app>atus l ! "o describ$ 7 us$4 ,! flask ( app>atus ,no4 ,i conta9$ manganese dioxide & dilute nitric acid4 ,! flask ( app>atus ,no4 ,,ii conta9$ potassium p]manganate & dilute nitric acid4 ,! flask ( app>atus ,no4 ,,iii conta9$ potassium p]manganate & dilute nitric acid & manganese dioxide4 ,! manganese dioxide us$ 9 ^! exp]im5ts 0 precipitat$ f a solution ( potassium p]manganate by a dilute solution ( mangan\s sulfate 9 ! mann] describ$ on page #cd & !n wa%$ & dri$ at #ajj;,c4 ,an illu/ration ( ! proportions 9 :i* ! diff]5t sub/ances 7 br\ght toge!r 9 ea* ( ! ?ree flasks is to be f\nd 9 ! foll[+ /atem5t ( ! quantities us$ 9 ! fir/ exp]im5t4 ,! v>iations f ^! proportions occurr+ 9 subsequ5t exp]im5ts are not$ 9 ! table giv+ ! summ>y ( ! results4 ,usually ab\t #aej m4g4 ( manganese dioxide 7 us$ & ! solutions 9 ! ?ree flasks 7 br\ght to ! same volume by addition ( di/ill$ wat]4 ,exp]im5t ,no4 ,i ,flask ,no4 ,i ,manganese dioxide #aej m4g4 ,n_/#aj nitric acid #ad4bh c4c4 ,mn4 9 ,k,mn,o 9 ,no4 ,,ii or ,no4 ,,iii ,wat]1 #bg4ab c4c4 ,total solution #da4dj c4c4 ,flask ,no4 ,,ii ,potassium p]manganate1 #bj c4c4 #aab4dh m4g4 ,k,mn,o4 ,n_/#aj nitric acid #g4ad c4c4 ,k 9 ,k,mn,o ,wat]1 #ad4bf c4c4 ,total solution #da4dj c4c4 ,flask ,no4 ,,iii ,potassium p]manganate1 #bj c4c4 #aab4dh m4g4 ,k,mn,o4 ,n_/#aj nitric acid #ba4dj c4c4 ,k ,mn 9 ,k,mn,o ,manganese dioxide #aej m4g4 ,! nitric acid 9 ,no4 ,i is calculat$ to be ! same z t rema9+ free aft] ! potassium ( ! p]manganate 9 ,no4 ,,iii has be5 neutraliz$4 ,x w be cle> t ! quantities ( free nitric acid are ! same 9 flask ,no4 ,i & 9 flask ,no4 ,,iii provid$ ! potassium ( ! p]manganate is appropriat$ by ! nitric acid4 ,moreov] ea* flask conta9s ! same quantity ( manganese dioxide & ! volume ( ! liquid is ! same 9 bo?4 ,on ! o!r h& flask ,no4 ,,iii conta9s p]manganic acid4 ,?is arrangem5t 0 select$ 9 ord] to det]m9e h[ f> ! evolution ( oxyg5 0 influ5c$ by ! action ( nitric acid on ! manganese dioxide or by ! spontane\s decomposition ( p]manganic acid4 ,x 0 ?\ght t if m oxyg5 %\ld be obta9$ f flask ,no4 ,,iii conta9+ a mixture ( p]manganate1 manganese dioxide & nitric acid1 ?an f mixtures ,no4 ,i & ,no4 ,,ii1 ! l>g] volume mu/ be due to ! r$uction ( ! p]manganate by ! manganese oxide4 ,! ?ree flasks aft] hav+ be5 fill$ z describ$ 7 atta*$ to ! app>atus & !n all subm]g$ to ! same dep? 9 ! boil+ wat] ( a s+le glass wat]-ba?4 ,! /op-cocks ( ! azotomet]s 7 !n op5$ & ! m]cury all[$ to fall to )9 ab\t fifty millimetres ( its level 9 ! res]voirs4 ,?is diff]5ce 9 level 0 ma9ta9$ z ne>ly z practicable by l[]+ ! res]voirs comm5s]ably ) ! increase 9 gas volume4 ,no action c\ld be obs]v$ 9 flasks ,no4 ,i & ,no4 ,,ii dur+ ! :ole c\rse ( ! exp]im5t4 ,! cont5ts ( flask ,no4 ,,iii h[ev] gave (f bubbles ( oxyg5 imm$iately1 ! m]cury fell 9 ! azotomet] & ! d>k purple ( ! p]manganate solution 9 flask ,no4 ,,iii became rapidly light]4 ,)9 ab\t five m9utes x 0 r$uc$ to a delicate p9k b ?is t9t p]si/$ = ab\t t5 m9utes :5 x also disappe>$4 ,imm$iately aft] ! disappe>ance ( ! p]manganate color ! solution 0 fill$ ) a br[n oxide :i* rema9$ = ab\t ?irty five m9utes :5 x subsid$ leav+ ! sup]natant liquid cle>4 ,not)/&+ ! fact t ! color ( ! p]manganate _h entirely disappe>$ & ! susp5d$ oxide _h subsid$ )9 an h\r aft] beg9n+ ! exp]im5t1 ! flasks 9 ! e>li] exp]im5ts 7 all[$ to rema9 = two h\rs long]4 ,by admitt+ di/ill$ wat] ?r\gh ! tube ,d see figure ! gas 0 !n =c$ ov] into ! azotomet]4 ,f9ally1 ! oxyg5 0 det]m9$ 9 ! mann] previ\sly describ$4 ,! foll[+ illu/ration f ! fir/ exp]im5t may s]ve to %[ ! me?od ( calculat+ ! results4 ,i ,,ii ,,iii ,total air & oxyg5 #db4fj c4c4 #eb4dj c4c4 #fj4fj c4c4 ,nitrog5 aft] absorption ( oxyg5 #cd4jj c4c4 #dj4ij c4c4 #cg4hj c4c4 ,oxyg5 #h4fj c4c4 #aa4ej c4c4 #bb4hj c4c4 ,air #gi4h nitrog5 #bj4b oxyg5 ,oxyg5 ( air #bj4b -------------- ---- #h4fj c4c4 #aj4cec c4c4 #i4eg c4c4 ,nitrog5 f\nd #gi4h ,oxyg5 obta9$ #j4j #a4adg c4c4 #ac4bc c4c4 ,temp]ature #ba;,c4 ,b>omet] #gcg mm4 ,oxyg5 obta9$ at ,normal #j #a4jcc c4c4 #aa4iac c4c4 ,! #bj c4c4 ,k,mn,o #aab4dh m4g4 #a atom ( oxyg5 #g4ifg c4c4 ,atoms oxyg5 f\nd ,i ,,ii ,,iii f ! molecule ,k,mn,o #j #j4abi #a4dif ,z at ! end ( ! prec$+ calculation ! results are express$ 9 ! table foll[+ 9 t]ms ( oxyg5 atoms obta9$ f ea* molecule ( potassium p]manganate ,k,mn,o r$uc$4 ,?us an equival5t ( "o atom ( oxyg5 f "o molecule ( potassium p]manganate w\ld equal #ae4if_/aeg4fg ( ! weight ( potassium p]manganate us$ 9 ! exp]im5t4 ,?is weight divid$ by ! weight ( "o cubic c5timetre ( oxyg5 gives ! numb] ( cubic c5timetres ( oxyg5 at normal1 equival5t to "o atom ( oxyg5 f "o molecule ( potassium p]manganate4 ,! results obta9$ are tabulat$ z foll[s3 ,?ree-h\r det]m9ations4 ---------------------------------------- -------------------------- ,flask ,i ,flask ,,ii ,flask ,,iii ---------------------------------------- -------------------------- ,mn,o ,n_/#aj ,,hno ,k,mn,o ,n_/#aj ,,hno ,k,mn,o ,n_/#aj ,,hno #aej m4g4 ,no4 ( #bj c4c4 ,no4 ( #bj c4c4 ,no4 ( molecules #aab4dh m4g4 molecules #aab4dh m4g4 molecules ---------------------------------------- -------------------------- #a #j4jj #b #j4ac #a #a4die #c #b #j4jj 0 8 #a #a4dic 0 #c 0 #j4ac #c #a4ecb99 0 #d #j4jj 0 #j4ba 0 #a4dff 0 #e #j4jc 0 #j4aj 0 #a4dfg 0 #f #j4jb 0 #j4be 0 0 #g #j4jf 0 #j4jh 0 #a4ebf99 0 #h #j4jd 0 #j4ae 0 #a4ebg 0 #i #j4jd 0 #j4aa 0 #a4ejd 0 #aj 0 #j4bj 0 #a4ejd 0 #aa #j4jc 0 #j4ad 0 #a4eaf 0 #ab #j4jj 0 #j4ah 0 #a4ebd 0 #ac #j4jc 0 #j4be 0 #a4eei99 0 #ad #j4je 0 #j4bf 0 #a4egd 0 #ae #j4jb #a #j4cb #b #a4eeb #b #af #j4jc 0 #j4ca 0 #a4ehc8 0 #ag #j4jd 0 #j4ca 0 #a4eab 0 #ah #j4ja 0 #j4cb 0 #a4dff 0 #ai #j4jj 0 #j4ah 0 #a4dab 0 #bj #j4ja 0 #j4cf 0 #a4daa 0 #ba #j4jf 0 #j4bb 0 #a4djb 0 #bb #j4jj 0 #j4cj 0 #a4die99 0 #bc #b #j4jh #c #a4dfi #c #e;,fifty m9ute det]m9ations #bd #j4jd #a #j4jf #b #a4efd #b #be #j4jd 0 #j4aa 0 #a4dia 0 #bf #j4je 0 8 0 #a4eab 0 #bg #j4jc 0 #j4je 0 #a4ecb 0 #f;,fifte5 m9ute det]m9ations #bh #j4je #a #j4jh #b #a4cdj #b #bi #j4jd 0 #j4je 0 #a4cbe 0 #cj #j4jf 0 #j4je 0 #a4cce 0 #ca #j4jj 0 #j4jj 0 #a4cdg 0 #cb #j4jc 0 #j4jc 0 #a4dab 0 #cc #j4jb #b #j4jb #c #a4cfc #c #cd #j4jb 0 #j4jf 0 #a4cgg 0 #ce #j4jj 0 #j4jb 0 #a4cfc 0 #e ,?is m>k$ ! "t :5 ! oxides fir/ settl$1 leav+ a colorless sup]natant liquid4 #f ,?is m>k$ ! "t :5 ! solution 0 fir/ decoloriz$4 ,inspection ( ! table w %[ t :e!r ! oxyg5 7 det]m9$ imm$iately aft] ! subsid5ce ( ! oxides 7i4e4 aft] fifty m9utes7 or aft] ?ree h\rs ! results obta9$ are practically ! same4 ,! t5d5cy ( ! potassium p]manganate to lose /r5g? made ! frequ5t prep>ation ( new samples advisable4 ,:]ev] a new sample has be5 us$ 9 ! c\rse ( ! exp]im5ts1 ! fact has be5 not$ 9 ! table by an a/]isk4 ,x w be notic$ t :]e a new solution is us$ ! figures = flask no4 ,,iii are imm$iately l>g] & ne>] to "o & "o half atoms ( oxyg5 f ea* molecule ( potassium p]manganate4 ,a phosphorus gas-pipette 0 us$ = ! absorption ( ! oxyg5 9 all ! exp]im5ts ! results ( :i* are embodi$ 9 ! =ego+ table4 ,9 subsequ5t exp]im5ts an alkal9e solution ( pyrogallol 0 employ$4 ,x is n[ kn[n t ! v>iation 9 ! composition ( ! manganese oxide 9 use _h "s influ5ce ^u ! results4 ,x has also be5 f\nd t ! manganese dioxide prep>$ by ! r$uction ( p]manganate by manganese sulphate is mu* less /able ?an 0 suppos$ at ! "t ?is "w 0 begun4 ,! dioxide prep>$ 9 ?is way beg9s imm$iately to lose oxyg5 spontane\sly b recov]s ! same 9 ! pres5ce ( an excess ( potassium p]manganate4 ,9 ! light ( ^! facts x is easy to und]/& :y l[] results 7 obta9$ :5 ! oxyg5 0 det]m9$ imm$iately aft] ! disappe>ance ( ! color ( ! p]manganate & be=e ! susp5d$ oxide _h subsid$4 ,x appe>s t ! manganese oxide employ$ 9 ^! exp]im5ts 0 n1 z 0 suppos$ at ! "t1 ! dioxide b "o conta9+ a small] proportion ( oxyg54 ,if su* is ! case ! fir/ action ( ! p]manganate ^u x w\ld be to replace ! oxyg5 :i* _h be5 lo/4 ,! r$uction ( ! rema9+ p]manganate w\ld !n probably be 9 accordance ) ! equation1 #b ,k,mn,o #c ,mn,o #b ,k,o #e ,mn,o #a ,o ,at ! "t :5 ! p]manganate color disappe>s1 all ( ! manganese is 9 ! dioxide condition & ! fur!r evolution ( oxyg51 :i* is %[n by ! prec$+ exp]im5ts to take place dur+ ! subsid5ce ( ! susp5d$ oxides1 is due to a p>tial r$uction ( ?is manganese4 ,!re=e ! relation ( ! r$uction ( ! manganese oxide bel[ ! ,mn,o condition be=e ! treatm5t ) p]manganate to ! r$uction :i* foll[s ! disappe>ance ( ! p]manganate color w det]m9e :e!r ! oxyg5 evolv$ %all be m or less ?an "o & "o half atoms to ea* molecule ( p]manganate4 ,nei!r v>iations 9 ! quantities ( nitric acid us$ 7f two to ?ree molecules 9 ,no4 ,,iii7 nor ! v slight v>iations 9 ! am\nt ( manganese dioxide us$1 seem to affect appreciably ! am\nt ( oxyg5 obta9$4 ,x appe>s t ! action ( manganese dioxide on potassium p]manganate is ! same z t ( lead sup]oxide#g 9 ! pres5ce ( v dilute nitric acid4 ,bo? r$uce x to manganese dioxide ) ! evolution ( "o & "o half atoms ( oxyg5 to ea* molecule ( ! p]manganate4 #g ,all5's !sis4 ,! evolution ( oxyg5 f flask ,no4 ,i conta9+ manganese dioxide & nitric acid is v slight4 ,f flask ,no4 ,,ii conta9+ potassium p]manganate & "o equival5t nitric acid1 x is also slight b usually great] ?an f flask ,no4 ,i4 ,! diff]5ces are mu* great] 9 ! case ( ^? det]m9ations 9 :i* ! heat+ ( ! flask 0 cont9u$ = ?ree h\rs & 9 ?is fact is to be f\nd fur!r evid5ce ( ! r$uc+ action ( manganese dioxide on potassium p]manganate4 ,! possibility ( a reaction analog\s to t betwe5 potassium p]manganate & lead dioxide 9 ! pres5ce ( /rong nitric acid seems to be exclud$ by ! fact t ! high] oxides ( manganese may be prep>$ 9 ! pres5ce ( conc5trat$ nitric acid4 ,action ( a ,black ,oxide ( ,manganese on ,potassium ,p]manganate4---- ,z an analysis ( ! manganese dioxide %[$ ! probable pres5ce ( "s manganese 9 ! mangan\s condition1 a sample 0 treat$ on ! wat]-ba? = "s days ) dilute nitric acid :ile di/ill$ wat] 0 add$ f "t to "t to keep ! dilution ne>ly con/ant4 ,?is 0 done = ! purpose ( det]m9+ :e!r ! mangan\s manganese might n be extract$ 9 ! =m ( manganese nitrate4 ,! light br[n oxide :i* 0 us$ 9 ! previ\s exp]im5ts _h be5 prep>$ by add+ a dilute solution ( mangan\s sulphate to a hot solution conta9+ potassium p]manganate 9 excess & dilute nitric acid4 ,no analysis ( ! oxide ?us prep>$ 0 made at ! "t ( its prep>ation1 b x has be5 %[n by ! "w ( o!rs t ! oxide mu/ h _h at t "t a composition z reg>ds ! relation ( manganese to oxyg51 v ne>ly equival5t to t ( ,mn,o4 ,dur+ ! c\rse ( ! exp]im5ts previ\sly record$1 a det]m9ation ( ! ratio ( ! manganese to ! available oxyg5 9 ! comp\nd 0 made & f\nd to be z #a4jc 3 #a4jj ,! sub/ance gave #ed4fi p]c5t manganese & #ae4dd p]c5t available oxyg54 ,a second analysis made "s weeks lat] gave a ratio ( manganese to available oxyg5 ( #a4jf3 #a4jj4-- ,! sub/ance gave #ed4gf p]c5t manganese #ae4jb 0 available oxyg54 ,! manganese 0 det]m9$ by ! me?od ( ,gibbs#h & ! available oxyg5 by oxalic acid & potassium p]manganate4 #h ,silliman's ,am4 ,j4 ,sci5ce 7#b7 #dd4baf ,x 0 ?is oxide :i* 0 treat$ ) nitric acid 9 ! mann] describ$4 ,9 ! c\rse ( ?is treatm5t ! light br[n color *ang$ to black & ! oxide became heavi]4 ,! dilute nitric acid 9 :i* ! oxide _h be5 dige/$ 0 f\nd to conta9 mangan\s manganese1 b analysis ( ! black product %[$ t ! oxide _h suff]$ a /ill fur!r r$uction4 ,! ratio ( manganese to available oxyg5 0 f\nd to h ris5 f #a4jf3 #a4jj to #a4aeg3 #a4jjj4 ,! analytical data are giv5 bel[3-- ,! sub/ance gave #fj4di p]c5t manganese #fj4df 0 0 & #ae4bc p]c5t oxyg5 #ae4ai 0 0 ,?is ratio w\ld correspond v ne>ly to a comp\nd hav+ ! composition ,mn,o#f,mn,o b x is by no means c]ta9 t ! r$uc+ action ( nitric acid 0 f9i%$4 ,! action ( ?is oxide on potassium p]manganate 0 det]m9$ "u ! same conditions z 9 ! case ( ! br[n oxide z describ$ on page #ad4 ,! foll[+ illu/ration ( ! proportions us$ is tak5 f ! fir/ exp]im5t4 ,exp]im5t ,no4 ,i ,flask ,no4 ,i ,manganese oxide1 black1 #aej m4g4 ,n_/#aj nitric acid #ad4ic c4c4 ,mn 9 ,k,mn,o 9 ,no4 ,,ii or ,no4 ,,iii ,wat] #bg4df c4c4 ,total solution #db4ci c4c4 ,flask ,no4 ,,ii ,potassium p]manganate #bj c4c4 #aag4ga m4g4 ,n_/#aj nitric acid #bb4ci c4c4 ,k & ,mn 9 ,k,mn,o ,total solution #db4ci c4c4 ,flask ,no4 ,,iii ,potassium p]manganate #bj c4c4 #aag4ga m4g4 ,n_/#aj nitric acid #bb4ci c4c4 ,k & ,mn 9 ,k,mn,o ,manganese oxide1 black #aej m4g4 ,total solution #db4ci c4c4 ,! fir/ two results are f exp]im5ts 9 :i* ! action 0 /opp$ at ! fir/ loss ( ! color ( potassium p]manganate4 ,! la/ two are ! results f exp]im5ts 9 :i* ! action 0 /opp$ aft] ! oxide _h settl$ leav+ a cle> colorless sup]natant liquid4 ,! am\nt ( oxyg5 giv5 (f 9 any "o case is express$ 9 ! table z ! numb] ( atoms ( oxyg5 d]iv$ f ea* molecule ( potassium p]manganate1 z foll[s3 ,a ,n_/#aj nitric acid4 ,no4 ( molecules4 ---------------------------------------- ----------------------- ,flask ,i ,flask ,,ii ,flask ,,iii ---------------------------------------- ----------------------- ,black ,potassium ,potassium oxide ,a p]manganate ,a p]manganate ,a #aej m4g4 #bj c4c4 #bj c4c4 #aag4ga m4g4 #aag4ga m4g4 ---------------------------------------- ----------------------- #a #b h\rs4 #j4jj #b #j4ah #c #a4ccg #c #b #b h\rs #j4jb 0 #j4bd 0 #a4cce 0 #c #b h\rs #j4jb 0 #j4dd 0 #a4djb 0 #d #d h\rs #j4jj 0 #j4ee 0 #a4cfb 0 ,! volume ( ! oxyg5 evolv$ is consid]ably small] ?an t obta9$ :5 ! br[n oxide 0 us$4 ,x is nev]!less l>g] ?an c\ld h be5 evolv$ if all ( ! manganese _h be5 left 9 ! dioxide condition at ! close ( ! exp]im5t4 ,?is fact indicates t !re 0 a slight r$uction ( ! manganese dioxide aft] ! disappe>ance ( ! color ( ! p]manganate4 ,t su* a r$uction ( manganese dioxide does take place w be made app>5t by a comp>ison ( ! results ( ! fir/ two exp]im5ts 9 :i* ! oxyg5 0 measur$ soon aft] ! color ( p]manganate _h disappe>$1 ) ! results ( ! la/ two exp]im5ts 9 :i* ! oxyg5 0 det]m9$ aft] a long] int]val4 ,x w be notic$ 9 ?is z 9 ! s]ies ( exp]im5ts ) ! br[n oxide t ! rate ( ! evolution ( oxyg5 lib]at$ 9 flask ,no4 ,,ii increases ) ! "t ( heat+4 ,! ,am\nt ( ,nitric ,acid neutraliz$4 ,a few exp]im5ts 7 made to det]m9e h[ mu* nitric acid is neutraliz$ "u ! conditions :i* prevail$ 9 ! =ego+ exp]im5ts4 ,i4 ,! flask conta9$ br[n oxide #aej m4g4 ,n_/#aj nitric acid #f4ih c4c4 & 0 heat$ = ?ree h\rs 9 ! wat]-ba?4 ,acid neutraliz$ #d4ea c4c4 #fd4fj p]c5t4 ,,ii4 ,! flask conta9$ br[n oxide #aej m4g4 ,n_/#aj nitric acid #f4ih c4c4 & 0 heat$ = #ej m9utes 9 ! wat]-ba?4 ,acid neutraliz$ #c4ji c4c4 #dd4bj p]c5t4 ,,iii4 ,! flask conta9$ br[n oxide #aej m4g4 ,n_/#aj nitric acid #g4df c4c4 & 0 heat$ = fifty m9utes 9 ! wat]-ba?4 ,acid neutraliz$ #c4af c4c4 #db4cj p]c5t4 ,,iv4 ,! flask conta9$ br[n oxide #aej m4g4 ,n_/#aj nitric acid #g4df c4c4 & 0 heat$ = #ae m9utes 9 ! wat]-ba?4 ,acid neutraliz$ #b4gf c4c4 #cg4j p]c5t ,v4 ,! flask conta9$ br[n oxide #aej m4g4 potassium p]manganate #bj c4c4 #aab4dh m4g4 ,n_/#aj nitric acid #f4ih c4c4 7 #b molecules = ea* molecule ( ,k,mn,o7 & 0 heat$ = ?ree h\rs 9 ! wat]-ba?4 ,acid neutraliz$ #j4ce c4c4 #e4j p]c5t4 ,,vi4 ,repetition ( ,no4 ,v4 ,acid neutraliz$ #j4dd c4c4 #f4c p]c5t4 ,,vii4 ,! flask conta9$ br[n oxide #aej m4g4 potassium p]manganate ! same z 9 numb]s ,v & ,,vi & 0 heat$ = #ae m9utes 9 ! wat]-ba?4 ,acid neutraliz$ #e4b p]c5t4 ,,viii4 ,repetition ( ,no4 ,,vii ,acid neutraliz$ #d4j p]c5t ,,ix4 ,! flask conta9$ black oxide #aej m4g4 ,n_/#aj nitric acid #ad4ic c4c4 & 0 heat$ = two & "o f\r? h\rs 9 ! wat]-ba?4 ,acid neutraliz$ #d4hg c4c4 #cb4df p]c5t4 ,x4 ,repetition ( ,no4 ,,ix4 ,acid neutraliz$ #ch4aj p]c5t4 ,,xi4 ,! flask conta9$ black oxide #aej m4g4 potassium p]manganate #bj c4c4 #agg4ga m4g41 ,n_/#aj nitric acid #bb4ci c4c4 7 #b molecules = ea* molecule ( ,k,mn,o7 & 0 heat$ f\r & "o half h\rs 9 ! wat] ba?4 ,acid neutraliz$ #ajj4jj p]c5t4 ,no def9ite conclusions c be drawn f ^! neutralization exp]im5ts s9ce x is well kn[n t manganese oxides prep>$ z 7 ^? us$ 9 ^! exp]im5ts always conta9 "s1 ?\gh probably n a con/ant quantity ( alkali4 ,x is /at$ by ,bemmel5#i t manganese dioxide decompos$ ! salts ( ! alkalies ) lib]ation ( acid4 #i ,j4 fr ,prak4 ,*4 7#b7 #bc1 #cbd-cgi4 ,! ,/ability ( ,manganese ,dioxide4 ,hav+ f\nd 9 ! c\rse ( ! "w already describ$ t manganese dioxide prep>$ 9 ! wet way is mu* less /able ?an 0 suppos$1 x 0 decid$ to make "s exp]im5ts ^u ! spontane\s decomposition :i* x und]goes4 ,to ?is end a fre% sample 0 prep>$ 9 ! foll[+ mann]4 #aj grams ( potassium p]manganate 7 dissolv$ 9 #ejj c4c4 ( di/ill$ wat] & ! solution all[$ to settle = "o day4 ,! liquid 0 !n filt]$ ?r\gh glass wool1 heat$ to #fe;,c4 & treat$ ) #cbj c4c4 ,n_/#aj nitric acid1 hav+ also a temp]ature ( #fe;,c4 #bj4e grams ( mangan\s sulphate dissolv$ 9 #b4e litres ( wat] heat$ to #fe;,c1 7 n[ add$1 ) /irr+1 to ! acidifi$ solution ( potassium p]manganate4 ,! precipitate 0 all[$ to settle & ! sup]natant liquid :i* /ill reta9$ ! p]manganate color1 decant$4 ,! residue 0 !n treat$ ) wat]1 /irr$ & all[$ to settle4 ,! wat] 0 decant$ & ! oxide filt]$4 ,! filt] us$ consi/$ ( two plat9um cones betwe5 :i* 0 plac$ a small pap] filt] :i* did n q rea* to ! edge ( ! out] cone4 ,?is filt] 0 plac$ 9 ! bottom ( a glass funnel & ! oxide p\r$ ^u x4 ,! oxide 0 repeat$ly wa%$ ) di/ill$ wat] & !n transf]r$ to a por\s plate4 ,x 0 aft]w>ds heat$ = sev]al h\rs to a temp]ature ( #fe;,c4 ,at ?is temp]ature x 0 f\nd impracticable to br+ ! oxide to a con/ant weight1 b ?is fact 0 no s]i\s ob/acle 9 ! way ( ! subsequ5t "w s9ce x 0 only desir$ to asc]ta9 :at *anges take place 9 ! ratio ( ! manganese to ! available oxyg54 ,! manganese 0 det]m9$ by ! me?od ( ,gibbs & ! available oxyg5 by oxalic acid & potassium p]manganate4 ,an analysis ( ! oxide made %ortly aft] its prep>ation 9 ! mann] describ$1 gave #ea4ih p]c5t ,manganese #ea4hf pr4 ct4 #ea4gd 0 #ad4hcf p]c5t ,oxyg5 #ad4hcg 0 #ad4hci 0 %[+ a ratio ( manganese to available oxyg5 ( #a4jah 3 #a4jjj4 ,! above analysis 0 made ,may #a1 #ahib4 ,! oxide 0 !n plac$ 9 a glass-/opp]$ weigh+ bottle & all[$ to /& until ,novemb]4 ,an analysis made on ! t5? day ( ! latt] mon? gave a ratio ( manganese to available oxyg5 ( #a4aih 3 #a4jjj correspond+ v closely to a composition ,mn,o#e,mn,o1 9 :i* ! calculat$ ratio is #a4bjj 3 #a4jjj ,six mon? lat] 7,april #bj1 #ahic7 an analysis ( ! same mat]ial %[$ a ratio ( manganese to available oxyg5 ( #a4cjj 3 #a4jjj ,?is result 0 confirm$ ,m ,walk] :o made repeat$ analyses ( ! sub/ance at ! same "t4 ,ano!r sample ( manganese oxide 0 prep>$ 9 ! same mann] z t us$ 9 ! previ\s exp]im5ts & plac$ "u wat]4 ,an analysis made aft] ,eight days gave a ratio ( ,mn 3 available ,o #a4jac 3 #a4jjj ,tw5ty 0 0 0 0 0 0 0 0 #a4jcg 3 #a4jjj ,=ty ?ree 0 0 0 0 0 0 0 0 #a4jdj 3 #a4jjj ,! results "h record$ cle>ly indicate t ! br[n oxide ( manganese :i* is prep>$ by ! r$uction ( potassium p]manganate by manganese sulphate und]goes a spontane\s decomposition involv+ a loss ( oxyg54 ,?is loss ( oxyg5 or ! effect ( v>y+ conditions ^u ?is decomposition ( manganese dioxide is n[ be+ inve/igat$ by ,m ,walk] ( ?is laboratory4 ,! ,effect ( ,v>y+ ,quantities ( ,manganese ,oxide on ,potassium ,p]manganate4 ,! foll[+ exp]im5ts 7 made = ! purpose ( det]m9+ ! effect ( v>y+ quantities ( manganese oxide on ! "t requir$ = ! r$uction ( potassium p]manganate4 ,a4 ,9 ! pres5ce ( nitric acid4 ,! ratio ( manganese to available oxyg5 9 ! mat]ial us$ = ^! exp]im5ts 0 det]m9$ & f\nd to be #a4jah 3 #a4jjj ,! exp]im5ts 7 conduct$ aft] ! same mann] z ^? previ\sly describ$4 ,diff]5t portions ( ! manganese oxide 7 weigh$ out & treat$ 9 ! flasks us$ 9 ! previ\s exp]im5ts ) ! quantities ( p]manganate :i* 7 f\nd by calculation to h ! desir$ molecul> ratios to ! oxide4 ,a quantity ( ,n_/#aj nitric acid equival5t to ! potassium ( ! potassium p]manganate 0 add$4 ,! flasks 7 !n imm]s$ 9 ! ba? ( boil+ wat] & ! "t requir$ = ! disappe>ance ( ! p]manganate color not$4 ,! ratios ( ! oxide to ! p]manganate & ! times requir$ = ! r$uction ( ! latt] are embodi$ 9 ! foll[+ table4 ,molecul> ,ratio ,oxide to ,k,mn,o #a3a #b3a #c3a #d3a #e3a #f3a #g3a ,"t ( decolorization 9 m9utes #a 0 #abj #fh #b 0 #aaj #fe #c 0 #aej #fe #d 0 #aej #hj #e 0 #abj #ge #f 0 #abj #ge #g 0 #age787 #gh #ec #h 0 #afj #gi #ed #i 0 #ade #da #cj #aj 0 #abj #ej #cf #aa 0 8 #dg #cb #ab 0 #aaj #cg #cj #ac 0 #fd #ajbj787 #bj787 #ad 0 #gb #e787 #e787 #ae 0 #he #e787 #e787 #aj ,decoloriz$ be=e "t 0 tak54 ,! results appe>+ 9 ! table on ! same horizontal l9es are ^? ( exp]im5ts made simultane\sly1 t is1 ! flasks 9 ^! exp]im5ts 7 imm]s$ at ! same "t & 9 ! same wat]-ba?4 ,^!1 t is ! results appe>+ on ! same horizontal l9e1 & ^! only are comp>able1 s9ce x 0 f\nd t v slight diff]5ces 9 ! temp]ature ( ! ba? 7 ( great influ5ce on ! l5g? ( "t requir$ = ! r$uction ( ! p]manganate4 ,x is cle> t ! rate ( ! r$uction ( ! p]manganate is greatly increas$ by increas+ ! quantity ( ! manganese oxide4 ,aft] r$uction ( ! p]manganate1 ! cont5ts ( ! flasks 7 9 e case filt]$ & ! filtrate te/$ by ,crum's reaction = ! pres5ce ( manganese4 ,no manganese 0 f\nd4 ,! abs5ce ( manganese 9 ! filtrate %[s t ! r$uction ( ! p]manganate 0 n due to ! =mation ( manganese nitrate1 ?\gh x w be cle> f ! results ( subsequ5t exp]im5ts t ! pres5ce ( nitric acid ex]ts an influ5ce on ! rate ( ! r$uction4 ,b4 ,9 neutral solution4 ,! condition 7 ! same z "u ,a1 except t ! nitric acid 0 omitt$4 ,^? flasks conta9+ potassium p]manganate & "o1 two & sev5 molecul> equival5ts respectively ( ! manganese oxide 7 imm]s$ 9 ! wat]-ba? z be=e4 ,no4 ,i conta9+ "o molecule ( oxide & "o molecule ,k,mn,o 0 r$uc$ 9 #eg h\rs ,no4 ,,ii conta9+ two molecules ( oxide & "o molecule ,k,mn,o 0 r$uc$ 9 #ce h\rs ,no4 ,,iii conta9+ sev5 molecules ( oxide & "o molecule ,k,mn,o 0 r$uc$ 9 #b h\rs ,c4 ,9 alkal9e solution4 ,! conditions 7 ! same z "u ,b1 except t five molecules ( potassium hydroxide 7 add$ = ea* molecule ( ! p]manganate4 ,no4 ,i conta9+ "o molecules ( oxide = ea* molecule ,k,mn,o 0 r$uc$ 9 #ia h\rs4 ,no4 ,,ii conta9+ two molecules ( oxide = ea* molecule ,k,mn,o 0 r$uc$ 9 #ee787 h\rs4 ,no4 ,,iii conta9+ sev5 molecules ( oxide = ea* molecule ,k,mn,o 0 r$uc$ 9 #aj h\rs4 ,x appe>s t potassium p]manganate is less easily r$uc$ by manganese oxide 9 neutral ?an 9 acid solutions & 9 alkal9e t 9 neutral solutions4 ,! ,r$uction ( ,neutral ,potassium ,p]manganate by ,manganese ,oxide at ,ord9>y ,temp]ature4 ,9 ^! exp]im5ts1 ! manganese oxide us$ 0 prep>$ 9 ! same mann] z t 9 :i* ! proportion ( manganese to available oxyg5 0 f\nd imm$iately aft] its prep>ation to be #a4jah 3 #a4jjj ,x 0 dri$ = sev]al days at #fe;,c41 b = almo/ a mon? aft] its prep>ation 0 n us$4 ,h5ce1 :at ! ratio ( ! manganese to ! oxyg5 at ! "t :5 ! p]manganate 0 treat$ ) x1 is q unc]ta94 ,x h[ev] appe>s probable f ! subsequ5t exp]im5ts on ! in/ability ( manganese dioxide at #fe;,c4 t ! ratio ( manganese to available oxyg5 mu/ h be5 at ab\t #a4je3 #a4jj correspond+ to a =mula ,mn,o#bj,mn,o4 ,two solutions ( p]manganate 7 made1 filt]$ ?r\gh glass wool & /&>diz$4 ,solution ,a4 ,a cubic c5timetre ( ?is 0 f\nd to be equival5t to #e4bgh m4g4 iron 9 ! f]r\s condition4 ,solution ,b4 ,a cubic c5timetre ( ?is 0 f\nd to be equival5t to #ad4cgi m4g4 iron 9 ! f]r\s condition4 ,?ree #bej c4c4 portions ( ea* ( ! solutions ,a & ,b 7 plac$ 9 clean glass-/opp]$ bottles4 ,^! bottles 7 labell$ 8a01 8a0 & 8a0 8b01 8b0 & 8b04 8a0 conta9$ #bej c4c4 potassium p]manganate ea* cubic c5timetre ( :i* 0 equival5t to #e4bgh m4g4 ,fe4 ,x 0 clos$ & put away 9 ! d>k & all[$ to /& f ,june f\rte5? until ! f\rte5? ( ! foll[+ ,octob]4 ,its /r5g? 0 !n det]m9$ & f\nd to h decl9$ #j4gb p]c5t4 8a0 conta9$ ! same quantity ( ! same p]manganate solution z 8a0 & x 0 clos$ on ! same date & plac$ 9 mildly diffus$ light until ,octob] f\rte5?4 ,an analysis on ! latt] date %[$ t its /r5g? _h also decl9$ #j4gb p]c5t4 8a0 conta9$ ! same quantity ( ! same p]manganate solution z 8a0 & 8a0 & to ?is 0 add$ #j4e gram ( ! manganese oxide previ\sly ref]r$ to4 ,! bottle 0 !n clos$ & plac$ 9 diffus$ light beside 8a04 ,an analysis1 ,octob] f\rte5? %[$ t its /r5g? _h decl9$ #cd4fb p]c5t4 8b0 conta9$ potassium p]manganate ea* cubic c5timetre ( :i* 0 equival5t to #ad4cgi m4g4 ,fe4 ,x 0 clos$ & put away 9 ! d>k beside 8a04 ,an analysis ,octob] f\rte5? %[$ t its /r5g? _h decl9$ #a4ga p]c5t4 8b0 conta9$ ! same quantity ( ! same p]manganate z 8b04 ,x 0 clos$ & plac$ 9 mildly diffus$ light beside 8a04 ,an analysis ,octob] f\rte5? %[$ a decl9e 9 /r5g? ( #b4da p]c5t4 8b0 conta9$ ! same quantity ( ! same p]manganate z 8b0 & 8b04 ,to x 0 add$ #j4e grams ( ! manganese oxide4 ,! bottle 0 clos$ & plac$ 9 diffus$ light beside 8a01 8a01 & 8b04 ,an analysis1 ,octob] f\rte5? %[$ a decl9e 9 /r5g? ( #gh4hf p]c5t4 ,! conclusions to be drawn f ! =ego+ results are 7#a7 t dilute solutions ( potassium p]manganate are m /able bo? 9 diffus$ light & 9 d>kness ?an ! m conc5trat$ ones1 & 7#b7 t ! pres5ce ( manganese oxides ha/5 to an enorm\s degree ! r$uction ( potassium p]manganate ev5 at summ] temp]atures4 ,x w also be obs]v$ t ?is r$uc+ action ( ! manganese oxide is great] 9 ! /rong] ?an 9 ! m dilute solutions4 ,x %\ld be rem>k$ t ! summ] ( #ahib 9 :i* ^! exp]im5ts 7 made1 0 "o ( unusual heat4 ,action ( ,potassium ,p]manganate ^u a ,manganese ,oxide ,d]iv$ f ,manganese ,dioxide by ,spontane\s ,decomposition4 ,! oxide us$ 9 ^! exp]im5ts 0 "o :i* _h be5 prep>$ 9 ! mann] h]et(ore describ$ by add+ manganese sulphate to an excess ( potassium p]manganate4 ,soon aft] its prep>ation ! ratio ( manganese to available oxyg5 9 x 0 f\nd to be #a4jah 3 #a4jjj ,at ! "t :5 x 0 us$ 9 ^! exp]im5ts1 ! ratio ( manganese to available oxyg5 0 f\nd to be #a4aih 3 #a4jjj ,correspond+ v ne>ly to ! ratio ( manganese to available oxyg5 9 ,mn,o#e,mn,o4 ,exp]im5t ,i4 #bcj m4g4 ( ! oxide 0 treat$ ) ! quantity ( p]manganate calculat$ to be necess>y = its oxidation to manganese dioxide4 ,! mixture 0 kept at a temp]ature ( #bb;,c4 until ! color ( ! p]manganate disappe>$4 ,?is requir$ ab\t t5 h\rs4 ,an analysis ( ! oxide !n gave a ratio ( manganese to available oxyg5 #a4jbg 3 #a4jjj ,exp]im5t ,,ii ,a repetition ( exp]im5t ,i4 ,an analysis ( ! oxide aft] decolorization ( ! p]manganate gave a ratio ( manganese to available oxyg5 ( #a4jbb 3 #a4jjj ,exp]im5t ,,iii ,! conditions are ! same z 9 ! prec$+ exp]im5ts except t twice ! am\nt ( p]manganate calculat$ = ! conv]sion ( ! oxide into manganese dioxide 0 add$4 ,an analysis ( ! residue aft] decolorization gave a ratio ( manganese to available oxyg5 ( #j4iid 3 #a4jjj ,exp]im5t ,,iv ,a repetition ( exp]im5t ,,iii4 ,an analysis ( ! residue gave a ratio ( manganese to available oxyg5 ( #j4iie 3 #a4jjj ,exp]im5t ,v ,a repetition ( exp]im5ts ,,iii & ,,iv4 ,! ratio ( manganese to available oxyg5 9 ! residue 0 #j4iie 3 #a4jjj4 ,! =ego+ results indicate 7exp]im5ts ,,iii1 ,,iv1 & ,v7 t ! oxyg5 lo/ spontane\sly by manganese dioxide prep>$ 9 ! wet way1 is fully recov]$ :5 ! r$uc$ oxide is treat$ ) excess ( potassium p]manganate4 ,! ratio ( ! manganese to ! available oxyg5 0 det]m9$ 9 ! foll[+ mann]4 ,! cont5ts ( ! flask 7 filt]$ ?r\gh asbe/os & ! flask & ! precipitate wa%$ ) cold wat]4 ,! cont5ts ( ! filt] 7 !n return$ to ! flask & treat$ ) an excess ( a /&>d solution ( oxalic acid & dilute sulphuric acid4 ,aft] r$uction ! excess ( ! oxalic acid 0 det]m9$ by a /&>d solution ( potassium p]manganate4 ,! solution 0 !n filt]$1 well wa%$ & ! manganese 9 ! filtrate precipitat$ by ! me?od ( ,gibbs4 ,f ! total am\nt ( manganese f\nd1 !re 0 d$uct$ ! quantity :i* 0 introduc$ 9 det]m9+ ! excess ( oxalic acid by potassium p]manganate4 ,summ>y ( ,conclusions-- ,i ,potassium p]manganate 9 weakly acid1 9 neutral1 & 9 alkal9e solutions1 is r$uc$ by manganese dioxide :i* has be5 prep>$ 9 ! wet way1 ) evolution ( "o & "o half atoms ( oxyg5 = ea* molecule ( ! p]manganate4 ,9 o!r words1 ! p]manganate is r$uc$ to manganese dioxide4 ,,ii ,?is r$uction is mo/ rapid 9 acid & sl[e/ 9 alkal9e solutions4 ,,iii ,! rate ( r$uction is greatly increas$ by increas+ ! proportion ( manganese dioxide4 ,,iv ,9 conc5trat$ solutions ( potassium p]manganate1 ! r$uction by manganese dioxide is relatively m rapid ?an 9 dilute4 ,v ,manganese oxide1 prep>$ 9 ! wet way i4e4 by ! addition ( manganese sulphate to a hot solution conta9+ an excess ( p]manganate1 has ! composition ,mn,o z reg>ds ! ratio ( manganese to available oxyg54 ,,vi ,?is oxide is un/able4 ,x loses oxyg5 spontane\sly ev5 at ord9>y temp]atures4 ,,vii ,! oxyg5 :i* is ?us lo/ is recov]$ :5 ! oxide is aga9 treat$ ) an excess ( potassium p]manganate4 ,,viii ,x is sugge/$ t a p>tial explanation ( ! r$uction ( potassium p]manganate by manganese oxide may be f\nd 9 ! in/ability ( ! latt]2 9 o!r words t ! r$uction may consi/ 9 alt]nate r$uction & reoxidation processes4 ,b :5 ! rapidity ( ! r$uction is tak5 into acc\nt1 x seems probable t a reaction analog\s to t betwe5 p]manganic acid & hydrog5 sup]oxide mu/ also take place4 ,ar?ur ,john ,hopk9s 0 born ,septemb] #bj1 #ahfd 9 ,bridgewat]1 ,massa*usetts4 ,receiv+ 8 prep>ation = college 9 ! public s*ools ( t t[n1 he ent]$ ,amh]/ ,college 9 #ahha & graduat$ ) ! degree ( ,a4 ,b4 9 #ahhe4 ,! five ye>s foll[+ 7 sp5t 9 tea*+ 9 ! ,/ates ( ,massa*usetts & ,new ,york4 ,he ent]$ ! ,johns ,hopk9s ,univ]sity 9 #ahij1 0 assi/ant 9 ! quantitative laboratory ( t univ]sity dur+ ! academic ye> ( #ahia-ib1 & ! foll[+ ye> 0 appo9t$ ,fell[ 9 ,*emi/ry4