4 dang toan vo co 12 on thi dhcd

7/28/2019 4 Dang Toan Vo Co 12 on Thi DHCD

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Bin son v ging dy : Thy gio Nguyn Minh Tun THa Trng THPT Chuyn Hng Vng Ph Th

Trn bc ng thnh cng khng c du chn ca kli bing 1

MC LCTrang

Li gii thiu 2

Phn 1: Gii thiu 4 chuyn ha i cng v v c 12 11

Chuyn 1 :i cng v kim loi 11

Chuyn 2 :Kim loi kim, kim loi kim th,nhm 82

Chuyn 3 :Crom, st, ng, niken, ch, km,vng, bc, thic 210

Chuyn 4 : Phn bit mt s cht v c,chun dung dch, ha hc v vn pht trin kinh t, x hi, mi trng 296

Phn 2 : p n 318


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Trn bc ng thnh cng khng c du chn ca kli bing2

Li gii thiuTgii thiu

H v tn : Nguyn Minh Tun

Gii tnh : Nam

Ngy, thng, nm sinh : 31 05 1980Trnh vn ha : 12/12

Trnh chuyn mn : C nhn Sinh Ha

Tt nghip HSP H Ni 2 thng 06 2002

Hin l gio vin ging dy b mn ha hc

Ngy vo ngnh : 31 12 2002

Ngy vo ng : 29 12 2009

Ngy vo ng chnh thc : 29 12 2010

i ch nh ring :

Snh 16 T9A Khu 5 Phng Gia Cm Vit Tr Ph ThSin thoi : 01689 186 513a ch email : [email protected]

a ch facebook: nguyn minh tun (Vit Tr) -http://www.facebook.com/nguyen.minhtuan.1650?sk=wall

Cc trng tng cng tc :

Trng THPT Phng X (t thng 09 2002 n 04 2003)

Trng THPT Xun ng (t thng 04 2003 n 08 2007)

Trng THPT Chuyn Hng Vng (t thng 09 2007 n nay)


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B ti liu n thi i hc, cao ng mn ha hcB ti liu trc nghim n thi i hc, cao ng mn ha hc do thy bin son gm 12 quyn :

Quyn 1 : Gii thiu7 chuyn ha hc 10

Quyn 2 : Gii thiu3 chuyn ha hc i cng v v c 11

Quyn 3 : Gii thiu6 chuyn ha hc hu c 11

Quyn 4 : Gii thiu4 chuyn ha hc hu c 12

Quyn 5 : Gii thiu4 chuyn ha hc i cng v v c 12

Quyn 6 : Gii thiu11 phng php gii nhanh bi tp ha hc

Quyn 7 : Gii thiu40 luyn thi trc nghim mn ha hc

Quyn 8 : Hng dn gii7 chuyn ha hc 10

Quyn 9 : Hng dn gii3 chuyn ha hc i cng v v c 11

Quyn 10 : Hng dn gii6 chuyn ha hc hu c 11

Quyn 11 : Hng dn gii4 chuyn ha hc hu c 12

Quyn 12 : Hng dn gii4 chuyn ha hc i cng v v c 12


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Nhng iu thy mun ni :

iu thnht thy mun ni vi cc em rng : la tui ca cc em, khngc vic g l quan trng hn vic hc tp. Hy cgng ln cc em nh, tng lai cacc em ph thuc vo cc em y.

iu thhai thy mun ni rng : Nu cc em c mt c m trong sng thng v nhng kh khn trc mt m tb n. Thy tng cc em cu chuyn diy (do thy su tm), hi vng cc em shiu c gi tr ca c m.

i bng v G

Ngy xa, c mt ngn ni ln, bn sn ni c mt t chim i bng. Trong t c bn qu

trng ln. Mt trn ng t xy ra lm rung chuyn ngn ni, mt qu trng i bng ln xung vri vo mt tri g di chn ni. Mt con g mi tnh nguyn p qu trng ln y.

Mt ngy kia, trng nra mt ch i bng con xinh p, nhng bun thay ch chim nh cnui ln nh mt con g. Chng bao lu sau, i bng cng tin n ch l mt con g khng hnkhng km. i bng yu gia nh v ngi nh ang sng, nhng tm hn n vn khao kht mtiu g cao xa hn. Cho n mt ngy, trong khi ang chi a trong sn, i bng nhn ln triv thy nhng ch chim i bng ang si cnh bay cao gia bu tri.

" - i bng ku ln - c g ti c th bay nh nhng con chim ".

By g ci m ln: "Anh khng th bay vi nhng con chim c. Anh l mt con g v gkhng bit bay cao".

i bng tip tc ngc nhn gia nh tht s ca n, m c c th bay cao cng h. Mi lni bng ni ra m c ca mnh, by g li bo n iu khng th xy ra. l iu i bng cuicng tin l tht. Ri i bng khng m c na v tip tc sng nh mt con g. Cui cng, saumt thi gian di sng lm g, i bng cht.

Trong cuc sng cng vy: Nu bn tin rng bn l mt ngi tm thng, bnssng mt cuc sng tm thng v v, ng nh nhng g mnh tin. Vy th, nubn tng m c tr thnh i bng, bn hyeo ui c m ... v ng sngnh mt con g!


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Chng trnh n thi i hc cao ng mn ha hc

Mn ha hc lp 10

Chuyn s Tn chuyn Sbui hcn tp ha hc 9 05

01 Nguyn t 06

02 Bng tun hon cc nguyn t ha hc v nh lut tun hon 05

03 Lin kt ha hc 05

04 Phn ng ha hc 10

05 Nhm halogen 07

06 Nhm oxi 07

07 Tc phn ng ha hc v cn bng ha hc 05

50 bui

Mn ha hc lp 11

Chuyn s Tn chuyn Sbui hc01 S in li 06

02 Nhm nit 06

03 Nhm cacbon 03

04 i cng ha hu c 06

05 Hirocacbon no 05

06 Hirocacbon khng no 10

07 Hirocacbon thm 04

08 Dn xut halogen. Ancol Phenol 10

09 Anehit Xeton Axit cacboxylic 10

60 bui


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Mn ha hc lp 12

Chuyn s Tn chuyn Sbui hc01 Este Lipit 07

02 Cacbohirat 0303 Amin Amino axit Protein 07

04 Polime Vt liu polime 03

05 i cng v kim loi 07

06 Kim loi kim Kim loi kim th Nhm 10

07 Crom, st, ng v mt s kim loi khc 10

08 Phn bit mt s cht v c. Ha hc v vn pht trinkinh t, x hi v mi trng

05

52 bui

Phng php gii nhanh bi tp ha hc

Chuyn s Tn chuyn Sbui hc01 Phng php ng cho 02

02 Phng php t chn lng cht 02

03 Phng php bo ton nguyn t 02

04 Phng php bo ton khi lng 02

05 Phng php tng gim khi lng, s mol, th tch kh 02

06 Phng php bo ton electron 02

07 Phng php quy i 02

08 Phng php s dng phng trnh ion rt gn 02

09 Phng php bo ton in tch 02

10 Phng php s dng cc gi tr trung bnh 02

20 bui

luyn thi trc nghim mn ha hc

Mi bui hc cha 02 , 40 cha trong 20 bui.


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Hnh thc hc tpHc theo tng chuyn , mi chuyn ng vi mt chng trong sch gio khoa, quy trnh

hc tp nh sau :+ Tm tt l thuyt c bn ; ch trng, khc su kin thc trng tm m thi thng hay

khai thc.

+ Phn dng bi tp c trng, c cc v d minh ha.+ Cung cp h thng bi tp trc nghim theo cu trc : L thuyt trc, bi tp sau. Cc bi

tp tnh ton c chia theo tng dng hc sinh d dng nhn dng bi tp v p dng phngphp gii cc v d mu vo cc bi tp ny nhm rn luyn v nng cao knng gii bi tp.

+ Cung cp h thng p n chnh xc hc sinh kim tra, nh gi kt qu hc tp camnh.

+ i vi nhng bi tp kh, hc sinh khng lm c, thy s hng dn gii bng nhiucch sau cht li cch ngn gn nht (khong t 1 n 10 dng).

+ Sau mi chuyn s c mt bi kim tra trn lp, thng qua kt qu ca bi kim tra nh gi, xp loi, pht hin ra nhng im mnh v im yu ca tng hc sinh. Trn c s,s pht huy nhng im mnh v khc phc nhng im yu ca cc em nhm mc ch quan trngnht l nng cao thnh tch hc tp cho cc em.

Lu : i vi mt s em sinh dthi khi A, B v nhng l do no , n hthc k 1 ca lp 12 m kin thc ha hc cn yu, khng p ng yu cu thi ihc, cao ng th c thn thy xin theo hc ly li kin thc. i vi cc emhc sinh nh vy thy sc mt chng trnh ringkm cp cc em trong khong40 bui :

Hai cng v v c hc20 bui.Ha hu c hc 20 bui.

Sau 40 bui hc cc em s ly li c nhng kin thc c bn nht v kt quim thi i hc mn ha hc ca cc em s t c khong t 5 n 6 im hocc th hn mt cht, tt nhin t c iu th cc em phi hc tp tht snghim tc theo ng nhng hng dn ca thy. V tnh cht c bit nn nhng lphc ny ch khong 1 n 5 hc sinh.

Tchc lp hc

- a ch t chc lp hc :Tng 2 Snh 16 T9A Khu 5 Phng Gia Cm VitTr (pha trong khu th Trm So).


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Nhng nghch l ny ang din ra hng ngy xung quanh bn

Bn c phi l ngi yu qu v quan tm n sc khe ca bn thn v ngi thn ca mnh haykhng? Bn c thy xung quanh v ngay trong bn thn chng ta y ry nhng nghch l m taang sng chungv ht thnh khng kh vy?

Chng ta c nhiu tin hn xa, nhng sc khe km hn.Cc hiu thuc v bnh vin nhiu hn, nhng chng ta vn khng khe, m cng phi n nhngni thng xuyn hn.Chng ta thy nhiu cng trnh p hn, nhng cc bnh vin th cng qu ti v trthnh nim nh khng khip hn.

Con ci chng ta c chm sc nhiu hn, nhng chng dbm vkm thch nghi hn.Chng ta lo lng v chun b rt nhiu iu cho tng lai xa xi n nhng th nh nht hin ti,nhng li rt t ch n iu quan trng nht l sc kheca chng ta ngay by gi.Chng ta th vi sc kheca mnh, mc c th ca ta ln ting bo ng ht ln ny n ln

khc qua nhng triu chng v cn au, nhng i tra du v sa cha ngay cho chic xekhi n kuct kt.Khi cn tr tin gi gn v nng cao sc khe, chng ta mc cvi chnh c th mnh tng ng,nhng sn sng tr rt nhiu tin cho cc bc sv ch hiu thuc xa l mong ly li sc khe mt.Chng ta sn sng tr rt nhiu tin cho nhng tin nghi snh iu, hng hiu, c sn,... nhiu khich tm ta c tha mn v hnh din vi ngi khc, m chng t hi xem iu c thc smang li sc khe, sminh mn cho tr c v bnh an cho tm hn mnh hay khng.Chng ta khng tm hiu trn trng, yu qu v bo v c th ca mnh - mt b my v cngtinh t v k diu ca t nhin qua hng triu nm tin ha, m tin tng v ph thc hon tonvo nhng ngi c danh hiu bc s, thc s, tin s, trng khoa, m kin thc ca h mi chnh a tr trc s b n k diu v vi ca s sng.

Bn c nhn thyiu ny khng?Nu l ti sn qu gi, tin bc th ta gi trong kt bo mt trong ngi nh ca ta, hoc nhng nian ton nht.Cn sc khe c th - ni tr ng ca linh hn, th ta trao vo tay v ph thc cho nhng "nhchuyn mn v y t": Bc s- Hiu thuc - Bnh vin,... Ta ph thc cho nhng hng kinh doanh n nhanh, ru bia, nc ngt, nh hng, qun bia, cm bi,... V c nhng phng tin truynthng ch bit doanh s v li nhun, nhng lung gi d lun khen, ch, tt, xu m chng bitthc s chng thi v u!

Tht au lng, c nhng ngi u m bn 1 qu thn ly 40 triu ng, liu c ngi tr giqu thn ca bn bao nhiu th bn s bn? 1 t, 2 t, hay 3 t? Nu tnh c c th l con ngi bn,c phi bn ang shu mt ti sn v gi m chng th no mua c, v cng chng ai c th

bn cho bn?

Chng ta sng st hoc th nghe tin nhng ngi quen b bnh nng sp t gi ci i, nhngkhng bao ginghmnh hoc ngi thn thit ca mnh cng c th nh vy.Chng ta biu l v thng cm, an i, ng vin v biu qu cho nhng ngi au bnh, nhngchng cm nhn v rt ra c iu g tni au n m hang phi chu. Chng ta mc nhinv d dng chp nhn mt thc t l mnh chng gip g c, ngoi mt cht tin dnh tr cho

bc sv hiu thuc.


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Chng ta ving m tang nhng ngi thn, ngi quen nh mt th tc phi lm, nhng khngbao gi nghn mnh v nhng ngi thn yu nht cng s l nhn vt chnh ca mt m tang,vo mt ngy no . V quan trng hn l lm cch no trnh xa ci ngy khng mong muny?Chng ta v tht thuc l, ung ru bia, nhi nht nhng th c hi vo c th mnh, mc d

bit chng c hi. Chng ta coi ru bia l thc o ca sc khe v phong hnh din v tho, s v t bn cht ca tnh bng hu!Chng ta tu cchnh tm tr mnh bng cch ho hng tm kim v nhi nht vo tm tr mnhnhng tin gy sc, v n, t nn, nhng th m chnh chng ta cm ght, gin d

Nhiu ngi trong chng ta mua vui, gii trt nhng vic lm m ta lun phi tm cch giu kntrc nhng ngi m ta tn trng, hoc phi xu h vi lng tm ca mnh (nu cha t la dimnh rng iu l ng n).

Chng ta vn hi h ngy m trong vng xoy kim tin, say sa tch ly ca ci, hnh din vnhng ti sn v danh vng ca mnh. Cng c nhiu, chng ta cng mun nhiu hn.i khi chng ta khng quan tm nhng vic ta lm c hi cho x hi v nhng ngi xung quanh

hay khng, v khng cn bit hu qu. V chng ta nghrng, nu c th nhng ngi xa lkhcch khng phi ta v ngi thn yu ca ta, s phi gnh chu nhng thti t!Bn ang bc bi v iu g? nhim v khi bi, rc, nc thi quanh nh bn?

Nn tc ng v tai nn giao thng rnh rp trn mi no ng?

Bnh vin qu ti, gi thuc "ct c", bc sv trch nhim v nn phong b?

Thc phm ngy cng t v nhim hn lun e da sc khe ca gia nh, con ci bn?

T nn x hi ang rnh rp lm h hoi nhng a con ca bn?

Nhng mi quan h phc tp, k, ghen ght hay nhng mu mm ni lm vic?

...Nhng th ny ang hng ngy, hng gihy hoi sc khev ly i nhng gi tr cao qu cacuc sng m ng l bn phi c.Chng ta rt ght nhng iu xy n vi mnh.

Nhng i lc chnh chng ta cng gp la thm vo, hoc hng li t nhng iu !

Bn c t hi: l s v trch nhim, th, hay s bt lc ca chnh chng ta?

iu quan trng hn, sv trch nhim ang ngy cng trthnh thng xuyn hn - n nitr thnh mt thi quen v lan ra c cng ng (ri t cng ng li len li v ng trtrong chnh ngi nh ca ta), v lm cho i sng ca chng ta ngy cng nhim, ngt ngtv bc bi hn na.

Chng ta c tng (v hy vng) rng nhng iu xui xo, vn hn ch n vi nhng ngi khc,m khng th n vi mnh, cha m v con ci mnh.Hoc chng ta lun lo lng, shi v nhng iu xu s xy n, nhng li ch lo tch ly tin bc i ph vi chng. V chng ta vn ngh c nhiu tin l c th mua c tt c!Hoc nhiu ngi li i lo cu cng ng b, lm mm cao c y l Pht, dng sao gii hn mongtrnh c tai qua nn khi, m khng bit rng Lut Nhn - Qu ph trm v tr.

Ngi ang sng khng dm nhn trch nhim lm ch v nh ot cuc i mnh, m li hyvng da dm, ph thccho nhng ngi khut ni?Vi sc khe, chng ta cth v lnh lng c th ca mnh bo ng v ku cu ht ln nyn ln khc, bng nhng cn au m , hoc thong qua.

Chng ta mun khai thc c th mnh nh th vi mt kn lkhng cng, hoc c xe min ph,m ch cn cho n t thc n, thm ch c nhng th c hi- nu l nhng th a thch ca ta.Bi v ta thy nhiu ngi xung quanh cng lm nh vy!


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Cho n khi, bnh tt vtai ha p trn u ta, trong ngi nh ca ta, ln b, m, v, chng, conci ca ta.Ta au kh, ta ku cu, ta cu khn, ta li, ta hi hn v tic nui.Ta cho l iu xui xo, l s phn, l nh mnh ca ta. ng thi, v chnh ta to ra s phn ,

bng nhng s la chn v hnh ng ca ta hng ngy, hng gi.

Bn c dp him hoi no bnh cnh v lng nghe nhng ngi ang sp tgi ci i? Bn cbit hmongc iu g nht? C phi h ao c kim c nhiu tin hn? C c chc v vdanh vng ln hn? c nhiu ngi bit n v ni ting hn?

Hay h kht khao c sng thm vi ngy khe mnh?Hoc mong c thit tha li mt iu g thc sc ngha cho cuc i?Bn ang nm trong tay nhng iu . Nhng c l bn sp nh mt, nu bn vn lm nhnhng g m hm qua bn vn lm, nh a s mi ngi xung quanh chng ta vn lm mt cch mlm.

Nh c t Lai Lt Ma ni: iu lm Ngi ngc nhin nht nhn loi chnh l con ngi."Bi v con ngi dng sc khe tch ly tin bc, ri li dng tin bc mua li sc khe. Con

ngi mi sng vi qu khv lo cho tng lai m qun mt hin ti, n ni khng sng chochin ti ln tng lai.Con ngi sng nh thskhng bao gi chtNhng ri scht nh cha tng sng bao gi!Hy suy nghli v nhng g ang xy ra xung quanh bn, trong tm tr bn!Sc khe, Hnh phc v ngha cuc sng nm trong tay bn. Tt c ph thuc vo sthc tnhv hnh ngca bn, ngay tby gi!Vy chng ta cn phi lm g?Chng ta c nn thng trng ch vo s ci thin ca h thng y t, gio dc, vo lc lngqun l th trng, vo h thng quy hoch giao thng, mi trng, ri bao nhiu h thng khcna? V khi khng tha mn th chng ta ch bit ln ting than vn, ch bai, ch trch?Con ng ci bin thgii tht n gin, nh mt cu ni ca mt bc vnhn: ng gin dv chin u vi bng m, hy thp ln mt ngn la d nh.Trc ht, mi ngi hy t tm bin php bo v sc khe ca chnh bn thn v gia nh mnh.Bn phi l ngi gn gi ly mt trong nhng ti sn qu nht ca chnh mnh - sc khe. ngnn trao n vo tay ngi khc.Hy bit tinh lc nhng g tt p vo trong tm hn mnh v trao truyn cho th h con ci chngta. mi v tr cng vic trong cuc sng, chng ta u c thnh hng n nhng con ngi,mi trng xung quanh bng chnh t tng, li niv hnh ngca mnh. s l nhng ngnla nh, nhiu ngn la s thp sng cho mt cuc sng mi.

Hy lm mt con ngi theo ng ch NHN, nh li Khng T dy: iu mnh khngmun th ng em n cho kkhc, iu g mnh mun th nn gip ngi t c.Gieo g gt ny, iu c bit hn l khi gieo 1 s gt c gp 10 ln. Nhiu ngi cng gieo htging tt th s c ma bi thu. Nu bn l ngi u tin gieo ht, bn s l tm gng, ng lokhng c ai lm theo bn, v bn s vn l CON NGI.

Nu bn thy nhng thng tin ny c ch, hy chia s v gi tng cho nhng ngi m bn yu qunh mt mn qu, thng ip ny c th truyn i mi, cho mt x hi mnh khe, sng sut vnhn i hn!Tht may mn cho ti gp v thay i suy nghgip ti tm li cho mnh sc khe tngchng mt i. Hnh phc li mt ln na mm ci vi gia nh ti .

Sc kho tuy cha phi l tt cnhng nu khng c sc khoth nhng thcn li u mtht ngha


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PHN 1 : GII THIU 4 CHUYN HA I CNG V V C 12

CHUYN 1: I CNG V KIM LOIBI 1 : TNH CHT CHUNG CA KIM LOI. HP KIM

A. L THUYTI. V tr v cu to1. V tr ca kim loi trong bng tun hon

Cc nguyn t ho hc c phn thnh kim loi v phi kim. Trong s 110 nguyn t ho hc bit c ti gn 90 nguyn t l kim loi. Trong bng tun hon cc nguyn t kim loi c mt :

- Nhm IA (tr hiro) v IIA.- Nhm IIIA (tr bo) v mt phn ca cc nhm IVA, VA, VIA.

- Cc nhm B (t IB n VIIIB).

- H lantan v actini, c xp ring thnh hai hng cui bng.

2. Cu to ca nguyn tkim loiNguyn t ca hu ht cc nguyn t kim loi u c t electron lp ngoi cng (1, 2 hoc 3e).

V d : Na : 1s22s22p63s1 ; Mg : 1s22s22p63s2 ; Al : 1s22s22p63s23p1

Trong cng chu k, nguyn t ca nguyn t kim loi c bn knh nguyn t ln hn v intch ht nhn nh hn so vi nguyn t ca nguyn t phi kim. V d xt chu k 2 (bn knh nguyn

tc biu din bng nanomet, nm) :11Na 12Mg 13Al 14Si 15P 16S 17Cl

0,157 0,136 0,125 0,117 0,110 0,104 0,099

3. Cu to tinh thkim loiHu ht cc kim loi iu kin thng u tn ti di dng tinh th (tr Hg).

Trong tinh th kim loi, nguyn t v ion kim loi nm nhng nt ca mng tinh th. Ccelectron ho tr lin kt yu vi ht nhn nn d tch khi nguyn t v chuyn ng t do trongmng tinh th.

a s cc kim loi tn ti di ba kiu mng tinh th ph bin sau :

a. Mng tinh thlc phngTrong tinh th, th tch ca cc nguyn t v ion kim loi chim 74%, cn li26% l cc khe rng. Thuc loi ny c cc kim loi : Be, Mg, Zn,...

b. Mng tinh thlp phng tm dinCc nguyn t, ion kim loi nm trn cc nh v tm cc mt ca hnh

lp phng.

Trong tinh th, th tch ca cc nguyn t v ion kim loi chim 74%,

cn li 26% l cc khe rng. Thuc loi ny c cc kim loi : Cu, Ag, Au,Al,...


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c. Mng tinh thlp phng tm khi Cc nguyn t, ion dng kim loi nm trn cc nh v tm ca hnh

lp phng.

Trong tinh th, th tch ca cc nguyn t v ion kim loi ch chim68%, cn li 32% l cc khe rng. Thuc loi ny c cc kim loi : Li, Na,

K, V, Mo,...

4. L in kt kim loiLin kt kim loi l lin kt c hnh thnh gia cc nguyn tv ion kim loi trong mng tinh

thdo stham gia ca cc electron tdo.I I. Tnh cht vt l ca kim loi1. Tnh cht vt l chunga. Tnh do

Khc vi phi kim, kim loi c tnh do : D rn, d dt mng v d ko si. Vng l kim loi c

tnh do cao nht, c th dt thnh l mng n mc nh sng c th xuyn qua.Kim loi c tnh do l v cc ion dng trong mng tinh th kim loi c th trt ln nhau ddng m khng tch ra khi nhau nhnhng electron t do chuyn ng dnh kt chng vi nhau.

b. Tnh dn inKhi t mt hiu in th vo hai u dy kim loi, nhng electron t do trong kim loi s

chuyn ng thnh dng c hng t cc m n cc dng, to thnh dng in.Kim loi dn in tt nht l Ag, sau n Cu, Au, Al, Fe,...

Nhit ca kim loi cng cao th tnh dn in ca kim loi cng gim do nhit cao, ccion dng dao ng mnh cn trdng electron chuyn ng.

c. Tnh dn nhitTnh dn nhit ca cc kim loi cng c gii thch bng s c mt cc electron t do trong

mng tinh th.Cc electron trong vng nhit cao c ng nng ln, chuyn ng hn lon v nhanh chng

sang vng c nhit thp hn, truyn nng lng cho cc ion dng vng ny nn nhit lantruyn c t vng ny n vng khc trong khi kim loi.

Thng cc kim loi dn in tt cng dn nhit tt.

d. nh kimCc electron t do trong tinh th kim loi phn x hu ht nhng tia sng nhn thy c, do

kim loi c v sng lp lnh gi l nh kim.Tm li : Tnh cht vt l chung ca kim loi nh ni trn gy nn bi sc mt ca cc

electron tdo trong mng tinh thkimloi.2. Tnh cht vt l ring

Ngoi nhng tnh cht vt l chung kim loi cn c mt s tnh cht vt l ring nh khi lngring, nhit nng chy, tnh cng Nhng tnh cht ny ph thuc vo bn lin kt kim loi,nguyn t khi, kiu mng tinh th, ca kim loi.


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- Kim loi do nht l Au, sau n Ag, Al, Cu, Sn,

- Kim loi dn in, dn nhit tt nht l Ag, sau n Cu, Au, Al, Fe,

- Kim loi c khi lng ring D < 5 gam/cm3 l kim loi nh, nh : Na, Li, Mg, Al,

- Kim loi c khi lng ring D > 5 gam/cm3 l kim loi nng, nh : Cr, Fe, Zn, Pb, Ag, Hg,

- Kim loi nh nht l Li, kim loi nng nht l Os.

- Kim loi d nng chy nht l Hg (-39oC).- Kim loi kh nng chy nht l W (3410oC).

- Kim loi mm nht l Cs, kim loi cng nht l Cr.

I II. Tnh cht ho hc chung ca kim loiTrong mt chu k, nguyn t ca cc nguyn t kim loi c bn knh tng i ln hn v in

tch ht nhn nh hn so vi phi kim, s electron ho tr t, lc lin kt vi ht nhn ca nhngelectron ny tng i yu nn chng d tch khi nguyn t. V vy, tnh cht ho hc chung cakim loi l tnh kh.

M Mn+ + ne

1. Tc dng vi phi kimNhiu kim loi c th khc phi kim n s oxi ho m, ng thi nguyn t kim loi b oxi

ho n s oxi ho dng.

a. Tc dng vi cloHu ht cc kim loi u c th kh trc tip clo to ra mui clorua. V d : Dy st nng

chy mnh trong kh clo to ra khi mu nu l nhng ht cht rn st(III) clorua.oo o 3 1t

2 32Fe 3Cl 2 FeCl+

+

Trong phn ng ny Fe kh to

2Cl xung1

Cl

b. Tc dng vi oxiHu ht cc kim loi c th kh t

o

2O xung2

O

. V d : Khi t, bt nhm chy mnh trong

khng kh to ra nhm oxit.oo o 3 1t

2 2 34Al 3O 2Al O+

+

c. Tc dng vi lu hunh

Nhiu kim loi c th kh lu hunh to

S xung2

S

. Phn ng cn un nng (tr Hg). V d :oo o 2 2tFe S Fe S

+

+ +

+ o

o o 2 2t thngHg S Hg S

2. Tc dng vi dung dch axita. Vi dung dch HCl, H2SO4 long

Nhiu kim loi c th kh c ion H+

trong cc dung dch axit trn thnh hiro.V d :o 1 2 1 o

2 2Fe 2 H Cl FeCl H+ +

+ +

b. Vi dung dch HNO3, H2SO4c

Hu ht kim loi (tr Pt, Au) kh c

5

N

+

(trong HNO3) v

6

S

+

(trong H2SO4 ) xung s oxi hothp hn. V d :


14/88



+ + +

+ + +o

o 5 2 2t

3 3 2 23Cu 8H N O 3Cu(NO ) 2 N O 4H O

+ + +

+ + +o

o 5 2 2t

2 4 4 2 2Cu 2H SO Cu SO SO 2H O

Ch :HNO3, H2SO4 c, ngui lm thng ho Al, Fe, Cr, ...

3.Tc dng vi ncCc kim loi nhm IA v IIA ca bng tun hon (tr Be, Mg) do c tnh kh mnh nn cth kh c H2O nhit thng thnh hiro. Cc kim loi cn li c tnh kh yu hn nn chkh c H2O nhit cao (Fe, Zn,...) hoc khng kh c H2O (Ag, Au,...). V d:

o 1 1 o

2 2Na 2 H O 2Na OH H+ +

+ +

4. Tc dng vi dung dch muiKim loi mnh hn c th kh c ion ca kim loi yu hn trong dung dch mui thnh kim

loi t do. V d : Ngm mt inh st ( lm sch lp g) vo dung dch CuSO4, sau mt thi gianmu xanh ca dung dch CuSO4 b nht dn v trn inh st c lp ng mu bm vo.

o 2 2 o

4 4Fe CuSO FeSO Cu+ +

+ +

IV. Hp kim1. nh ngha

Hp kim l nhng vt liu kim loi c cha mt kim loi c bn v mt skim loi hoc phi kimkhc.

V d : Thp l hp kim ca st vi cacbon v mt s nguyn t khc.

2. Tnh cht ca hp kima. Tnh cht ha hc : Tng t nh cc cht trong hn hp ban u.b. Tnh cht vt l : So vi cc cht trong hn hp ban u th hp kim c :

- Tnh dn in, dn nhit km hn.

- Nhit nng chy thp hn.

- Cng hn, gin hn.


15/88



BI 2 : DY IN HO CA KIM LOI

A. L THUYTI. Cp oxi ho - khca kim loi

Nguyn t kim loi d nhng electron tr thnh ion kim loi, ngc li ion kim loi c thnhn electron trthnh nguyn t kim loi. V d :

+Ag +1e Ag

2+Cu +2e Cu

2+Fe +2e Fe

Cc nguyn t kim loi (Ag, Cu, Fe,...) ng vai tr cht kh, cc ion kim loi (Ag+, Cu2+, Fe2+

...) ng vai tr cht oxi ho.

Cht oxi ho v cht kh ca cng mt nguyn t kim loi to nn cp oxi ho - kh. V d ta

c cp oxi ho - kh : Ag+

/Ag ; Cu2+

/Cu ; Fe2+

/Fe.c im ca cp oxi ha - kh :Trong cp oxi ha - kh, dng khc tnh khcng mnh th

dng oxi ha c tnh oxi ha cng yu v ngc li.I I. Pin in ha1. Cu to v hot ng

- Kim loi mnh lm in cc m (anot) v bn mn.

- Kim loi c tnh kh yu hn c bo v.

- Cu mui c tc dng trung ha dung dch

2. Tnh sut in ng ca pin in ha

Epin = Ecatot - Eanot = Emax - Emin xc nh tnh kh cc kim loi v tnh oxi ha cc ion kim loi, ngi ta thit lp cc pin

in ha vi mt in cc bng H2 lm chun cn in cc cn li l kim loi cn xc nh. Qua ngi ta a ra c mt gi tr gi l th in cc chun. K hiu n

o

MM

E + .

IV. Dy in ho ca kim loi1. Dyin ha :

Dyin ha ca kim loi l mt dy cc cp oxi ha - khc sp xp theo chiu tng dntnh oxi ha ca ion kim loi v gim dn tnh khca nguyn tkimloi.

Ngi ta so snh tnh cht ca nhiu cp oxi ho - kh v sp xp thnh dy in ho ca

kim loi :Mg2+ Al3+ Zn2+ Fe2+ Ni2+ Sn2+ Pb2+ H+ Cu2+ Fe3+ Ag

+Au3+

Mg Al Zn Fe Ni Sn Pb H2 Cu Fe2+ Ag Au

n

o

MM

E + -2,37 -,166 -0,76 -0,44 -0,23 -0,14 -0,13 0,00 0,34 0,77 0,8 1,5

Chiu gim dn tnh khca kim loi v tng dn tnh oxi ha ca ion kim loi2. ngha ca dyin ho ca kim loia. Don chiu xy ra phnng oxi ha - kh

Dy in ho ca kim loi cho php d on chiu ca phn ng gia 2 cp oxi ho - kh theo

quy tc (anpha) : Phn ng gia 2 cp oxi ho - kh s xy ra theo chiu, cht oxi ho mnh nhtsoxi ho cht khmnh nht, sinh ra cht oxi ho yu hn v cht khyu hn.


16/88



V d : Phn ng gia 2 cp Ag+/Ag v Cu2+/Cu xy ra theo chiu ion Ag+ oxi ho Cu to ra ionCu2+ v Ag.

2Ag+ + Cu Cu2+ + 2AgCht oxi ho mnh Cht kh mnh Cht oxi ho yu Cht kh yu

b. So snh tnh cht ca cc cp oxi ho - khV d : So snh tnh cht ca hai cp oxi ho - kh Cu2+/Cu v Ag+ /Ag, thc nghim cho thy

Cu tc dng c vi dung dch mui Ag+ theo phng trnh ion rt gn :

Cu + 2Ag+ Cu2+ + 2Ag

(kh mnh) (oxi ha mnh) (kh yu) (oxi ha yu)

Theo phng trnh ta thy : Tnh kh : Cu > Ag; Tnh oxi ha : Ag+ > Cu2+

Ai quyt nh sphn mnhLeonardo da Vinci v bc Ba tic ly mt by nm lin. l bc tranh v Cha Jsu v 12 v tng trong ba n cui cng trc khi ngi b mn Judas phn bi.Leonardo tm ngi mu rt cng phu. Gia hng ngn thanh nin ng mi chn oc mt chngtrai c gng mt thnh thin, mt tnh cch thanh khit tuyt i lm mu v Cha Jsu. Da Vincilm vic khng mt mi sut su thng lin trc chng trai, v hnh nh Cha Jsu hin ra trn

bn v.Su nm tip theo ng ln lt v xong 12 v tng , ch cn c Judas, v mn phn biCha v 30 ng bc. Ha smun tm mt ngi n ng c khun mt hn ln s hm li, la lc,o c gi v cc k tn c. Khun mt phi tot ln tnh cch ca k sn sng bn i ngi bn

thn nht, ngi thy knh yu nht ca chnh mnh ...Cuc tm kim dng nh v vng. Bao nhiu gng mt xu xa nht, c c nht, Vinci u thycha biu l ci c ca Judas. Mt hm Vinci c thng bo c mt k m ngoi hnh c thp ng c yu cu ca ng. Hn ang trong mt hm ngc Roma, b kt n t hnh v tigit ngi v nhiu ti c ty tri khc ...Vinci lp tc ln ng n Roma. Trc mt ng l mt g n ng nc da en sm vi mi tcdi bn thu xa xung gng mt, mt gng mt xu xa, him c, hin hin r tnh cch ca mtk hon ton b tha ha. ng y l Judas!c s cho php c bit ca c vua, ngi t c a ti Milan ni bc tranh ang v d. Mingy tn t ngi trc Da Vinci v ngi ha sthin ti cn mn vi cng vic truyn ti vo bctranh din mo ca mt k phn phc.

Khi nt v cui cng c hon tt, kit sc v phi i mt vi ci c mt thi gian di, Vinciquay sang bo lnh gc:" Cc ngi em hn i i!". Lnh canh tm ly k t t, nhng hn tnhin vng ra v lao n qu xung bn Da Vinci, khc nc ln :" i, ngi Da Vinci! Hy nhn con!

Ngi khng nhn ra con ?".Da Vinci quan st k m su thng qua ng lin tc nhn mt. Cui cng ng p: " Khng! Tacha tng nhn thy ngi cho n khi ngi c a n t hm ngc Roma ...". Tn t t kuln: " Ngi Vinci ... Hy nhn k ti! Ti chnh l ngi m by nm v trc ngi chn lm muv Cha Jsu..."Cu chuyn ny l c tht, nh bc tranh Ba tic ly l c tht. Chng trai tng c chn lm hnhmu ca Cha Jsu, ch sau hn 2000 ngy t bin mnh thnh hnh tng hon ho ca k phn

bi gh gm nht trong lch s.

Tng lai khng hc nh trc. Chnh chng ta l ngi quyt nh s phn ca chnhmnh...


17/88



B. PHNG PHP GII BI TP V KIM LOII. Phng php

- Phn ng ca kim loi vi phi kim; vi cc dung dch : axit, kim, mui l phn ng oxi ha -kh, nn phng php c trng gii bi tp v kim loi l phng php bo ton electron,ngoi ra c th s dng phng php tng gim khi lng i vi nhng bi tp lin quan n

kim loi tc dng vi dung dch mui. i vi nhng bi tp tng hp lin quan n nhiu loiphn ng th c th kt hp cc phng php : bo ton electron, bo ton khi lng, tng gimkhi lng, bo ton nguyn t...

I I. n tp vphng php bo ton electron1. Ni dung nh lut bo ton electron :

- Trong phnng oxi ha - kh, tng s electron m cc cht khnhng lun bng tng selectron m cc cht oxi ha nhn.2. Nguyn tc p dng :

- Trong phnng oxi ha - kh, tng smol electron m cc cht khnhng lun bng tngsmol electron m cc cht oxi ha nhn.

Lu : Khi gii bi tp bng phng php bo ton electron ta cn phi xc nh y ,chnh xc cht khv cht oxi ha; trng thi s oxi ha ca cht kh, cht oxi ha trc vsau phn ng; khng cn quan tm n s oxi ha ca cht khv cht oxi ha cc qu trnhtrung gian.

3. Cc dng bi tpa. Kim loi tc dng vi phi kimV d1: Hn hp X gm S v Br2 tc dng va vi hn hp Y gm 9,75 gam Zn, 6,4 gam Cu v9,0 gam Ca thu c 53,15 gam cht rn. Khi lng ca S trong X c gi tr l :

A. 16 gam. B. 32 gam. C. 40 gam. D. 12 gam.

Hng dn giiGi s mol S l x v s mol Br2 l y ta c :

32x + 160y = 53,15 9,75 6,4 9,0 32x + 160y = 28 (1)

p dng nh lut bo ton electron ta c :

nelectron cho = nelectron nhn 2S Br Zn Cu Ca

2.n 2.n 2.n 2.n 2.n+ = + + (*)

2x + 2y = 0,15.2 + 0,1.2 + 0,225.2 2x + 2y = 0,95 (2)

T (1) v (2) ta c : x = 0,375 v y = 0,1 mS = 0,375.32 = 12 gam.

Nu nu cc em hc sinh khng hnh dung c biu thc (*) th c thvit cc qu trnh oxiha - kh, ri p dngnh lut bo ton electronsuy ra (*):

Qu trnh oxi ha : Qu trnh kh :Zn Zn+2 + 2e S + 2e S-2

mol : 0,15 0,3 mol: x 2x

Cu Cu+2 + 2e Br2 + 2e 2Br-

mol : 0,1 0,2 mol: y 2y

Ca Ca+2 + 2e

mol : 0,225 0,45

p n D.


18/88



V d 2: Cho 11,2 lt hn hp kh A gm clo v oxi phn ng va ht vi 16,98 gam hn hp Bgm magie v nhm to ra 42,34 gam hn hp cc mui clorua v oxit hai kim loi. Thnh phn %khi lng ca magie v nhm trong hn hp B l :

A. 48% v 52%. B. 77,74% v 22,26%.C. 43,15% v 56,85%. D. 75% v 25%.

Hng dn giiTheo gi thit ta c :

2 2(Cl ,O )n 0,5= mol ; 2 2(Cl ,O )m 25,36= gam.

Gi x v y ln lt l s mol ca Cl2 v O2 ta c :

x+y 0,5 x 0,24

71x+32y 25,36 y 0,26

= =

= =

Gi a v b ln lt l s mol ca Al v Mg tac :

27a + 24b = 16,98 (1)


nelectron cho = nelectron nhn 2 2Al Mg Cl O3.n 2.n 2.n 4.n+ = + 3a + 2b = 1,52 (2)T (1) v (2) suy ra : a = 0,14 ; b = 0,55

Thnh phn % khi lng ca magie v nhm trong hn hp B l :

% Al =0,14.27

.100% 22,26%16,98

= ; % Mg = (100 22,26)% = 77,74%.

p n B.b. Kim loi tc dng vi dung dch axitV d 1:Ho tan ht 9,6 gam kim loi M trong dung dch H2SO4 c, nng, thu c SO2 l sn

phm kh duy nht. Cho ton b lng SO2 ny hp th vo 0,5 lt dung dch NaOH 0,6M, sauphn ng em c cn dung dch c 18,9 gam cht rn. Kim loi M l :

A. Ca. B. Mg. C. Fe. D. Cu.

Hng dn giiKh SO2 tc dng vi dung dch NaOH c th xy ra cc kh nng :

- To ra mui NaHSO3.

- To ra mui Na2SO3.

- To ra mui NaHSO3 v Na2SO3.

- To ra mui Na2SO3 v d NaOH.

Gi s phn ng to ra hai mui NaHSO3 (x mol) v Na2SO3 (y mol).

Phng trnh phn ng :

NaOH + SO2 NaHSO3 (1)

mol : x x x

2NaOH + SO2 Na2SO3 (2)

mol : 2y y y

Theo (1), (2) v gi thit ta c :

x+2y 0,3 x 0

104x+126y 18,9 y 0,15

= =

= =

Nh vy phn ng ch to ra mui Na2SO3.


19/88



Gi n l ha tr ca kim loi M. p dng nh lut bo ton electron ta c :

2M SO

9,6n.n 2.n .n 2.0,15 M 32n

M= = =

n 2

M 64

=

=

Vy kim loi M l Cu.

p n D.V d 2:Cho 1,35 gam hn hp gm Cu, Mg, Al tc dng vi dung dch HNO3 d, thu c 1,12lt (ktc) hn hp kh NO v NO2 c t khi so vi hiro bng 20. Tng khi lng mui nitrat sinhra l :

A. 66,75 gam. B. 33,35 gam. C. 6,775 gam. D. 3,335 gam.

Hng dn giip dng s ng cho cho hn hp N2O v NO ta c :

2NOn 46 40 30 = 10

40

NOn 30 46 40 = 6

Suy ra :2NO NO

5n .0, 05 0,03125 mol , n 0, 05 0,03125 0,01875 mol.

8= = = =

Ta c cc qu trnh oxi ha kh :

Qu trnh kh :

NO3 + 3e NO

mol : 0,05625 0,01875

NO3 + 1e NO2

mol : 0,03125 0,03125Nh vy, tng s mol electron nhn = tng s mol electron nhng = 0,0875 mol.

Thay cc kim loi Cu, Mg, Al bng kim loi M.

Qu trnh oxi ha :n

3 nM M (NO ) ne

+

+

mol :0,0875

n 0,0875

Khi lng mui nitrat sinh ra l :

m = 3 nM (NO )m = 3M NOm +m = 1,35 + 0,0875n.n.62 = 6,775 gam.

Suy ra :3

electron t rao oiN O tao muoin n =

p n C.

V d3: Cho 12,9 gam hn hp Al, Mg phn ng va ht vi dung dch H2SO4 c, nng. Sau phnng thu c 0,125 mol S, 0,2 mol SO2 v dung dch X. C cn dung dch X thu c m gam mui.Gi tr ca m l :

A. 68,1. B. 84,2. C. 64,2. D. 123,3.

Hng dn giit s mol ca Al v Mg ln lt l x v y.

Phng trnh theo tng khi lng ca Al v Mg : 27x + 24y = 12,9 (1)

2NO

NO

n 10 5

n 6 3 = =


20/88




nelectron cho = nelectron nhn 3x + 2y = 0,125.6 + 0,2.2 = 1,15 (2)

T (1) v (2) ta c : x = 0,1 v y = 0,425

Phn ng to ra mui sunfat Al2(SO4)3 (0,05 mol) v MgSO4 (0,425 mol) nn khi lng muithu c l :

m = 0,05. 342 + 0,425.120 = 68,1 gam.p n A.c. Kim loi tc dng vi dung dch muiTnh ton theo phng trnh phnng

V d 1: Cho m gam Mg vo dung dch cha 0,12 mol FeCl3. Sau khi phn ng xy ra hon tonthu c 3,36 gam cht rn. Gi tr ca m l :

A. 2,88. B. 2,16. C. 4,32. D. 5,04.

Hng dn giiKhi cho Mg vo dung dch mui Fe3+, u tin Mg kh Fe3+ thnh Fe2+, sau Mg kh Fe2+ v

Fe. Vy phn ng (1) xy ra xong sau mi n phn ng (2).Gi s tt c lng Fe2+ chuyn ht thnh Fe th khi lng st to thnh l 6,72 gam. Trn thc

t khi lng cht rn thu c ch l 3,36 gam, suy ra Fe2+ cha phn ng ht, Mg phn nght, 3,36 gam cht rn l Fe to thnh.

Phng trnh phn ng :

Mg + 2Fe3+ Mg2+ + 2Fe2+ (1)

mol: 0,06 0,12 0,06 0,12

Mg + Fe2+ Mg2+ + Fe (2)

mol: 0,06 0,06 0,06 0,06

Cn c vo (1) v (2) suy ra : M g M gn 0,12 mol m 0,12.24 2,88 gam.= = =

p n A.

V d2: Cho 100 ml dung dch FeCl2 1,2M tc dng vi 200 ml dung dch AgNO3 2M, thu c mgam kt ta. Gi tr ca m l :

A. 12,96. B. 34,44. C. 47,4. D. 30,18.

Hng dn giiTheo gi thit ta c :

22

3

FeCl Fe Cl

AgNO Ag

n 0,1.1,2 0,12 mol n 0,12 mol, n 0, 24 mol.

n 0, 2.2 0,4 mol n 0, 4 mol.

+

+

= = = =

= = =

Phng trnh phn ng :

Ag+ + Cl- AgCl (1)

mol: 0,24 0,24 0,24

Ag+ + Fe2+ Ag + Fe3+ (2)

mol: 0,12 0,12 0,12

Theo phng trnh phn ng ta thy kt ta thu c l Ag v AgCl.

(Ag AgCl)m m 0, 24.143,5 0,12.108 47,4 gam.= = + =

p n C.


21/88



Lu :Trong dung dch, thtxy ra phnng l :+ Phnng traoi.+ Phnng oxi ha - kh.

bi trn nu (1) Ag+ ht th phnng (2) khng xy ra.Sphng php tng gimkhi lng

V d 3: Ngm mt thanh ng c khi lng 15 gam trong 340 gam dung dch AgNO3 6%. Saumt thi gian ly vt ra thy khi lng AgNO3 trong dung dch gim 25%. Khi lng ca vt sau

phn ng l :


Hng dn gii

3AgNO ( )

340.6n =

170.100b= 0,12 mol.

3AgNO ( )

25n = 0,12.

100p-= 0,03 mol.

Phng trnh phn ng :

Cu + 2AgNO3 Cu(NO3)2 + 2Ag

mol : 0,015 0,03 0,03

mvt sau phn ng = mthanh ng ban u + mAg (sinh ra) mCu (phn ng)

= 15 + 108.0,03 64.0,015 = 17,28 gam.

p n C.

V d 4: Nhng thanh km vo dung dch cha 8,32 gam CdSO4. Sau khi kh hon ton ion Cd2+khi lng thanh km tng 2,35% so vi ban u. Khi lng thanh km ban u l :

A. 60 gam. B. 70 gam. C. 80 gam. D. 90 gam.Hng dn gii

Gi khi lng thanh km ban u l a gam th khi lng tng thm l2,35a

100gam.

Phng trnh phn ng :

Zn + CdSO4 ZnSO4 + Cd (1)

mol : 0,04 0,04 0,04

Theo gi thit v (1) ta c : 0,04.112 0,04.65 =2,35a

100 a = 80 gam.

p n C.V d 5:Cho m gam bt Zn vo 500 ml dung dch Fe2(SO4)3 0,24M. Sau khi cc phn ng xy rahon ton, khi lng dung dch tng thm 9,6 gam so vi khi lng dung dch ban u. Gi trca m l :

A.32,50. B. 20,80. C. 29,25. D. 48,75.

Hng dn giiPhng trnh phn ng :

2Fe3+ + Zn 2Fe2+ + Zn2+

mol: 0,24 0,12 0,24 0,12

Fe2+ + Zn Fe + Zn2+mol: x x x x


22/88



V trc v sau phn ng tng khi lng khng i nn sau phn ng khi lng dung dchtng 9,6 gam th khi lng kim loi gim 9,6 gam.

Theo phng trnh ta thy :

Khi lng kim loi gim = mZnphn ng - mFesinh ra = (0,12+x)65 56x = 9,6 x= 0,2

Vy mZn = (0,2 + 0,12).65 = 20,8 gam.

p n B.V d6: Nhng mt thanh km v mt thanh st vo cng mt dung dch CuSO4. Sau mt thi gianly hai thanh kim loi ra thy trong dung dch cn li c nng mol ZnSO4 bng 2,5 ln nng mol FeSO4. Mt khc, khi lng dung dch gim 2,2 gam. Khi lng ng bm ln thanh km v

bm ln thanh st ln lt l :

A. 12,8 gam; 32 gam. B. 64 gam; 25,6 gam.C. 32 gam; 12,8 gam. D. 25,6 gam; 64 gam.

Hng dn giiV trong cng dung dch sau phn ng [ZnSO4] = 2,5[FeSO4] nn suy ra

4 4ZnSO FeSOn 2,5n .=

t4 4FeSO ZnSO

n x mol ; n 2,5x mol= = .

Phng trnh phn ng ha hc :

Zn + CuSO4 ZnSO4 + Cu (1)

mol : 2,5x 2,5x 2,5x 2,5x

Fe + CuSO4 FeSO4 + Cu (2)

mol : x x x x

Ta nhn thy gim khi lng ca dung dch bng tng khi lng ca kim loi. Do :

mCu (sinh ra) mZn (phn ng) mFe (phn ng) = 2,2

64.(2,5x + x) 65.2,5x 56x = 2,2

x = 0,4 mol.

Vy : mCu (bm ln thanh km) = 64.2,5.0,4 = 64 gam ; mCu (bm ln thanh st) = 64.0,4 = 25,6 gam.

p n B.

V d 7: Cho 2,7 gam hn hp bt X gm Fe v Zn tc dng vi dung dch CuSO4. Sau mt thigian, thu c dung dch Y v 2,84 gam cht rn Z. Cho ton b Z vo dung dch H2SO4 (long,d). Sau khi cc phn ng kt thc th khi lng cht rn gim 0,28 gam v dung dch thu cch cha mt mui duy nht. Phn trm khi lng ca Fe trong X l :

A. 58,52%. B. 51,85%. C. 48,15%. D. 41,48%.

Hng dn giiPhn ng ca hn hp X vi dung dch CuSO4 lm khi lng cht rn tng chng t Fe

tham gia phn ng (v nu ch c Zn phn ng th khi lng cht rn phi gim do nguyn t khica Zn ln hn Cu). Cht rn Z phn ng vi H2SO4 th thy khi lng cht rn gim v dung dchthu c ch c mt mui duy nht nn kim loi d ch c Fe, khi lng Fe d l 0,28 gam.

Gi s mol ca Zn v Fe phn ng vi dung dch mui CuSO4 ln lt l x v y mol.

Phng trnh phn ng :

Zn + Cu2+ Zn2+ + Cu (1)

mol: x x x

Fe + Cu2+

Fe2+

+ Cu (2)mol: y y y


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Theo cc phn ng v gi thit ta c :

+ = =

+ + = =

65x 56y 2,7 0,28 x 0,02

2,7 65x 56y 64x 64y 2,84 y 0,02

Phn trm khi lng ca Fe trong X l :+

=0,02.56 0,28

.100 51,85%

2,7

.

p n B.

V d 8: Cho 3,78 gam bt Al phn ng va vi dung dch mui XCl3 to thnh dung dch Y.Khi lng cht tan trong dung dch Y gim 4,06 gam so vi dung dch XCl3. Cng thc ca muiXCl3 l :

A. FeCl3. B. AlCl3. C. CrCl3. D. Khng xc nh.

Hng dn gii

Al

3,18n 0,14 mol

27= = .

Phng trnh phn ng :Al + XCl3 AlCl3 + X (1)

mol : 0,14 0,14 0,14

Theo (1) v gi thit ta c : (X + 35,5.3).0,14 133,5.0,14 = 4,06 X = 56.

Vy kim loi X l Fe v mui FeCl3.

p n A.

V d 9: Nhng mt thanh graphit c ph mt lp kim loi ha tr (II) vo dung dch CuSO4 d.Sau phn ng khi lng ca thanh graphit gim i 0,24 gam. Cng thanh graphit ny nu cnhng vo dung dch AgNO3 d th khi phn ng xong thy khi lng thanh graphit tng ln 0,52

gam. Kim loi ha tr (II) l kim loi no sau y ?A. Pb. B. Cd. C. Al. D. Sn.

Hng dn giit kim loi ha tr (II) l M vi s mol l x mol.

Phng trnh phn ng ha hc :

M + CuSO4 MSO4 + Cu (1)

mol : x x x x

Theo (1) v gi thit ta c : Mx 64x = 0,24 (*)

M + 2AgNO3 M(NO3)2 + 2Ag (2)

mol : x 2x x 2xTheo (2) v gi thit ta c : 108.2x Mx = 0,52 (**)

Ly (*) chia cho (**) ta c phng trnh mt n M, t suy ra M = 112 (Cd).

p n B.


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V d 10: Nhng thanh kim loi M ho tr 2 vo dung dch CuSO4, sau mt thi gian ly thanh kimloi ra thy khi lng gim 0,05%. Mt khc nhng thanh kim loi trn vo dung dch Pb(NO3)2,sau mt thi gian thy khi lng tng 7,1%. Xc nh M, bit rng s mol CuSO4 v Pb(NO3)2tham gia 2 trng hp nh nhau.

A. Al. B. Zn. C. Mg. D. Fe.

Hng dn giiGi m l khi lng thanh kim loi, M l nguyn t khi ca kim loi, x l s mol mui phn

ng.Phng trnh phn ng ha hc :

M + CuSO4 MSO4 + Cu (1)

mol : x x x

Theo (1) v gi thit ta c : Mx 64x =0,05.m

100(*)

M + Pb(NO3)2 M(NO3)2 + Pb (2)

mol : x x x

Theo (2) v gi thit ta c : 207x Mx =7,1.m

100(**)

Ly (*) chia cho (**) ta c phng trnh mt n M, t suy ra M = 65 (Zn).

p n B.Sdng phng php bo ton electron

V d 11:Cho a mol kim loi Mg vo dung dch hn hp cha b mol CuSO4 v c mol FeSO4. Ktthc phn ng dung dch thu c cha 2 mui. Xc nh iu kin ph hp cho kt qu trn.

A. a b. B.b a < b +c. C.b a b +c. D. b < a < 0,5(b + c).

Hng dn giiTnh oxi ha : Cu2+ > Fe2+.

Th t phn ng :

Mg + Cu2+ Mg2+ + Cu (1)

Mg + Fe2+ Mg2+ + Fe (2)

Theo gi thit, sau phn ng thu c dung dch cha 2 mui, suy ra hai mui l Mg2+ v Fe2+.

V trong dung dch c mui Fe2+ nn s mol electron m Mg nhng nh hn s mol electronm Cu2+ v Fe2+ nhn, suy ra : 2 2Mg Cu Fe2n 2n 2.n a b c+ +< + < + (*).

Dung dch sau phn ng cha Mg

2+

v Fe

2+

nn (1) xy ra hon ton, (2) c th xy ra hoccha xy ra, nn s mol electron m Mg nhng ln hn hoc bng s mol electron m Cu2+ nhn,suy ra : 2Mg Cu2n 2n a b+ (**)

Vy b a < b +c.

p n B.

V d12:Cho hn hp gm 1,2 mol Mg v x mol Zn vo dung dch cha 2 mol Cu2+ v 1 mol Ag+n khi cc phn ng xy ra hon ton, thu c mt dung dch cha ba loi ion kim loi. Trongcc gi tr sau y, gi tr no ca x tho mn trng hp trn ?

A. 2. B. 1,2. C. 1,5. D. 1,8.

Hng dn giiTh t kh : Mg > Zn ; th t oxi ha : Ag+ > Cu2+.

Cn c vo th t kh ca cc kim loi v th t oxi ha ca cc ion suy ra dung dch sau phn


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ng cha cc ion l Mg2+, Zn2+ v Cu2+. Vy chng t Mg, Zn phn ng ht, Cu2+ d.

V mui Cu2+ d nn :electron cho electron nhan

n n 2.1,2 2x 2.2 1.1 x 1,3.< + < + <

Vy ch c phng n x = 1,2 l ph hp.

p n B.

V d13:Cho 2,8 gam bt st vo 200 ml dung dch gm AgNO3 0,1M v Cu(NO3)2 0,5M; khi ccphn ng xy ra hon ton thu c m gam cht rn X. Gi tr ca m l :A. 4,72. B. 4,08. C. 4,48. D. 3,20.

Hng dn giiS mol electron do Fe nhng Fe2n 0,1 mol.= =

S mol electron do Ag+ v Cu2+ nhn 2Ag Cun 2n+ += + = 0,02 + 0,1 = 0,12 mol.

Nh vy 2FeAg Ag Cun 2n n 2n+ + +< < + . Do Ag+, Fe phn ng ht, Cu2+ d.

2 2 CuCu d Cu p

0,12 0,1n 0,01 mol n n 0,04 mol.

2+ +

= = = =

Khi lng cht rn = Ag Cum m+ = 0,02.108 + 0,04.64 = 4,72 gam.p n A.

V d 14: Cho 0,42 gam hn hp bt Fe v Al vo 250 ml dung dch AgNO3 0,12M. Sau khi ccphn ng xy ra hon ton, thu c dung dch X v 3,333 gam cht rn. Khi lng Fe trong hnhp ban u l :


Hng dn giiGi s AgNO3 phn ng ht th mAg = 108.0,12.0,25 = 3,24 gam < 3,333 gam : ng!. Vy

AgNO3 ht, trong cht rn ngoi Ag cn c Fe d hoc Al d v Fe cha phn ng vi khi lng

l 3,333 3,24 = 0,093 gam.Khi lng Al v Fe phn ng vi dung dch AgNO3 l 0,42 - 0,093 = 0,327 gam.

Gi s mol ca Al v Fe phn ng ln lt l x v y (x > 0, y 0).

Phng trnh theo khi lng ca Al, Fe : 27x + 56y = 0,327 (1)

p dng nh lut bo ton electron ta c : 3x + 2y = 0,12.0,25 (2)

T suy ra x = 0,009 mol v y = 0,0015 mol.

St phn ng chng t Al ht, 0,093 gam kim loi d l Fe.

Khi lng ca Fe trong hn hp = 0,093 + 0,0015.56 = 0,177 gam.

p n C.

d. Kim loi tc dng vi dung dch kimV d1: Hn hp X gm Na v Al. Cho m gam X vo mt lng d nc th thot ra V lt kh. Nucng cho m gam X vo dung dch NaOH d th c 1,75V lt kh. Thnh phn phn trm theo khilng ca Na trong X l (bit cc th tch kh o trong cng iu kin) :

A. 41,94%. B. 77,31%. C. 49,87%. D. 29,87%.

Hng dn giiX tc dng vi dung dch NaOH d thu c lng kh nhiu hn so vi khi X tc dng vi

H2O, chng t khi X tc dng vi H2O th Al cn d, dung dch sau phn ng cha NaAlO2.

i vi cc cht kh th t l th tch cng chnh l t l mol nn cn c vo gi thit ta chn s

mol H2 gii phng hai trng hp ln lt l 1 mol v 1,75 mol.t s mol ca Na v Al tham gia phn ng vi H2O l x mol.


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2Na Al H1.n 3.n 2.n+ = 1.x + 3.x = 2.1 x = 0,5

t s mol Al ban u l y, khi X tc dng vi dung dch NaOH d th Al phn ng ht.


2Na Al H1.n 3.n 2.n+ =

1.0,5 + 3.y = 2.1,75 y = 1

Thnh phn phn trm theo khi lng ca Na trong X l :0,5.23

.100% 29,87%0,5.23 1.27

=+

.

p n D.e. Kim loi tc dng vi nhiu cht oxi ha (phi kim, dung dch axit, baz, mui)V d 1: Trn 56 gam bt Fe vi 16 gam bt lu hunh ri un nng (khng c khng kh) thuc cht rn A. Ho tan A bng dung dch axit HCl d c dung dch B v kh D. t chy Dcn V lt O2 (ktc). Bit cc phn ng xy ra hon ton. V c gi tr l :

A. 11,2 lt. B. 33,6 lt. C. 22,4 lt. D. 44,8 lt.

Hng dn gii

S phn ng :1 o

o o2

1 22 22t HCl O ,t

2 4 22

2

HFe: 1mol FeS: 0,5 mol H OFeCl

S: 0,5 mol Fe: 0,5 mol H SS O

+

+ +

+

+

Kh D l hn hp H2S v H2. t D thu c SO2 v H2O. Kt qu cui cng ca qu trnh phnng l Fe v S nhng electron, cn O2 thu electron.


nelectron cho = nelectron nhn 2 2 2Fe S O O O

2.n 4.n 4.n (* ) n 1 mol V 22,4 l t.+ = = =

Nu nu cc em hc sinh khng hnh dung c biu thc (*) th c thvit cc qu trnh oxiha - kh, ri p dngnh lut bo ton electrontnh smol ca O2:Qu trnh oxi ha : Qu trnh kh :

Fe Fe+2 + 2e O2 + 4e 2O-2

mol : 1 2 mol : x 4x

S S+4 + 4e

mol : 0,5 2

p n C.

V d 2: Cho m gam Al tc dng vi O2, thu c 25,8 gam cht rn X. Ho tan hon ton X bng

dung dch H2SO4 c nng, thu c 6,72 lt kh SO2 (ktc). Gi tr ca m l :A. 21,6. B. 16,2. C. 18,9. D. 13,5.

Hng dn gii

S phn ng :6

oo2 4

o 23 4

t , H S Ot 32 2 4 3 2 2o

2

Al Al O Al (SO ) + S O + H OAlO

+

+ +

Cn c vo s phn ng ta thy : Cht kh l Al ; cht oxi ha l O2 v H2SO4.

t s mol ca Al l x v s mol ca O2 l y (x, y > 0)

Phng trnh theo tng khi lng ca hn hp X : 27x + 32y = 25,8 (1)

p dng nh lut bo ton electron ta c : nelectron cho = nelectron nhn 3x = 4y + 0,3.2 (2)T (1), (2) suy ra x = 0,6 v y = 0,3.


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Vy khi lng nhm l : m = 0,6.27 = 16,2 gam.

Nu nu cc em hc sinh khng hnh dung c biu thc (2) th c thvit cc qu trnh oxiha - kh, ri p dngnh lut bo ton electronsuy ra (2):

Qu trnh oxi ha : Qu trnh kh :

Al Al+3 + 3e O2 + 4e 2O-2

mol : x 3x mol : y 4yS+6 + 2e S+4 (SO2)

mol : 0,6 0,3

p n B.

V d 3: a gam bt st ngoi khng kh, sau mt thi gian s chuyn thnh hn hp A c khilng l 75,2 gam gm Fe, FeO, Fe2O3 v Fe3O4. Cho hn hp A phn ng ht vi dung dchH2SO4 m c, nng thu c 6,72 lt kh SO2 (ktc). Khi lng a gam l :

A. 56 gam. B. 11,2 gam. C. 22,4 gam. D. 25,3 gam.

Hng dn gii

S phn ng :

o 6

2 4

2o 3 432O H S O

2 4 3 2 22 2

43

Fe, Fe OFe (A) Fe (SO ) SO H O

Fe O , FeO

+

+ ++

+ +

t s mol ca Fe v O2 ln lt l x v y.

Theo gi thit v nh lut bo ton khi lng ta c :

Am = 56x + 32y = 75,2 (*)


ne cho = ne nhn 3x = 4y + 0,3.2 (**)

T (*) v (**)x 1

y 0,6

=

= a = 1.56 = 56 gam.

p n A.

V d4: Nung m gam bt Cu trong oxi thu c 24,8 gam hn hp cht rn X gm Cu, CuO, Cu2O.Ho tan hon ton X bng H2SO4 c, nng thu c 4,48 lt (ktc) kh SO2 duy nht. Gi tr m l :


Hng dn gii

S phn ng :o 6

2 4

o 2 2 4O H S O

2 4 2 2

2

Cu

Cu (X) Cu O CuSO SO H O

Cu O

+ + ++

+ +

Cn c vo s phn ng ta thy : Cht kh l Cu (x mol) ; cht oxi ha l O2 (y mol) vH2SO4.

Ta c phng trnh theo tng khi lng ca hn hp X : 64x + 32y = 24,8 (1)p dng nh lut bo ton electron ta c :

nelectron cho = nelectron nhn2 2Cu O SO

2.n 4.n 2.n= + 2x = 4y + 0,2.2 (2)

T (1) v (2) ta c : x = 0,35 v y = 0,075 m = 0,35.64 = 22,4 gam.p n D.


28/88


29/88



Qu trnh kh :

Ag+ + 1e Ag Cu2+ + 2e Cu 2H+ + 2e H2

mol : x x x y 2y y 0,1 0,05

Theo nh lut bo ton electron, ta c phng trnh :

x + 2y + 0,1 = 0,5 hay x + 2y = 0,4 (1)

Mt khc, cht rn B khng tan l Ag: x mol ; Cu: y mol 108x + 64y = 28 (2)

Gii h (1), (2) ta c x = 0,2 mol ; y = 0,1 mol.

[ ]30,2

AgNO0,1

= = 2M ; [ ]3 20,1

Cu(NO )0,1

= = 1M.

p n B.

V d7: Cho 1,82 gam hn hp bt X gm Cu v Ag (t l s mol tng ng 4 : 1) vo 30 ml dungdch gm H2SO4 0,5M v HNO3 2M, sau khi cc phn ng xy ra hon ton, thu c a mol kh

NO (sn phm kh duy nht ca N+5). Trn a mol NO trn vi 0,1 mol O2 thu c hn hp kh Y.Cho ton b Y tc dng vi H2O, thu c 150 ml dung dch c pH = z. Gi tr ca z l :

A. 1. B. 3. C. 2. D. 4.Hng dn gii

nCu = 0,02 mol; nAg = 0,005 mol. Suy ra tng s mol electron cho ti a = 0,02.2 + 0,005.1 =0,045 mol.

Hn + = 0,09 mol;

3NOn = 0,06 mol.

4H+ + NO3- + 3e NO + 2H2O

mol: 0,06 0,015 0,045 0,015

Nh vy H+ v NO3- d, cn Ag, Cu phn ng ht.

S chuyn ha NO thnh HNO3 :oo

22 22 4 2 5O , H OO2 3N O N O H N O

+ + +++

Nhn xt :2NO O

3.n 4.n< nn O2 d, do NO chuyn ht thnh HNO3.

Suy ra3HNO NO 3

0,015n n 0,015 mol [HNO ] 0,1M pH 1.

0,15= = = = =

p n A.

V d 8: Cho 0,87 gam hn hp gm Fe, Cu v Al vo bnh ng 300 ml dung dch H2SO4 0,1M.Sau khi cc phn ng xy ra hon ton, thu c 0,32 gam cht rn v c 448 ml kh (ktc) thot ra.Thm tip vo bnh 0,425 gam NaNO3, khi cc phn ng kt thc th th tch kh NO (ktc, sn

phm kh duy nht) to thnh v khi lng mui trong dung dch l :A. 0,224 lt v 3,750 gam. B. 0,112 lt v 3,750 gam.C. 0,112 lt v 3,865 gam. D. 0,224 lt v 3,865 gam.

Hng dn gii

22 4 4

H SO H SOn 0,03 mol n 0,06 mol, n 0,03 mol.+ = = =

+ += = =2H H p H d

n 0,02 mol n 0,04 mol n 0,02 mol.

nCu = 0,005 mol.

t nFe = x mol ; nAl = y mol, ta c :

+ = = + = =

56x 27y 0, 55 x 0,0052x 3y 0,02.2 y 0,01


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Khi cho tip 0,005 mol NO3- vo bnh th s xy ra phn ng oxi ha Cu trc sau mi n

Fe2+.

V t l mol H+ v NO3- l 4 : 1 ng bng t l phn ng v p dng nh lut bo ton eletron,

ta c : + ++ = =2 23

Cu Fe p NO Fe p2n n 3n n 0,005 mol ng bng s mol Fe2+ trong dung dch nn

NO3-, H

+, Cu, Fe2+u ht.

= = =3

NO NONOn n 0,005 mol V 0,112 l t.

Khi lng mui trong dung dch l :

+= + + = + + =24

muoi (A l , Fe, Cu) SO Nam m m m 0,87 0,03.96 0,005.23 3,865 gam.

p n C.

10 iu lng ph nht trong cuciTrong hnh trnh to dng mt cuc i c ngha, nu bn l coi thng mt trong 10 iu thityu di y, coi nh bn tnh mt mt phn nha sng ca chnh mnh.1. Sc khe : Lc cn tr, ngi ta thng li vo sc sng trn tr ang c. H lm vic nhin, vui chi thu m, n ung khng iu .... C nh th, c th mt mi v lo ho nhanh.Khi v gi, c nu ko sc kho th mun.2. Thi gian : Mi thi khc "vng ngc" qua i l khng bao gily li c. Vy m khng himk nm 8 gi lm vic qua ca s. Mi ngy, hy nhn li xem mnh lm c iu g. Nu cutr li l "khng"!, hy xem li qu thi gian ca bn nh!3. Tin bc : Nhiu ngi h c tin l mua sm, tiu xi hoang ph trong pht chc. n khi cnmt s tin nh, h cng phi i vay mn. Nhng ai khng bit tit kim tin bc, s khng bao

gishu c mt gia ti ln.

4. Tui tr : L qung thi gian m con ngi c nhiu sc kho v tr tu lm nhng iu lnlao. Vy m c ngi qun mt iu ny. "Tr n chi, gi hi hn" l li khuyn dnh chonhng ai ph hoi tui thanh xun cho nhng tr v b.5. Khng c sch : Sch truyn b vn minh. Khng c sch, lch s im lng, vn chng cmic, khoa hc t lit, t tng v suy xt ng. T sch, bn c th khm ph bit bao iu kth trn khp th gii. Tht ph "na cuc i" cho nhng ai cha bao gibit c sch l g!6. C hi : C hi l iu khng d dng n vi chng ta trong i. Mt c may c th bin bnthnh gim c thnh t hay mt t ph lm tin. Nu th vn may vt khi tm tay, bn khc th tin v pha trc.7. Nhan sc : L v kh li hi nht ca ph n. C nhan sc, bn s t tin v chim c nhiu u

th hn so vi ngi khc. Tuy nhin, "tui th" ca nhan sc c hn. Tht hoang ph khi sc pxung dc. Hy chm sc mnh ngay t by gi.8. Sng c thn : Ph n ngy nay theo tro lu "ch ngha c thn". Thc t l khi sng mtmnh, bn rt c n v d cm thy thiu vng vng tay yu thng ca chng con. Bn bu gianh chnh l mt nim vui. Sng c thn, bn lng ph tnh cm p y.9. Khng i du lch : Mt vnhn tng ni: "Khi i du lch v, con ngi ta ln thm v chcchn mt iu l tri t phi nh li". V th, nu cho rng i du lch ch lm hoang ph thi gianv tin bc, bn hy nghli nh!10. Khng hc tp : Mt ngi lun bit trau di kin thc s d thnh cng hn ngi ch bit tmn vi nhng g mnh bit. Nu khng hc hnh, bn ang lng ph b c y!


31/88



BI 3 : SIN PHN

A. TM TT L THUYTI. nh ngha

in phn l qu trnh oxi ho - khxy ra trn bmt cc in cc khi cho dng in mtchiu i qua dung dch cht in li hoc cht in li trng thi nng chy.

S in phn l qu trnh s dng in nng to ra s bin i ha hc.

V d: in phn NaCl nng chy iu ch Na.

2NaCl pnc 2Na + Cl2

in cc: L thanh kim loi hoc cc vt dn in khc nh cacbon (graphit), nh n ccelectron chuyn t dung dch trong bnh in phn vo mch in hoc ngc li, chuyn t mchin vo dung dch.

+ in cc ni vi cc m () ca ngun in c gi l catot - cc m.+ in cc ni vi cc dng (+) ca ngun in c gi l anot - cc dng.

in cc tr : L in cc ch ng vai tr cht dn in, khng tham gia cho nhn electron(oxi ho - kh) trong qu trnh in phn. l in cc platin (Pt), cacbon (graphit).

Trn b mt catot, cation ca cht in li n nhn electron.

(tng qut: Cht oxi ho n nhn electron).Xt v d trn: Na+ + 1e Na

Vy trn catot xy ra skh, c s chuyn electron tin cc n cation cht in li. Trn b mt anot, anion ca cht in li n nhng electron.

(tng qut: Cht khnhng electron).Cng xt v d trn : 2Cl Cl2 + 2e

Vy trn anot xy ra soxi ho, c s chuyn electron t anion ca cht in li ti b mt incc.

II . Sin phn cht in li1. in phn nng chy

in phn nng chy thng dng iu ch cc kim loi hot ng mnh nh kim loikim, kim th, nhm v mt s phi kim nh F2.

V d 1 : in phn Al2O3 nng chy iu ch Al.

Al2O3ot 2Al3+ + 3O2-

catot (cc m) : 4Al3+ + 12e 4Al (1)

anot (cc dng) : 6O2- 3O2 + 12e (2)

2Al2O3pnc 4Al + 3O2 (3)

(1), (2) l cc phn ng xy ra trn b mt cc in cc, (3) l phn ng in phn tng qut.

Khng thin phn nng chy AlCl3 v l hp cht cng ha tr, nhit cao n khngnng chy thnh ion m thng hoa.

V d 2 : in phn MgCl2 nng chy iu ch Mg.

MgCl2ot Mg2+ + 2Cl-

catot : Mg2+ + 2e Mg

anot : 2Cl- Cl2 + 2eMgCl2

pnc Mg + Cl2


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V d 3 :in phn nng chy NaOHNaOH Na+ + OH-

catot : 2Na+ + 2e 2Na

anot : 2OH- 1

2O2 + H2O + 2e

2NaOH pnc Na +1

2O2 + H2O

2. in phn dung dch cht in lia. Nguyn tc: Khi in phn dung dch nc, ngoi cc ion ca cht in li cn c th c cc ionH+ v ion OH ca nc v bn thn kim loi lm in cc tham gia cc qu trnh oxi ho - khin cc. Khi qu trnh oxi ho - kh thc t xy ra ph thuc vo tnh oxi ho - kh mnh hayyu ca cc cht trong bnh in phn. Ta xt trng hp in phn dung dch vi in cc tr.

Thtkh catot :Ni chung, nu kim loi c tnh kh cng yu th cation kim loi c tnh oxi ho cng mnh v

cng d b kh.+ Khi in phn dung dch nc, thng nhng kim loi no ng sau nhm s thot ra trn

catot: Mn+ + ne M

+ Nu trong dung dch cht in li ch c cation ca kim loi c tnh kh mnh (t K+ nAl3+), nhng cation ny l nhng cht oxi ho yu, chng kh b kh hn cc phn t nc. Khi ,catot xy ra s kh cc phn t nc thnh kh hiro v ion OH:

2H2O 2H+ + 2OH

2H+ + 2e H2

2H2O + 2e H2 + 2OH

- Th t kh ti catot (cc m) xy ra theo th t u tin tphi qua tri :Xt cc cation

Thtoxi hoanot:Ni chung, nhng phi kim c tnh oxi ho cng yu th anion ca n c tnh kh cng mnh v

cng d b oxi ho.Thng khi in phn dung dch nc, th t phng in (in phn) ca cc anion nh sau :

+ Nu trong dung dch cht in li c anion gc axit khng c oxi (S2, I, Br, Cl...).Nhng ion ny d b oxi ho hn so vi phn t nc. Thc t trn anot ch xy ra s oxi ho ccion ny thnh nguyn t (phn t) t do: S2 S + 2e

2X X2 + 2e

+ Nu trong dung dch cht in li ch c anion gc axit c oxi (SO42, NO3

, ClO4...),

nhng anion ny kh b oxi ho hn cc phn t nc. Do vy trn anot ch xy ra s oxi ho ccphn t nc to ra kh oxi v ion H+: 4H2O 4H

+ + 4OH

4OH

O2 + 2H2O + 4e2H2O O2 + 4H

+ + 4e

K+ Na+ Mg + Al + Zn + Fe + Ni + H+ Cu + Fe + Ag+ ...

Cc ion khng b in phntrong dung dch

Cc ion b in phn trong dung dch

H2O


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- Th t oxi ha ti anot (cc dng) xy ra theo th t u tin ttri qua phi :Xt cc anion

- Cc ion tiu biu: Cation Na+ Cu2+ H+

Anion OH Cl SO42

- Cc cht tiu biu : CuCl2 , CuSO4 , NaCl , NaOH , H2SO4 , Na2SO4.

b. Cc trng hp c th: in phn dung dch mui ca axit khng c oxi (HCl, HBr...) vi cc kim loi t sau nhm.V d: + in phn dung dch CuCl2.

CuCl2 Cu2+ + 2Cl

H2O H+ + OH

Ti catot (): 1 Cu2+ + 2e Cu

Ti anot (+): 1 2Cl Cl2 + 2e

Phng trnh ion: Cu2+ + 2Cl pdd Cu + Cl2

(catot) (anot)

Phng trnh phn t : CuCl2pdd Cu + Cl2

in phn dung dch mui ca axit c oxi (H2SO4, HNO3...) vi cc kim loi t sau nhm.

V d: in phn dung dch CuSO4 , in cc tr.

CuSO4 Cu2+ + SO4

2

H2O H+ + OH

Ti catot (): 2 Cu2+ + 2e Cu

Ti anot (+): 1 2H2O O2 + 4H+ + 4e

Phng trnh ion : 2Cu2+ + 2H2Opdd 2Cu + O2 + 4H

+

(catot) (anot)

Phng trnh phn t: 2CuSO4 + 2H2Opdd 2Cu + O2 + 2H2SO4

in phn dung dch mui ca axit khng c oxi (HCl, HBr...) vi cc kim loi t nhm trvtrc (Al3+, Mg2+, Na+, Ca2+, K+).

V d: in phn dung dch NaCl c mng ngn.

NaCl Na+ + Cl

H2O H+ + OH

Ti catot (): 1 2H2O + 2e H2 + 2OH

Ti anot (+): 1 2Cl Cl2 + 2ePhng trnh ion : 2Cl + 2H2O

pdd 2OH + H2 + Cl2

M S2 I Br Cl OH SO42, NO3

, ClO4

Cc ion bin phntrong dung dch

S2- S + 2e2X X2 + 2e

Cc ion khng b inphn trong dung dch

2H2O O2 + 4H+ + 4e

(Anot tan)4OH O2+ 2H2O + 4e

M Mn+ + ne


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Phng trnh phn t : 2NaCl + 2H2Opdd comang ngan 2NaOH + H2 + Cl2

(catot) (anot)

Nu khng c mng ngn, Cl2 sinh ra s tc dng vi NaOH to thnh nc Gia-ven :

2NaOH + Cl2 NaCl + NaClO + H2O

in phn nc:

+ in phn dung dch kim (NaOH, KOH...):

NaOH Na+ + OH

H2O H+ + OH

Ti catot (): 2 2H2O + 2e H2 + 2OH

Ti anot (+): 1 2OH O2 + 2H+ + 4e

Phng trnh in phn: 2H2Opdd 2H2 + O2

(catot) (anot)

+ in phn dung dch cc axit c oxi (v d H2SO4 long...):

H2SO4 2H+ + SO42

H2O H+ + OH

Ti catot (): 2 2H+ + 2e H2

Ti anot (+): 1 2H2O O2 + 4H+ + 4e

Phng trnh in phn: 2H2Opdd 2H2 + O2

(catot) (anot)

in phn dung dch mui ca cc axit c oxi (H2SO4, HClO4...) vi cc kim loi t nhm trvtrc (K+, Na+, Ca2+...):

V d: in phn dung dch Na2SO4:Na2SO4 2Na

+ + SO42

H2O H+ + OH

Ti catot (): 2 2H2O + 2e H2 + 2OH

Ti anot (+): 1 2H2O O2 + 4H+ + 4e

Phng trnh ion: 2H2Opdd 2H2 + O2

(catot) (anot)

(Trong qu trnhin phn, nng ion H3O+ khu vc anot tng v nngOH tng khuvc catot. Do , khu vc anot c phnng axit cn khu vc catot c phnng kim).

Nhn xt :Trong cc trng hp in phn dung dch mui Na2SO4, axit H2SO4, baz kimNaOH... bn cht l sin phn nc. Khi mui, axit, kim ch ng vai tr cht dn in.Lng cht (smol) cc cht trong dung dch khng thay i (nng cc cht tng dn do ncb in phn, thtch dung dch gim).

(Ch:-Trong dung dchin li nu c ion F v nc th H2O sbin phn.-Nu c ion R-COO khi b in phn: 2R-COO 2e = R-R + 2CO2).

c. in phn hn hp+Nu trong dung dch cht in li c cha nhiu ion ca nhng kim loi khc nhau (c nng

mol bng nhau) th catot s xy ra s kh nhng ion kim loi ny theo trnh t sau: Ion kim loi

no c tnh oxi ho mnh hn (ng sau trong dy thin ho) s b kh trc.


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+ Nu trong dung dch cht in li c nhng anion gc axit khc nhau cng khng cha oxi nh:Br, Cl, S2, I (c cng nng mol) th anion no c tnh kh mnh hn s b oxi ho trc. Trnanot s xy ra s oxi ho nhng anion trn theo trnh t:

S2, I, Br, Cl.

V d: in phn dung dch cha hn hp cc mui KBr, FeCl3, CuCl2, FeCl2. Hy vit th t

cc phn ng xy ra ti cc in cc.Phng trnh phn li:

KBr K+ + Br

FeCl3 Fe3+ + 3Cl

CuCl2 Cu2+ + 2Cl

FeCl2 Fe2+ + 2Cl

H2O H+ + OH

Th tin phn ti catot: (Cc m) Th t in phn ti anot: (Cc dng)

Fe3+ + 1e Fe2+

Cu2+ + 2e Cu

Fe2+ + 2e Fe

s kh nc 2H2O + 2e H2 + 2OH

2Br Br2 + 2e

2Cl Cl2 + 2e

s oxi ho nc 2H2O O2 + 4H+ + 4e

3. in phn vi anot (dng cc) tanNu khi in phn ta dng anot bng kim loi hoc hp kim th lc anot b tan dn do kim

loi b oxi ho thnh ion kim loi.V d: Khi in phn dung dch CuSO4 nu thay cc dng (anot) tr (Pt hay than ch) bng bn

ng th sn phm ca sin phn s khc.

CuSO4 Cu2+ + SO4

2

H2O H+ + OH

Ti catot (): Cu2+ + 2e Cu

Ti anot (Cu) (+): Cu Cu2+ + 2e

Cu2+(dd) + Cu (r) Cu (r) + Cu2+ (dd)

(anot-tan) (catot-bm)

Kt qu: Cu kim loi kt ta cc m (catot), khi lng catot tng, cc dng (anot) tan ra,khi lng anot gim, nng ion Cu2+ v SO4

2 trong dung dch khng bin i. Kt qu nh l

s vn chuyn Cu t anot sang catot.Trong cng nghip, ngi ta li dng tnh tan ca cc dng khi in phn tinh ch cc kimloi, nht l ng v m kim loi. Chng hn mun m mt kim loi ln trn mt vt no ,ngi ta vt cc m (catot) ri in phn dung dch mui ca kim loi vi cc dng (anot)lm bng chnh kim loi .

4. nh lng trong in phn

Cng thc Faraday :AIt

mnF

=

Trong :m : Khi lng cht thu c in cc (gam)

A : Khi lng mol ca cht thu c in cc

F : Hng s Faraay c gi tr bng 96500.


36/88



n : S electron m nguyn t hoc ion cho hoc nhn (s electron trao i)

I : Cng dng in (ampe)

t : Thi gian in phn (giy)

T cng thc Faraday ta c th bin i thnh :{

=

1442443Somol

Somol elect ron trao o i

m I t.n

A F

Vy ta c : elec tron trao oiI t

nF

=

V n l bn chu!Ti nghe cu chuyn nyVit Nam v ngi ta bo l stht. Ti khng bit iu c ththay khng; nhng ti bit nhng iu k lhn th xy rat nc ny.

J ohn MansurCho d c nh trc, nhng khi b tng vn ri xung tri tr m ci trong mt lng nh.Mt, hai a tr b cht ngay lp tc. Rt nhiu em khc b thng, trong c mt b gi khongtm tui.Dn lng yu cu th trn ln cn lin lc vi lc lng qun i Hoa K gip v mt y t.Cui cng, mt bc sv mt y t ngi M mang dng c n. H ni rng b gi b thng rtnng, nu khng c x l kp thi n s cht v b sc v mt mu.Phi truyn mu ngay. Ngi cho mu phi c cng nhm mu vi b gi. Mt cuc th mu nhanhcho thy khng c ai trong hai ngi M c nhm mu , nhng phn ln nhng a tr m ci bthng li c.

Ngi bc sni vi ting Vit l l, cn c y t th ni t ting Php lm bm. H kt hp vi nhau

v dng iu b, c ch c gii thch cho bn tr ang shi rng nu h khng kp thi truyn mucho b gi th chc chn n s cht. V vy, h hi c em no tnh nguyn cho mu khng.p li li yu cu l s yn lng cng vi nhng i mt mto. Mt vi giy tri qua, mt cnhtay chm chp, run ry gi ln, h xung, ri li gi ln.- , cm n. Chu tn g? c y t ni bng ting Php.- Hn cu b tr li.H nhanh chng t Hn ln cng, xoa cn ln cnh tay v cho kim vo tnh mch. Hn nm imkhng ni li no.Mt lt sau, cu b nc ln, song n nhanh chng ly cnh tay cn li che mt.

Ngi bc shi C au khng Hn?. Hn lc u nhng ch vi giy sau li c ting nc khc.Mt ln na, cu b c chng t l mnh khng khc. Bc shi kim c lm n au khng, nhng

cu b li lc u.By gith ting nc cch qung nhng ch cho ting khc thm, u u. Mt nhm nghin li,cu b t nguyn c nm tay vo ming ngn khng cho nhng ting nc thot ra.Cc nhn vin y t trnn lo lng. R rng l c iu g khng n ri. Va lc , mt n y tngi Vit n. Thy r v cng thng trn mt cu b, ch nhanh chng ni chuyn vi n, nghe nhi v tr li bng mt ging ht sc nh nhng.Sau mt lc, cu b ngng khc v nhn ch y t bng nh mt t v hoi nghi. Ch y t gt u. Vmt cu ta nhanh chng trnn nh nhm.Ch y t kh gii thch vi nhng ngi M: Cu b c ngh l mnh sp cht. N hiu nhm. Nnghcc v mun n cho ht mu cu sng b gi kia.- Vy ti sao n li t nguyn cho mu? ngi y t lc qun hiCh y t ngi Vit phin dch cu hi li cho cu b v nhn c cu tr li rt n gin: V nl bn chu.


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B. Phng php gii bi tp in phn

Phng php gii- Bc 1 :Tnh smol electron trao i trong qu trnh in phn (nu bi cho bit thi

gianin phn v cng dngin).

nelectron trao i = It96500

Trong : I l cng dngin tnh bng ampe ; t l thi gianin phn tnh bng giy.- Bc 2 : Xc nh thtkhtrn catot, thtoxi ha trn anot ca cc ion v H2O ; Vit

qu trnh khtrn catot v oxi ha trn anot theong thtu tin.- Bc 3 : p dng nh lut bo ton electron cho qu trnhin phn :

Smol electron trao i = Smol electron m cc ion dng v H2O nhn catot = Smolelectron m cc ion m v H2O nhnganot.Lu :

Phnng in phn nc trn cc in cc :+ Ti anot : 2H2O 4H+ + O2 + 4e+ Ti catot : 2H2O + 2e H2 + 2OH-

Trong qu trnhin phn, khi lng dung dch gimbng khi lng ca cc kh thot ra vkim loi sinh ra bm vo in cc.

Cc v dminh ha Dng 1 : in phn nng chyV d 1:in phn nng chy a gam mui A to bi kim loi M v halogen X thu c 0,96 gamM catot v 0,896 lt kh anot. Mt khc ho tan a gam mui A vo nc ri cho dung dch trn

tc dng vi AgNO3 d c 11,48 gam kt ta. X l halogen no ?A. F. B. Cl. C. Br. D. I.Hng dn gii

Gi cng thc ca mui A l MXn vi s mol l b, ta c phn ng :

2MXn pnc 2M + nX2

mol : b b nb

2

MXn + nAgNO3 M(NO3)2 + nAgX

mol : b nb

Suy ra :nb 0,896

0,042 22,4

nb(108 X) 11,48

= =

+ =

X=35,5. Vy halogen l clo.

p n B.


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V d 2: in phn nng chy Al2O3 vi anot than ch (hiu sut in phn 100%) thu c m kgAl catot v 67,2 m3 (ktc) hn hp kh X c t khi so vi hiro bng 16. Ly 2,24 lt (ktc) hnhp kh X sc vo dung dch nc vi trong (d) thu c 2 gam kt ta. Gi tr ca m l :

A. 54,0. B. 75,6. C. 67,5. D. 108,0.

Hng dn gii

Cch 1 :Phng trnh phn ng :

2Al2O3pnc 4Al + 3O2

C + O2ot CO2

2C + O2ot 2CO

CO2 + Ca(OH)2 CaCO3 + H2O

mol: 0,02 0,02

Trong qu trnh in phn nng chy oxit nhm, anot gii phng kh O2, oxi sinh ra s phn

ng vi anot than ch to ra CO, CO2 v c th c O2 d.t s mol ca CO, CO2, O2 d trong 67,2 m

3 hn hp kh X l x, y, z ta c :

x + y + z =67,2.1000

300022,4

= (1)

Mt khc t khi ca X vi hiro l 16 nn suy ra :

28x 44y 32z16.2 32

x y z

+ += =

+ +(2)

Thnh phn phn trm v s mol ca CO2 trong hn hp l :

y 0,02

x y z 0,1=+ + (3)

T (1), (2), (3) ta c :

x 1800

y 600

z 600

=

= =

2 3 2 2O trong A l O CO CO O

n n 2.n 2.n 1800 2.600 2.600 4200 mol= + + = + + = .

Trong oxit nhm :

Al

A l O A lO

n 2 2n .n 2800 mol m 2800.27 75600 gam 75, 6 kg.

n 3 3= = = = = =

Cch 2 :

XM 16.2 32 gam / mol= = Hn hp X c CO, CO2 v cn c th c O2 d.

V khi lng mol ca O2 l 32 m khi lng mol trung bnh ca hn hp X cng l 32 nnsuy ra khi lng mol trung bnh ca hn hp CO v CO2 cng bng 32.

p dng s ng cho cho hn hp CO v CO2 ta c :

COn 28 44 32 = 12

32

2COn 44 32 28 = 4 2

CO

CO

n 12 3

n 4 1 = =


39/88


40/88



Sdng phnng in phndng phn t

V d 3:Ngi ta iu ch H2 v O2 bng phng php in phn dung dch NaOH vi in cctr, cng dng in 0,67A trong thi gian 40 gi. Dung dch thu c sau in phn c khilng 100 gam v nng NaOH l 6%. Nng dung dch NaOH trc in phn l (gi thitlng nc bay hi khng ng k)

A. 5,08%. B. 6,00%. C. 5,50%. D. 3,16%.Hng dn gii

Bn cht ca phn ng in phn dung dch NaOH l phn ng in phn nc.

Ta c :2 2 2e t H O H

0,67.40.3600n 2n 4n 1 mol n 0,5 mol.

96500= = = = =

Phng trnh phn ng :

2H2O 2H2 + O2 (1)

mol: 0,5 0,5

Vy nng phn trm ca dung dch NaOH trc in phn l :

NaOH

100.6%C% .100 5,5%.

100 0,5.18= =

+

p n C.

V d 4: in phn (vi in cc tr) 200 ml dung dch CuSO4 nng x mol/l, sau mt thi gianthu c dung dch Y vn cn mu xanh, c khi lng gim 8 gam so vi dung dch ban u. Cho16,8 gam bt Fe vo Y, sau khi cc phn ng xy ra hon ton, thu c 12,4 gam kim loi. Gi trca x l

A. 2,25. B. 1,5. C. 1,25. D. 3,25.

Hng dn gii

Phng trnh phn ng :

2CuSO4 + 2 H2O pdd 2Cu + 2H2SO4 + O2 (1)

mol : 2a 2a 2a a

Theo (1) v gi thit ta c : 2a.64 + 32a = 8 a = 0,05 mol

Fe + H2SO4 FeSO4 + H2 (2)

mol : 0,1 0,1

Fe + CuSO4 FeSO4 + Cu (3)

mol : b b

Theo (2), (3) v gi thit ta c :16,8 (0,1 + b).56 + 64b = 12,4 b = 0,15 mol

Vy tng s mol ca CuSO4 ban u l : 2a + b = 0,25 mol x =0,25

1,25M0,2

= .

p n C.


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V d 5: in phn 150 ml dung dch AgNO3 1M vi in cc tr trong t gi, cng dng inkhng i 2,68A (hiu sut qu trnh in phn l 100%), thu c cht rn X, dung dch Y v khZ. Cho 12,6 gam Fe vo Y, sau khi cc phn ng kt thc thu c 14,5 gam hn hp kim loi vkh NO (sn phm kh duy nht ca N+5). Gi tr ca t l :

A. 0.8. B. 0,3. C. 1,0. D. 1,2.

Hng dn giiPhng trnh phn ng in phn :4AgNO3 + 2H2O 4Ag + 4HNO3 + O2

mol: x x

T phn ng in phn suy ra s mol ca HNO3 bng s mol ca AgNO3 phn ng.

t s mol ca AgNO3 tham gia phn ng in phn v AgNO3 d l x v y, ta c :

x + y = 0,15.

Dung dch Y gm x mol HNO3 v y mol AgNO3.

Cho Fe vo dung dch Y sau phn ng thu c hn hp kim loi nn Fe d, mui st trong

dung dch l Fe(II).Qu trnh oxi ha - kh :

4H+ + NO3- + 3e NO + 2H2O

mol: x 0,75x

Ag+ + e Ag

mol: y y y

Fe Fe2+ + 2e

mol: (0,375x + 0,5y) (0,75x + y)

Cn c vo gi thit, cc qu trnh oxi ha - kh v nh lut bo ton electron ta c :

12,6 (0,375x 0,5y).56 108y 14,5 + + = Gii phng trnh tm c x= 0,1; y = 0,05

Thi gian in phn l :96500.0,1

3600s 1h.2,68

= =

b. in phn dung dch cha hn hp cc cht tanSdng phnng xy ra trn cc in cc v nh lut bo ton electron

V d1:Cho mt dng in c cng dng in khng i i qua 2 bnh in phn mc ni tip,bnh 1 cha 100 ml dung dch CuSO4 0,01M, bnh 2 cha 100 ml dung dch AgNO3 0,01M. Bitrng sau thi gian in phn 500 giy th bn bnh 2 xut hin kh bn catot. Cng I, khi lng

Cu bm bn catot v th tch kh (ktc) xut hin bn anot ca bnh 1 l :A. 0,193A; 0,032 gam Cu; 5,6 ml O2. B.0,193A; 0,032 gam Cu; 11,2 ml O2.C. 0,386A; 0,64 gam Cu; 22,4 ml O2. D.0,193A; 0,032 gam Cu; 22,4 ml O2.

Hng dn gii:Khi cho dng in 1 chiu i qua 2 bnh in phn mc ni tip th s mol electron trao i ti

qua cc bnh in phn l nh nhau.

Theo gi thit th sau 500 giy th bnh 2 AgNO3 bin phnht nn :

nelectron trao i = Agn + = 0,001 mol Cng dng in I =96500.0,001

500= 0,193A.

bnh 1 :Khi lng Cu bm vo catot l 0,001.64 0, 0322

= gam .


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Th tch O2 l0,001

.22, 4 5, 64

= ml.

p n A.

V d 2:in phn (in cc tr) dung dch X cha 0,2 mol CuSO4 v 0,12 mol NaCl bng dngin c cng 2A. Th tch kh (ktc) thot ra anot sau 9650 giy in phn l :

A. 2,240 lt. B. 2,912 lt. C. 1,792 lt. D. 1,344 lt.Hng dn gii

Th t oxi ha trn anot : Cl- > H2O

nelectron trao i =2.9650

0,296500

= mol

Cc qu trnh oxi ha :

2Cl- Cl2 + 2e

mol : 0,12 0,06 0,12

2H2O

4H

+

+ O2 + 4emol : 0,02 (0,2 0,12)

Th tch kh (ktc) thot ra anot l (0,06 + 0,02).22,4 = 1,792 lt.

p n A.

V d 3:in phn c mng ngn 500 ml dung dch cha hn hp gm CuCl2 0,1M v NaCl 0,5M(in cc tr, hiu sut in phn 100%) vi cng dng in 5A trong 3860 giy. Dung dchthu c sau in phn c kh nng ho tan m gam Al. Gi tr ln nht ca m l :

A. 4,05. B. 2,70. C. 1,35. D. 5,40.

Hng dn gii

Th t oxi ha trn anot : Cl

-

> H2OTh t kh trn caot : Cu2+ > H2O


0,296500

= mol > 2. 2Cun + = 0,1 mol nn Cu2+ ht v catot nc b in

phn mt phn.

Phn ng in phn ti catot :

Cu2+ + 2e Cu

mol : 0,05 0,1

2H2O + 2e H2 + 2OH

-

mol : (0,2 0,1) 0,1Phn ng ca nhm vi dung dch sau in phn :

2Al + 2H2O + 2OH- 3H2 + 2AlO2

-

mol : 0,1 0,1Khi lng Al phn ng l 0,1.27 = 2,7 gam.

p n B.


43/88



V d4:in phn 200 ml dung dch Y gm KCl 0,1M v Cu(NO3)2 0,2M vi cng dng in5A trong thi gian 1158 giy, in cc tr, mng ngn xp. Gi s nc bay hi khng ng k. gim khi lng ca dung dch sau khi in phn l :

A. 3,59 gam. B. 2,31 gam. C. 1,67 gam. D.2,95 gam.

Hng dn gii

Th t oxi ha trn anot : Cl- > H2OTh t kh trn caot : Cu2+ > H2O


0,0696500

= mol

Ta thy :nelectron trao i > Cln nn ti anot Cl- v H2O b oxi ha.

nelectron trao i < 2. 2Cun + nn ti catot ch c Cu2+b kh.

Qu trnh oxi ha :

2Cl- Cl2 + 2e

mol : 0,02 0,01 0,022H2O 4H

+ + O2 + 4e

mol : 0,01 (0,06 0,02) = 0,04

Qu trnh oxi kh :

Cu2+ + 2e Cu

mol : 0,06 0,03

gim khi lng ca dung dch sau khi in phn bng tng khi lng cc sn phm khthot ra trn cc in cc v khi lng kim loi bm vo catot l :

mgim =2 2Cl O Cu

m m m+ + = 0,01.71 + 0,01.32 + 0,03.64 = 2,95 gam.

p n D.

V d 5:in phn 100 ml hn hp dung dch gm Fe(NO3)3 1M, Cu(NO3)31M v HCl 2M viin cc tr c mng ngn xp cng dng in l 5A trong 2 gi40 pht 50 giy. Gi s nc

bay hi khng ng k. gim khi lng ca dung dch sau khi in phn l :


Hng dn giiTh t oxi ha trn anot : Cl- > H2O

Th t kh trn caot : Fe3+ > Cu2+ > Fe2+ > H2O

nelectron trao i =5.(2.3600 40.60 50)

0,596500

+ += mol

Qu trnh kh trn catot:

Fe3+ + 1e Fe2+

mol : 0,1 0,1 0,1

Cu2+ + 2e Cu

mol : 0,1 0,2 0,1

2H+ + 2e H2

mol : 0,2 0,2 0,1

Nh vy ti catot va kh ht H+ ca HCl.


44/88


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Sdng phnng in phndng phn t

V d 7:in phn dung dch gm 7,45 gam KCl v 28,2 gam Cu(NO3)2 (in cc tr, mng ngnxp) n kh khi lng dung dch gim i 10,75 gam th ngng in phn (gi thit lng nc

bay hi khng ng k). Tt c cc cht tan trong dung dch sau in phn l :A. KNO3 v KOH. B. KNO3, KCl v KOH.

C. KNO3 v Cu(NO3)2. D. KNO3, HNO3 v Cu(NO3)2.Hng dn gii

3 2KCl Cu(NO )n 0,1 mol, n 0,15 mol.= =

Ti anot, th t oxi ha : Cl- > H2O.

Ti catot, th t kh : Cu2+ > H2O.

Phng trnh phn ng in phn :

2KCl + Cu(NO3)2 Cl2 + Cu + 2KNO3

mol: 0,1 0,05 0,05 0,05

Khi lng dung dch gim = 0,05.64 + 0,05.71 = 6,75 < 10,75. Suy ra Cu(NO3)2 tip tc bin phn.

2H2O + 2Cu(NO3)2 O2 + 2Cu + 4HNO3

mol: 2x x 2x

Khi lng dung dch gim = 6,75 + 32x + 2x.64 = 10,75 x = 0,025

Tng s mol Cu(NO3)2 phn ng l 0,1 < 0,15, suy ra Cu(NO3)2 cn d.

Vy trong dung dch sau phn ng c cc cht : KNO3, HNO3 v Cu(NO3)2.

p n C.

V d 8:in phn dung dch cha m gam hn hp 2 mui CuSO4 v NaCl bng in cc tr n

khi nc b in phn c hai in cc th dng li. Dung dch thu c sau in phn hon tanva 1,6 gam CuO v anot ca bnh in phn c 448 ml kh bay ra (ktc). Gi tr ca m l :


Hng dn giiTi anot, th t oxi ha : Cl- > H2O.

Ti catot, th t kh : Cu2+ > H2O.

Cn c vo th t kh v oxi ha trn cc in cc ta thy : Lc u CuSO4 tham gia in phncng vi NaCl. Sau nu CuSO4 ht trc th NaCl sin phn cng vi nc, ngc li nu

NaCl ht trc th CuSO4 sin phn cng vi nc.

Phng trnh phn ng in phn :

2NaCl + CuSO4 Cl2 + Cu + Na2SO4 (1)

mol: 2x x x

V dung dch sau in phn ha tan c 0,02 mol CuO nn suy ra dung dch ny phi c tnhaxit. Vy ngoi phn ng (1) cn c phn ng in phn CuSO4 cng vi H2O.

2H2O + 2CuSO4 O2 + 2Cu + 2H2SO4 (2)

mol: 2y y 2y

Phn ng ca CuO vi dung dch sau in phn :

CuO + H2SO4 H2O + CuSO4 (3)

mol: 2y

2yKh thot ra anot l Cl2 v O2 c tng s mol l 0,02 mol.


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Vy theo cc phn ng v gi thit ta c :

x y 0,02 x 0,01

2y 0,02 y 0,01

+ = =

= =

Tng khi lng CuSO4 v NaCl ban u l :

m = 2.0,01.58,5 + (0,01+0,01.2).160 = 5,97 gam.p n C.V d9:in phn (cc in cc tr) 0,8 lt dung dch A cha HCl v Cu(NO3)2 vi cng dng2,5 ampe. Sau thi gian t thu c 3,136 lt kh (ktc) mt cht kh duy nht anot. Dung dchsau in phn phn ng va vi 550 ml dung dch NaOH 0,8M v thu c 1,96 gam kt ta.Tnh nng mol ca cc cht trong dung dch A v thi gian t.

Hng dn giiTi anot, th t oxi ha : Cl- > H2O.

Ti catot, th t kh : Cu2+ > H+ > H2O.

Cn c vo th t oxi ha trn anot v gi thit ta thy 3,136 lt kh (ktc) thot ra trn trn

anot l Cl2.Phng trnh phn ng :

2HCl + Cu(NO3)2 Cl2 + Cu + 2HNO3 (1)

mol: 0,28 0,14 0,14 0,28

Dung dch sau phn ng in phn phn ng vi NaOH thu c kt ta chng t c Cu(NO3)2d, ngoi ra cng c th cn HCl d.

HNO3 + NaOH NaNO3 + H2O (2)

mol: 0,28 0,28

HCl + NaOH NaCl + H2O (3)

mol: x xCu(NO3)2 + 2NaOH 2NaNO3 + Cu(OH)2 (4)

mol: 0,02 0,04 0,02

Theo cc phn ng v gi thit ta c tng s mol ca NaOH tham gia phn ng l :

0,28 + x + 0,04 = 0,44 x = 0,12.

Vy nng mol ca cc cht trong dung dch A l :

3 2

0,12 0,28 0,14 0,02[HCl ] 0,5M; [Cu(NO ) ] 0,2M .

0,8 0,8

+ += = = =

Thi gian in phn := = = =

2electron trao oi el ectron trao oi Cl

I t 96500.0,14.2n van 2n t 10808 giay.

96500 2,5


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BI 4 : N MN KIM LOI

A. L THUYTI. n mn kim loi

Sn mn kim loi l sph hu kim loi hoc hp kim do tc dng ca cc cht trong mitrng xung quanh. l mt qu trnh ho hc hoc qu trnh in ho trong kim loi b oxiho thnh ion dng.

M Mn++ne

C hai kiu n mn kim loi l n mn ho hc v n mn in ho.

1. n mn ho hcn mn ho hc l qu trnh oxi ho - kh, trong cc electron ca kim loi c chuyn trc

tip n cc cht trong mi trng.My mc dng trong cc nh my ho cht, nhng thit b ca l t, ni hi, cc chi tit

ca ng c t trong b n mn do tc dng trc tip vi cc ho cht hoc vi hi nc

nhit cao. Nhit cng cao, kim loi b n mn cng nhanh.2. n mn in ho hc (n mn in ha)

n mnin ho l qu trnh oxi ho - kh, trong kim loi b n mn do tc dng ca dungdch chtin li v to nn dng electron chuyn di tcc mn cc dng.a. Th nghim n mn in ho

Nhng thanh km v thanh ng khng tip xc vi nhau vo cc ng dung dch H2SO4 long.Ni thanh km vi thanh ng bng dy dn cho i qua mt vn k. Kim vn k quay, chng t cdng in chy qua. Thanh Zn b mn dn, thanh Cu c bt kh thot ra.

Gii thch : in cc m (anot), km b n mn theo phn ng :

Zn Zn2+

+2eIon Zn2+i vo dung dch, cn electron theo dy dn sang in cc ng.

in cc dng (catot), ion H+ ca dung dch H2SO4 nhn electron bin thnh nguyn t Hri thnh phn t H2 thot ra :

2H+ + 2e H2

b. C chn mn in ha st (hp kim st trong khng khm)Ly s n mn st lm th d. Trong khng kh m, trn b mt ca st lun c mt lp nc rt

mng ho tan O2 v kh CO2 trong kh quyn, to thnh mt dung dch cht in li. St v cc tpcht (ch yu l cacbon) cng tip xc vi dung dch to nn v s pin rt nh m st l anot vcacbon l catot.

Ti anot, st b oxi ho thnh ion Fe2+ : Fe Fe2+ + 2eCc electron c gii phng chuyn dch n catot.

Ti vng catot, O2 ho tan trong nc b kh thnh ion hiroxit : O2 + 2H2O + 4e 4OH

Cc ion Fe2+ di chuyn t vng anot qua dung dch in li n vng catot v kt hp vi ionOH to thnh st(II) hiroxit. St(II) hiroxit tip tc b oxi ho bi oxi ca khng kh thnhst(III) hiroxit, cht ny li phn hu thnh st(III) oxit.

G st mu nu, c thnh phn chnh l Fe2O3.xH2O.

c. iu kin xy ra sn mn in ho+ Cc in cc phi khc cht nhau, c th l cp 2 kim loi khc nhau hoc cp kim loi

vi phi kim.+ Cc in cc phi tip xc trc tip hoc gin tip vi nhau qua dy dn.


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+ Cc in cc cng tip xc vi dung dch cht in li.

Thiu mt trong ba iu kin trn skhng xy ra sn mnin ho.I I. Chng n mn kim loi

S n mn kim loi gy tn tht to ln cho nn kinh t quc dn. Hng nm chng ta phi sacha, thay th nhiu chi tit ca my mc, thit b dng trong cc nh my v cng trng, cc

phng tin giao thng vn ti,...Mi nm, lng st, thp b g chim n gn 1/4 lng c sn xut ra. V vy, chng n mn

kim loi l cng vic quan trng cn phi lm thng xuyn ko di thi gian s dng ca ccmy mc, vt dng lm bng kim loi. Di y l mt vi phng php chng n mn kim loi.

1. Phng php bo vbmtDng nhng cht bn vng i vi mi trng ph ngoi mt nhng vt bng kim

loi nh bi du m, sn, m, trng men,... St ty l st c trng thic, tn l st c trngkm. Cc vt bng st thng c m niken hay crom.

2. Phng php in hoNi kim loi cn bo v vi mt kim loi hot ng hn to thnh pin in ho v kim loi

hot ng hn b n mn, kim loi kia c bo v. Th d bo v v tu bin lm bng thp vv tu (phn chm di nc), ng thp dn nc, dn du, dn kh t di t, ngi ta lp vomt ngoi ca thp nhng khi km. Kt qu l km b nc bin hay dung dch cht in li trongt n mn thay cho thp.

Hai cch din ging

Ngy xa, c mt ng Hong Rp n triu mt nh tin tri ti hi ng s sng c bao nhiunm.

Nh tin tri ni : B h s sng lu, sng lu ti cNgi s chng kin c cc ci cht ca cccon Ngi.ng Hong tc gin v li ni sc phm, ra lnh cho qun smang ra chm u. ng lin triu mtnh tin tri khc v cng hi cu hi v tui th ca ng.

Nh tin tri ny tr li nh sau : Tha B H, Ngi s sng lu, Ngi s sng th hn tt c mingi trong gia nh Ngi ng Hong hoan h v tng rt nhiu tin cho nh tin triHai nh tin tri u ni ln s tht, nhng mt li ni th bc trc, v mt li ni th uyn chuynhn.Cng mt stht, nhng cch din ging v cch dng tngkhn kho th dlt tai hn.


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BI 5 : IU CH KIM LOI

A. L THUYTI. Nguyn tciu chkim loi

Trong thin nhin, ch c mt s t kim loi nh vng, platin,... tn ti dng t do, hu ht cckim loi cn li u tn ti dng hp cht. Trong hp cht, kim loi tn ti di dng ion dngMn+.

Mun iu ch kim loi, ta phi kh ion kim loi thnh nguyn t.

Vy : Nguyn tc iu chkim loi l khion kim loi thnh nguyn t.Mn+ + ne M

I I. Cc phng php iu chkim loi1. Phng php nhit luyn

Nhng kim loi c hot ng trung bnh nh Zn, Fe, Sn, Pb c iu ch bng phngphp nhit luyn, ngha l kh ion kim loi trong hp cht nhit cao bng cc ch

4 dang toan vo co 12 on thi dhcd

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