[kiemnghiemthucpham.blogspot.com]_thuc hanh phan tich dinh luong

8/2/2019 [Kiemnghiemthucpham.blogspot.com]_Thuc Hanh Phan Tich Dinh Luong

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Khoa Hoa Giao trnh thc hanh Phan tch nh lng

336

NOI DUNG THC TAP

Cahai hephan tch chuyen nganh eu lam 18 bai thc hanh

- HeCao ang: Thc hanh tbai 2 en bai 19.- Hetrung cap: Thc hanh bai 1, 3 en bai 19.


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CHNG I: PHNG PHAP PHAN T CH THET CH

Phan 1: PHNG PHAP AXIT BAZ

Bai 1: PHA CHECAC DUNG DCH

I . KYTHUAT PHA CHEHOACHAT:

1. Bai t nh mau:

Can pha V(lt) dung dch A nong oCM. Tnh khoi lng ran (A) valng nccan lay.

Somol cua A cotrong dung dch = V.CM (mol).

Nen khoi lng A cotrong dung dch = V.C

M

.MA (g): lakhoi lng can canGiasxem spha tron gia (A) vaH2O khong costhay oi venhiet lng hayvetnh chat cua cac chat, tc noi cach khac, trong spha tron nay thetch cua chat ran(A) khong anh hng en thetch chung cua dung dch.

Bai nay gii thieu mot phng phap pha ung nong oanh san cua mot dungdch makhong can can chnh xac. ekhac phuc v iec khocan c chnh xac giatrsocan V.CM .MA (g), machcan can gan chnh xac (bang can phan tch vi lng can) laV.CM . MA m (g) (vi m lagiatrsai sotrong khi can so vi lng can yeu cau) chovao beaker. Nen can d mot t so vi lng can can: V.CM . MA + m (g)

Them V(l t) H2O vao coc, th nong odung dch cotrong coc sela:

C1M =V

m

.M

].M[V.C

A

AM =

V

m

.MC

A

M

(mol/lt)

Rorang giatrnay sai biet vi nong ocan pha laCM mot lngV

m

.MA

.

Noi cach khac dung dch va pha xong conong o"am" hn nong odung dchcan pha. ecoc nong ocan pha th phai pha loang i bang 1 mot lng H2O cothetch la:

Ap dung quy tac ng cheo:

OHV

V

2

=CC

C

1

C

CCVV

OH

1

.2

=C

m

.MA

CM1 - CM

CMV dung dch A coCM1

V' dung dch H2O coOM

CM


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2. Kythuat pha :

- Can [V.CM . MA m] lng ran (A) trong mot coc khosach.

- Cho vao coc mot lng H2O la V +C

m

.MA

(lt)

- Hut ra lai lng thetch dung dch laV (l t) th dung dch A seconong olaCMTh nghiem 1: Pha chedung dch H2C2O4 0.1N

Sinh vien phai ttnh toan lng can thc tecua H2C2O4.2H2O, co% c ghi trenbao b cua hoa chat tng ng tai phong th nghiem, epha c 100ml dung dch acid0.1N, khi can phai lay chnh xac en 0.0002g, coc can loai 100ml, phai sach, khovaconhiet ocan bang vi phong can, sau khi can, them nc cat aloai CO2 (nc catun soi 10 phut, etrong bnh kn vanguoi en nhiet ophong) khoang 3040ml , dungua thuy tinh khuay cho tan, chuyen vao bnh nh mc 100ml theo ua thuy tinh quapheu, dung nc cat trang coc 3 lan, moi lan 10ml, dung bnh tia ra ua vanh mcti vach, ay nap bnh nh mc, ao ngc bnh 45 lan, chao nhechc khong xocmanh bnh.

Th nghiem 2: Pha chedung dch NaOH 0.1N

V NaOH lamot chat rat dehut am, hap thuCO2 moi trng v vay nodechayra, vacho san pham sai biet. Do o, viec can NaOH trong khong kh theo mot giatrchnh xac cho trc laieu khong lam c trong ieu kien bnh thng. Noi cach khac,khong thepha mot dung dch NaOH conong ochnh xac nh mong muon, machphac dung dch NaOH conong oxap xgiatrnh trc. ededang trong viec hieuchnh bang cach pha loang, can phai can l n hn lng can tnh theo lythuyet motlng nho(tuyet oi khong nen can d quanhieu roi lay ngc ra trlai), khi can phai

can that nhanh.Chang han epha che100ml dung dch NaOH 0,1N th can khoang 0,4(g) NaOH

ran trong can kythuat. Roi hoa tan NaOH trong coc can bang 50ml nc, dung ua thuytinh khuay cho tan, chnguoi, sau olam tiep nh phan pha dung dch axit.

Hoac cothedung ong chuan NaOH 0,1N epha thanh 1 lt dung dch NaOH 0,1N

Th nghiem 3: Pha dung dch HCl 0,1N

Khac vi hai dung dch tren, dung dch HCl c pha tHCl am ac, can tnh thetch HCl am ac can lay labao nhieu epha c 100ml conong o0.1N, sau ochuan bsan mot coc loai 100ml cocha san 50ml nc cat. Lay pipet hut chnh xac the

tch atnh, nhanh chong nhung ngap au pipet vao trong coc achuan b, sau othatt, dung bnh tia ra sach pipet, nc ra cho luon vao coc pha, sau ochuyen vao nhmc nh phan tren.

Hoac cothedung ong chuan HCl 0,1N epha thanh 1 l t dung dch HCl 0,1N

I I .PHA CHEMOT SODUNG DCH:

Cac dung dch di ay lanhng v dumau cho mot cach pha tng ng nham taomot sodung dch hay chuyen dung. Moi dung dch cha khoang 50mg ion/ml.


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1. Dung dch cha khoang 50mg cation/mL

- Hg22+: Hg2(NO3)2.2H2O 70g/l, them 2 giot HNO3 ac.

- Ag+ : AgNO3 20g/l, them 2 giot HNO3 ac, ng trong lothuy tinh mau.- Pb2+ : Pb(NO3)2 80g/l, them 2 giot HNO3 ac.- Hg2+ : Hg(NO3)2.1/2H2O 85g/l, them 2 giot HNO3 ac

- Fe3+ : Fe(NO3)3.H2O 32g/l , pha trong NO3

0.1MFeCl3.6H2O 240g/, pha trong HCl 0.1M

- Fe2+ : FeSO4.7H2O 248g/l, pha trong H2SO4 0.1M- Bi3+ : Bi(NO3)3.5H2O 115g/, pha trong HNO3 0.1M- Al 3+ : Al(NO3)3.9H2O 695g/l, pha trong HNO3 0.1M- Cr3+ : Cr(NO3)3.9H2O 385g/l, pha trong HNO3 0.1M- Sn4+ : SnCl4.5H2O 145g/l, pha trong HNO3 0.1M- Sb2+ : SbCl3 95g/l, pha trong HCl (1:1)- Ba2+ : Ba(NO3)2 95g/l

BaCl2 90g/l- Sr2+ : Sr(NO3)2.4H2O 160g/l- Ca2+ : Ca(NO3)2.4H2O 160g/l

CaCl2.6H2O 261g/l- Mg2+ : Mg(NO3)2.6H2O 530g/l- Mn2+ : Mn(NO3)2.6H2O 260g/l

MnCl2.4H2O 180g/lMnSO4.7H2O 252g/l

- Cu2+ : Cu(NO3)2.3H2O 190g/l, pha trong HNO3 0.1M- Co2+ : Co(NO3)2.6H2O 246g/l, pha trong HNO3 0.1M- Ni2+ : Ni(NO3)2.6H2O 248g/l, pha trong HNO3 0.1M- Cd2+ : Cd(NO3)2.4H2O 137g/l, pha trong HNO3 0.1M- Zn2+ : Zn(NO3)2.6H2O 230g/l

2. Dung dch cha khoang 50mg anion/mL

- SO42 : Na2SO4.10H2O 167.5g/l

- SO32 : Na2SO3.7H2O 157.6g/l

- S2O32 : Na2S2O3.5H2O 111g/l

- CO32 : Na2CO3 88.5g/l

- PO43 : Na2HPO4 49g/l

- SiO32 : Na2SiO3 61g/l

Na2SiO3.5H2O 136g/l

- Cl : NaCl 86.6g/l- S2 : Na2S.H2O 376g/l- NO3

: NaNO3 68.5g/l- CH3COO

: NaCH3COO.3H2O 115g/l


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Bai 2: NH L NG AXIT MANH - BAZ MANH

I . CHUAN B:

- Chuan bcac dung dch sau: NaOH 0.1N, 2N, 5N- Dung dch H2C2O4 0,1N- Dung dch HCl 0,1N- Dung dch Na2B4O7 0,1N- Cac chth: phenolphtalein, MO, MR

1. Pha chedung dch H2C2O4 0.1N:

Sinh vien phai t tnh toan lng can thc tecua H2C2O4.2H2O, cop% (otinhkhiet) c ghi tren bao b cua hoa chat tng ng tai phong th nghiem, chang han, epha c 100ml dung dch acid 0.1N, khi can phai lay chnh xac en 0.0002g, coc can

loai 100ml, phai sach, khovaconhiet ocan bang vi phong can. Sau khi can, themnc cat aloai CO2 (nc cat un soi 10 phut, etrong bnh kn vanguoi en nhiet ophong) khoang 3040ml, dung ua thuy tinh khuay cho tan, chuyen vao bnh nh mc100ml theo ua thuy tinh qua pheu, dung nc cat trang coc 3 lan, moi lan 10ml, dungbnh tia ra ua vanh mc ti vach, ay nap bnh nh mc, ao ngc bnh 45 lan,chao nhechkhong xoc manh bnh.

Chuy: Cac dung dch c sdung trong quatrnh phan tch nh lng tai Giaotrnh nay eu c tnh theo nong oCN 0,05 - 0,1 N. ay chtrnh bay cach phachung oi vi cac chat dehoa tan trong nc vaquatrnh hoa tan toa hay thu nhietkhong ang ke. Cach pha vi cac chat khac cung vi kythuat tng t, chkhac lng

can vathetch bnh nh mc, khong nen pha trc tiep tren bnh nh mc. Cac dungdch goc phai c pha het sc can than vachnh xac v noquyet nh en o ungcua phep nh lng.

2. Pha chedung dch NaOH 0.1N:

V NaOH lamot chat rat dehut am, hap thuCO2 moi trng v vay nodechayra, vacho san pham sai biet. Do o, viec can NaOH trong khong kh theo mot giatrchnh xac cho trc laieu khong lam c trong ieu kien bnh thng. Noi cach khac,khong thepha mot dung dch NaOH conong ochnh xac nh mong muon, machphac dung dch NaOH conong oxap xgiatrnh trc. ededang trong viec hieu

chnh bang cach pha loang, can phai can ln hn lng can tnh theo l ythuyet motlng nho(tuyet oi khong nen can d quanhieu roi lay ngc ra trlai), khi can phaican that nhanh.

Chang han epha che100ml dung dch NaOH 0,1N th can chnh xac khoang0,4(g) NaOH ran bang can kythuat. Roi hoa tan NaOH trong coc bang 50ml nc, dungua thuy tinh khuay cho tan, chnguoi, sau olam tiep nh phan pha dung dch axittren.

Hoac cothedung ong chuan NaOH 0,1N pha thanh 1 l t.


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- Cho dung dch NaOH CN va xac nh tren, vao buret: nhottdung dchNaOH xuong erlen cocha mau cho en khi dung dch chuyen tkhong mau sangmau hong nhat. Ghi thetch NaOH anhoxuong.

- Tthetch o c 3 mau, tnh nong odung dch HCl.

Th nghiem 2:

Lap lai th nghiem 1 vi chthMR, so sanh vi trng hp hieu chnh bang chth

phenolphtalein.Th nghiem 3:

Lap lai th nghiem 1 vi chth MO, so sanh vi trng hp hieu chnh bangphenolphtalein.

Th nghiem 4:

- Hut 10 ml Na2B4O7 0,1N vao erlen + 20 ml nc cat vi 3 giot MR .- Nap dung dch HCl va xac nh CN tren, vao buret. Tburet nhodung dch HCl

xuong erlen cocha mau cho en khi dung dch chuyen tmau vang chanh sangmau hong ta .Ghi thetch HCl tieu ton .

- Tthetch HCl, tnh chnh xac lai nong ocua HCl vaso sanh vi trng hp hieuchnh bang dung dch NaOH.

Cau hoi :

1. Hay tnh khoang nong odung dch HCl trong 4 th nghiem tren vi otin cay95%

2. V sao th nghiem 4 khong theoi vtr : tren buret cha Na2B4O7 vaerlen chaHCl ?

Chuy: bai nay chgii thieu 3 cach pha chedung dch vaphep hieu chnhchung. Con nhng bai sau, phai tpha checac dung dch chuan, con dung dch mau lado giao vien pha ttrc giao cho sinh vien.

Qua buoi thc hanh sinh vien xac nh nong ocua dung dch mau vatrali caccau hoi eviet bao cao cho giao vien.

Giao vien nen thu bai bao cao sau moi buoi th nghiemCac ket qua bao cao nhlng, eu c tnh cho otin cay = 95%. V thegiao vien nen hng dan lai chosinh vien cac phan:

- Cach can hoachat- Cach hieu chnh can khoi lng vathetch o- Tnh sai sothong ke

- Tnh sai socho phep chuan othetchCuoi moi buoi Th nghiem, cac sinh vien nop cac lomau ac ra sach, codan

nhan sotocua mnh egiao vien chuan bcac mau buoi th nghiem sau.Nong odung dch can bao cao cua sinh vien cothec gi yla:

- Vi chuan oAcid - baz : CN hay CM- Vi chuan ooxy hoakh: CN hay CM- Vi chuan otao phc: CN hay CM- Vi chuan otao tua vaphep khoi lng: C% hay Cppm.


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Bai 3: NH LNG N AXIT YEU - BAZ MANHNH LNG N ACI D MANH - BAZ YEU

I . CHUAN B:- Chuan bcac dung dch sau: NaOH 0,1N- Dung dch CH3COOH 0,1N- Cac chth: Phenolphtalein, MO, MR

I I .NH LNG ACID YEU - BAZ MANH:

Th nghiem 1:

Dung dch mau ladung dch CH3COOH CN (0,1N - 0,5N) c giao vien phatrc, sinh vien khong c biet trc

- Hut chnh xac 10 ml dung dch mau CH3COOH bang pipet bau 5 ml cho vao erlen,lam 3 mau. Them vao moi mau khoang 20 ml nc cat + 3 giot PP, lac nhe.

- Nap dung dch NaOH 0,1N len buret 25 ml. Tburet, nhotng giot NaOH xuongerlen cho en khi dung dch chuyen tkhong mau sang hong nhat (ben trong 10giay). Ghi thetch NaOH tieu ton. Cung lam tng tvi 2 erlen con lai.

- Tthetch o c 3 mau, tnh nong odung dch CH3COOH

Th nghiem 2:

Dung dch mau ladung dch NaOH CN (0,1N - 0,5N) c giao vien pha trc,sinh vien khong c biet trc

- Hut 10 ml dung dch NaOH CN + 20 ml nc cat +3 giot pp cho vao erlen, lam 3mau- em chuan obang CH3COOH 0,1N cho en khi dung dch chuyen tmau hong

tm sang khong mau. Ghi thetch CH3COOH 0,1N tieu ton. Tthetch o c 3 mau, tnh nong odung dch NaOH

Cau hoi:1. Khi pha them nc cat vao erlen trong bc 2 th nghiem 1, colam thay oi so

ng lng cua dung dch HCl khong? Cho biet cac tnh song lng thnghiem nay?

2. Bc nhay chuan ocua viec chuan dung dch CH3COOH bang dung dch NaOH

cog khac vi bc nhay trong viec chuan dung dch HCl bang dung dch NaOH?Giai thch?

3. Khi tien hanh chuan oaxit yeu bang baz manh neu thay chthpp bang MRhoac MO coc khong? Gia MR vaMO cogay anh hng g khac nhau khong?(echng minh, sinh vien can thc nghiem ngay bang cach thay Phenolphtaleinbang MO vaMR)

I I I . CHUAN ON AXIT M ANH - BAZ YEU:


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- Hoachat : dung dch chuan HCl 0,1N- ChthMR ,nc cat

Th nghiem 1:

Dung dch mau ladung dch NH3 CN (0,1N - 0,5N) c giao vien pha trc, sinhvien khong c biet trc

- Hut 10ml dung dch mau cho vao bnh non 250ml + 20ml nc cat, 3 giot MR(0.1% trong con)- Nap dung dch HCl 0,1N vao buret. Chuan obang dung dch HCl en khi dung

dch tmau vang chuyen sang mau ocam, ghi thetch HCl tieu ton- Tthetch o c 3 mau, tnh nong odung dch NH3.- Thay chthPhenolphtalein bang MR vaMO, nhan xet.

Th nghiem 2:

Dung dch mau ladung dch NH3 CN (0,1N - 0,5N) c giao vien pha trc, sinhvien khong c biet trc- Hut 10 ml HCl chuan 0,1N vao erlen + 20 ml nc cat vi 3 giot MR , lam 3 mau- Nap dung dch mau NH3 CN len buret. Tburet nhodung dch NH4OH 0,1 N

xuong erlen cocha HCl cho en khi dung dch chuyen tmau hong sang mauvang chanh. Ghi thetch NH4OH tieu ton (lam 3 mau).

- Tthetch o c 3 mau, tnh nong odung dch NH3

Cau hoi:

1. Trong th nghiem 1, khi thay Phenolphtalein bang MO vaMR th cac giatr V(NH3) thu c nao cosai sobenhat ? Giai thch?

2. V sao trong 2 th nghiem bi cung dung dch HCl vaNH3, cung chthMR, nhnglai coschuyen mau ngc nhau?

3. Vi 2 cach chuan okhac nhau 2 th nghiem, cho biet th nghiem nao cho phepxac nh nong oNH3 chnh xac hn? Giai thch?


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Bai 4: NH LNG A ACID VAHON HP ACID

I . CHUAN B

- Hoachat: dung dch chuan NaOH 0,1N va5N- ChthMR, Phenolphtalein, nc cat

I I .NH LNG ACID A CHC H 3PO4:

Th nghiem 1:

Dung dch mau ladung dch H3PO4 CN (0,1N - 0,5N ) c giao vien pha trc,sinh vien khong c biet trc- Hut 20 ml mau + 10 ml H2O cat + 1 giot MO 0,1 % vao erlen, lam 3 mau.- Chuan obang dung dch NaOH 0,1N cho en khi dung dch chuyen tmau o

sang ocam. Ghi thetch NaOH tieu ton (at laVMO)

- Tiep tuc cho vao mau 3 giot PP, roi chuan otiep bang dung dch NaOH, ghi thetch NaOH tieu ton lan sau (at laVPP). Lam tng tcho 2 mau con lai.

- Tthetch o c 3 mau, tnh nong odung dch H3PO4 CNTh nghiem 2:

Dung dch mau ladung dch H3PO4 CN (0,1N - 0,5N ) c giao vien pha trc,sinh vien khong c biet trc- Hut 10 ml dung dch H3PO4 CN bang pipet bau 5 ml cho vao erlen (lam 3 mau),

them vao moi mau khoang 10 ml nc cat + them 1 giot MO 0,1%, lac nhe.- Nap dung dch NaOH 0,1N len buret 25 ml. Tburet, nhotng giot NaOH xuong

erlen cho en khi dung dch chuyen tmau ocam sang vang cam. Ghi thetchNaOH tieu ton (VMO)- Cho tiep tuc vao mau 3 giot PP. Chuan otiep bang NaOH cho en khi dung dch

chuyen tmau vang cam sang hong cam. Ghi thetch NaOH tieu ton (VPP). Lamtng tcho 3 mau con lai

- Tthetch o c 3 mau, tnh nong odung dch H3PO4 CN

Cau hoi:

1. anh giaket qua tm c 2 TN nay. Giai thch?2. Neu thay MO bang Bromcrezol luc 0,1% / Etanol 20% (BCL) th ket qua cothay

oi khong? Giai thch?

II I. NH LNG HON HP AXI T HCl + H3PO4:

- Hoachat: dung dch chuan NaOH 2N- ChthMO, Phenolphtalein, nc cat

Dung dch mau ladung dch hon hp [HCl + H3PO4 ] (0,1N - 0,5N) c giao vienpha trc, sinh vien khong c biet trc- Hut 5 ml hon hp mau + 10 ml H2O cat + 1giot MO 0,1 %.


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Bai 5: NH LNG A BAZ VAHON HP BAZ

I . CHUAN B:

- Hoachat: dung dch chuan HCl 0.1N, dung dch NaHCO3 0.1N, dung dch NaOHchuan 0.1N, BaCl2 0.1N

- ChthMR, BromCresol luc, PP, nc cat

I I .NH LNG BAZ A CHC Na2CO3:

Dung dch mau ladung dch Na2CO3 CN (0,1N - 0,5N) c giao vien pha trc,sinh vien khong c biet trc- Hut 5 ml dung dch mau Na2CO3 CN + 10 ml nc cat + 3 giot pp cho vao erlen,

lam 3 mau, dung dch secomau hong am. Roi hut 5 ml NaHCO3 0,1N + 10 mlnc cat + 3 giot PP cho vao erlen th4 elam bnh chng (comau hong tmnhat).

- Chuan ocac mau bang dung dch HCl 0,1N cho en khi dung dch chuyen tmauhong tm am sang mau cua bnh chng. Ghi thetch HCl tieu ton (Vpp) .

- Them tiep tuc 1 giot MO vao mau, dung dch chuyen sang mau hong tm anh cam,roi cho tng giot HCl ttren buret nhoxuong cho en khi dung dch chuyen sangcam.

- em un soi mau khoang 2-3 phut, enguoi. Roi tiep tuc chuan obang HCl 0,1Ncho en khi dung dch chuyen tcam sang ocam. Ghi thetch HCl tieu ton(VMO) .

- Tthetch o c 3 mau, tnh nong odung dch Na2CO3Cau hoi:1. V sao viec chuan odung dch Na2CO3 lai dung dung dch NaHCO3 lam chng e

so sanh mau tai iem tng ng?2. Thiet lap cong thc tnh nong oNa2CO3. Giai thch v sao phai dung en hai ch

th?

I I I . NH LNG HON HP NaOH VANa2CO3:

- Hoachat: dung dch chuan HCl 0,1N, dung dch NaHCO3 0,1N- Chth: Phenolphtalein, MO, nc cat

Dung dch mau lahon hp dung dch (NaOH + Na2CO3) CN (0,1N - 0,5N) cgiao vien pha trc, sinh vien khong c biet trc.

Th nghiem 1:

- Hut chnh xac 5 ml hon hp mau NaOH + Na2CO3 CN va10 ml nc cat aloaiboCO2 + 3 giot PP cho vao erlen (lam 3 mau). Can hut 5 ml NaHCO3 0,1 N+ 10ml nc cat + 3 giot PP cho vao erlen 4 elam bnh chng (comau hong tm).

- Sau otien hanh chuan ocac mau bang dung dch HCl chuan 0,1N cho en khidung dch chuyen sang mau cua bnh chng. Ghi thetch HCl tieu ton (Vpp ).


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- Them tiep tuc 3 giot MO vao mau roi cho tng giot HCl ttren buret nhoxuongcho en khi dung dch chuyen tmau ocam sang vang cam

- em un soi mau khoang 2 - 3 phut ,enguoi. Roi tiep tuc chuan obang HClchuan 0,1N cho en khi dung dch chuyen tvang cam sang hong cam. Ghi thetch HCl tieu ton (VMO)

- Tthetch o c 3 mau, tnh nong odung dch hon hp

Th nghiem 2:

- Cho 3 mau hon hp dung dch vao 3 bnh non, moi bnh 10ml mau + khoang 20mlnc aloai het CO2 + 3 giot MO, chuan bang dung dch HCl cho en khi dungdch chuyen tmau vang sang mau da cam, ghi thetch HCl tieu ton tc laVMO.

- Lai lay 3 mau cho vao 3 bnh non, moi bnh 10ml mau + 20ml nc aloai hetCO2 + 20ml dung dch BaCl2 1N, un nong khoang 50

oC, enguoi + 3giotPhenolphtalein. Chuan bang dung dch HCl cho en khi dung dch chuyen tmauhong sang khong mau, ghi thetch HCl tieu ton tc laVPP.

Cau hoi:

1. Trong hai th nghiem tren, iem khac biet quan trong cua chung lag? Vietphng trnh phan ng minh hoa. Tnh CN cua tng chat trong hon hp 2 thnghiem?

2. So sanh VPP vaVMO trong chuan onh l ng Na2CO3 vahon hp NaOH +Na2CO3 th nghiem 1? Nhan xet, toa ra cong thc tnh ham lng %? Tnhsai song vi hai chth, boqua otan cua CO2?

3. V sao phai un soi khi giai oan chuan ovi chthMO?

IV. NH LNG HON HP NaHCO3 + Na2CO3:

Th nghiem 1:

Dung dch mau lahon hp dung dch (NaHCO3 + Na2CO3) CN (0,1N - 0,5N) cgiao vien pha trc, sinh vien khong c biet trc- Hut 5 ml hon hp mau cho vao erlen + 10 ml nc cat + 2 giot MO (lam 3 mau).

Roi chuan obang dung dch HCl chuan 0,1 N cho en khi dung dch chuyen sangocam. Ghi thetch HCl tieu ton (VMO).

- Hut 5 ml hon hp mau cho vao erlen + 10 ml nc cat + 10 ml NaOH 0,1 N+ 10ml BaCl2 0,1 N (lam 3 mau). em un nong khoang 50 600C, enguoi, khongcan loc ket tua roi cho 3 giot PP. Sau oem chuan obang dung dch HCl chuan0,1 N cho en khi dung dch mat mau hong tm. Ghi thetch HCl tieu ton (Vpp ) .

- Tthetch o c 3 mau, tnh nong ohon hp dung dchTh nghiem 2:

Dung dch mau lahon hp dung dch (NaHCO3 + Na2CO3) CN (0,1N - 0,5N) cgiao vien pha trc, sinh vien khong c biet trc.- Hut chnh xac 10 ml hon hp mau + 10 ml nc cat + 3 giot Phenolphtalein cho

vao erlen (lam 3 mau). Can hut 10 ml NaHCO3 0,1 N + 10 ml nc cat +3giot PPcho vao erlen 4 elam bnh chng (comau hong tm).


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- Sau otien hanh chuan ocac mau bang dung dch HCl chuan 0,1N cho en khidung dch chuyen tmau hong tm am sang mau cua bnh chng. Ghi thetchHCl tieu ton (Vpp).

- Them tiep tuc 1 giot MO vao mau roi cho tng giot HCl ttren buret nhoxuongcho en khi dung dch chuyen tmau vang cam sang hong cam.

- em un soi mau khoang 2-3 phut, enguoi. Roi tiep tuc chuan obang HCl

chuan 0,1N cho en khi dung dch chuyen sang hong cam. Ghi thetch HCl tieuton (VMO)- Tthetch o c 3 mau, tnh nong ohon hp dung dch

Cau hoi:

1. Neu skhac biet gia hai phng phap ac ap dung trong 2 th nghiem tren.2. Th nghiem nao cho ket quacosai sobehn? Giai thch

Chuy: V bai sau cocac dung dch c chuan btrc t nhat 1 ngay, nen cuoibuoi thc hanh nay, sinh vien can hoi giao vien etap pha trc dung dch nay nhamchuan bcho buoi thc hanh sau.


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BAI 6: NH LNG MUOI

I . CHUAN B:

- Hoachat: cac dung dch NaOH 0,1N- HCl 0,1 N, HNO3 1:1, KNO3 0,03 N, NH4NO3 0,5 N- (NH4)6Mo7O24 15%- Chth: Phenolphtalein, MR

I I .NH LNG HAM LNG PHOTPHAT:

Dung dch mau ladung dch H3PO4 CN (0,1N - 0,5N) c giao vien pha trc,sinh vien khong c biet trc.

Lay 5 bnh erlen, coghi sonhan etien theo doiBnh 1 va5: Dung pipet bau hut 10 ml mau H3PO4 + 5 ml HNO3 1:1 + 5 ml

NH4NO3 3%, un nong khoang 60 700C, them tt20 ml (NH4)6Mo7O24 10%, khuaynhe, elang 2 gi.

Bnh 3 va4: Dung pipet bau hut 10 ml mau H3PO4 + 5 ml HNO3 1:1 + 5 mlNH4NO3 3% + 20 ml (NH4)6Mo7O24 10%, lac nhe, un nong khoang 60 70

0C, elang2 gi.

Bnh 2: Dung pipet bau hut 10 ml mau H3PO4 + 5 ml HNO3 1:1 + 5 ml NH4NO33% + 20 ml (NH4)6Mo7O24 10%, lac nhe, un nong khoang 60 70

0C, elang qua em(bai 4 cac sinh vien achuan bdung dch nay roi).- Loc ket tua bang giay loc bang xanh, v hat ket tua rat mn varat detroi theo nc

trang nen khong c odch loc qua1/3 pheu, sau khi chuyen het ket tua len

pheu, mot t ket tua van con bam tren thanh erlen, dung NH4NO3 3% trang erlen3 lan (moi lan la5 ml), sau odung KNO3 3% trang vachuyen ket tua len pheu,chthc hien oi vi cac bnh 1, 3, 4 con cac bnh 2, 5 th dung NH4NO3 3% etrang hoan toan thay cho KNO3 3%, quatrnh trang cac bnh cho en khi nctrang trung tnh (thbang giay pH) ,vara tua cho en khi tua het axit (thbanggiay pH).

- Chuyen ket tua cung giay loc vao ung cac erlen asdung trc o,cho themnc cat vao erlen valac manh etua khong con bam tren giay loc. Ketiep chovao moi erlen 3 giot Phenolphtalein

- Chuan bang dung dch NaOH 0,1N nhoxuong erlen ehoa tan tua cho en khi

dung dch chuyen tmau vang chanh sang mau hong nhat (neu lng ket tuanhieu th cothedung NaOH conong ocao hn), sau ocho d them khoang 2 mlNaOH na, ghi tong thetch NaOH asdung. Lac eu, em chuan lng NaOHd bang dung dch HCl 0,1 N cho en khi dung dch mat mau hong nhat. Ghi thetch HCl tieu ton.

- Tthetch o c 3 mau, tnh nong o PO43-.


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Cau hoi:

1. Giai thch vai trocua cac hoa chat asdung trong bai thc tap?2. Hay thiet lap cong thc tnh nong oPO4

3?3. anh giaviec nh lng H3PO4 bang dung dch NaOH (bai 3) va(bai 5). Rut ra

nhan xet g ve2 cach nh lng athc hanh?

I I I . XAC NH HAM LNG MUOI AMONI:Dung dch mau ladung dch NH4Cl CN (0,1N - 0,5N) c giao vien pha trc,

sinh vien khong c biet trc- Dung pipet bau hut 5 ml NH4Cl 0,1 N + 25ml NaOH chuan 0,1 N cho vao erlen

(lam 3 mau).- un tren bep ien khoang 5 -10 phut oi vi moi mau, cho en khi can con 1/ 3

thetch ban au, thxem abay het hi NH3 cha (bang giay quytam t), sauoenguoi

- Them 2 giot MR. em chuan obang dung dch chuan HCl 0,1N cho en khidung dch chuyen tvang chanh sang hong tm. Ghi thetch HCl tieu ton.

- Tthetch o c 3 mau, tnh nong odung dch NH4Cl.Cau hoi:

1. Viet cac phan ng xay ra vacong thc tnh cho moi trng hp xac nhCH3COOH, NH3, NH4Cl?

2. Tnh sai song vi tng chthsdung khi xac nh CH3COOH vaNH3?


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Phan 2: PHNG PHAP OXI HOA KH

Bai 7: CHUAN OPEMANGANATNH LNG Fe2+, H2O2 VANO2

-

I . CHUAN B:

- Dung dch H2SO4 2N- Dung dch chuan KMnO4 0,05N- Dung dch H2C2O4 0,05N

- Dung dch H2SO4 2N- Dung dch H3PO4 am ac- Hon hp bao vezymmerman

I I .NH LNG Fe2+:

Th nghiem 1: Xac nh chnh xac nong odung dch K MnO4

- Hut 10ml H2C2O4 0,05N vao bnh non + 5ml H2SO4 2N, un nong 80-90

o

C trong 3phut, lac eu. Lam 3 mau trong 3 bnh non 250ml trong bnh non 250ml .- Chuan bang dung dch KMnO4 en khi dung dch comau hong nhat- Tthetch o c 3 mau, tnh nong odung dch KMnO4

Th nghiem 2:

Dung dch mau ladung dch Fe2+ (0,01N - 0,05N) c giao vien pha trc, sinh vienkhong c biet trc nong o.- Hut 10 ml mau + 1ml H3PO4 am ac + 5ml H2SO4 2N lac eu, lam 3 mau trong 3

bnh non 250ml trong bnh non 250ml.- Chuan bang dung dch KM nO4 0,05N en khi dung dch comau hong nhat.- Tthetch o c 3 mau, tnh nong odung dch Fe2+.

Cau hoi:

1. Tai sao khi chuan oFe2+ bang KMnO4 chuan khong can phai un nong?2. Giai thch vai trocua cac dung dch H2SO4 vaH3PO4 trong th nghiem?

I I I . NH LNG HAM LNG CUA NO2-:

Dung dch mau ladung dch KNO2 CN (0,01N - 0,05N) c giao vien pha trc,sinh vien khong c biet trc nong o.- Hut 5ml KMnO4 0,05N vao erlen + 1giot H2SO4 0.01N (chnh vepH 5-6), lac eu

un nong tren bep cach thuy (40- 50oC) trong 3 phut, l am 3 mau trong 3 bnh non250ml.

- Chuan bang dung dch mau en khi dung dch comau hong nhat (luc au canchuan onhanh cho ti khi comau hong nhat th chuan ocham cho en khi matmau)

- Tthetch o c 3 mau, tnh nong odung dch NO2-.


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Cau hoi:

1. Tai sao khi bat au chuan oth ta phai chuan nhanh vaphai un nong dung dchtrc khi chuan o?

2. Cothechuan onitrit bang KMnO4 trong moi trng trung tnh hay kiem haykhong?

3. Khi chuan othay xuat hien ket tua nau th can phai xlynh thenao?

IV. NH LNG HAM LNG CUA H2O2:

Dung dch mau ladung dch H2O2 (0,01N - 0,05N) c giao vien pha trc, sinhvien khong c biet trc nong o.- Hut 5ml mau + 5ml H2SO4 2N, lac eu, lam 3 mau trong 3 bnh non 250ml trong 3

bnh non 250ml .- Chuan bang dung dch chuan KMnO4 0.05N en khi dung dch comau hong nhat

(ben trong 30 giay), ghi thetch KMnO4 0.05N tieu ton.- Tthetch o c 3 mau, tnh nong odung dch H2O2 cotrong mau.

Cau hoi:

1. Neu thay oi vtr cac chat ngc lai trong th nghiem: coc ng KMnO4 vaburetng dung dch mau, th ket quacothay oi khong? Giai thch?

2. Vi dlieu thu c tth nghiem, hay tnh sai sophep chuan onay?3. V sao khi chuan oaxi t Oxal ic, Nitri t can phai un nong, con chuan oSat II va

Hydro peoxyt th khong can un nong?Chuy: V bai sau codung dch c chuan btrc t nhat 1 ngay, nen cuoi buoi

thc hanh nay, sinh vien can hoi giao vien etap pha trc dung dch K2Cr2O7 cho baith nghiem sau?


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Bai 8: CHUAN OPEMANGANATNH LNG Fe3+, Cr6+

I . CHUAN B:

- Dung dch KMnO4 0,05N- Dung dch H2C2O4 0,05N- Dung dch SnCl2 10%- Dung dch H2SO4 2N- Dung dch K2Cr2O7 10%- Dung dch em acetat pH = 5.5- Dung dch AgNO3 0,05N- Dung dch HCl 1:1

- Dung dch H2SO4 10%

- Dung dch CH3COOH 10%- Dung dch Amonioxalat 1%- Dung dch AgNO3 0.1N- ChthMO 0.1%- ChthFeroin- CH3COOH am ac- ChthMR- Dung dch Zymmerman

I I .NH LNG Fe3+:

Dung dch mau ladung dch Fe3+ (0,01N - 0,05N) c giao vien pha trc, sinhvien khong c biet trc nong o.- Hut 10ml mau + 5ml H2SO4 6N, lac vaun soi dung dch 60-70

oC- Nhotng giot SnCl2 10% cho en khi dung dch mat mau vang- Khi dung dch achuyen mau th nhothem 2giot na valam nguoi dung dch bang

cach pha loang dung dch bang nc cat en tong thetch 100ml .- Cho 5ml HgCl2 5% vao, dung dch coket tua dai lua trang (neu coket tua trang

bong, hoac xam en phai lam lai tau).- Them 10ml hon hp Zymmerman.- Chuan bang dung dch KMnO4 0,05N ti dung dch comau hong nhat ben

Chuy: neu mau laquang sat, muoi colan Sat II th ham lng laSat tong chkhong phai laSat III

Cau hoi:

1. Khi xac nh Fe3+, giai oan cho SnCl 2 vao, v sao neu thay ket tua xam en thphai hut mau khac lam lai tau? Tai sao phai cho d 2 giot SnCl 2 sau khi dungdch mat mau vang? Mau vang olag?

2. Vai trocua hon hp Zymmerman?

I I I . NH L NG HAM LNG CUA Cr 6+:

Dung dch mau ladung dch Cr2O72- (0,01N - 0,05N) c giao vien pha trc,

sinh vien khong c biet trc nong onong o.- Hut 5ml mau vao erlen + 10 ml Fe2+ 0,05N + 5ml H2SO4 2N, lac eu, un nong

70-80oC trong 3 phut, lam 3 mau trong 3 bnh non 250ml trong 3 bnh non 250ml.- Chuan obang dung dch KMnO4 0,05N, iem tng ng nhan c khi dung

dch chuyen tmau xanh lacay sang mau hong nhat.- Tthetch o c 3 mau, tnh nong odung dch Cr2O7

2-.


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Cau hoi:

1. a ra cac cong thc tnh vachng minh?2. Giai thch quy trnh kythuat bang phng trnh phan ng?

IV. NH LNG ION Ca2+:(phng phap the)

Dung dch mau ladung dch Ca2+ (0,01N - 0,05N) c giao vien pha trc, sinh

vien khong c bi et trc nong o- Hut 10ml dung dch mau + 20ml (NH4)2C2O4 0,05N + 5ml CH3COOH 10% + 1

giot MO 0,1% + 50 giot NH4OH 2N echnh dung dch vemau vang (chthMO),lam 3 mau trong 3 bnh non 250ml trong 3 bnh non 250ml .

- un soi 5 phut khuay eu (lac) eket tua lang tren bep cach thuy 45 phut- Loc dung dch qua giay loc bang xanh bang kythuat loc gan chuyen het phan

dung dch len giay loc ,gan ket tua bang dung dch Amonioxalat 1% (3 lan moi lan10ml)

- Ra ket tua tren giay loc bang nc cat nong cho het Ion C2O42- (kiem tra ahet

C2O42- bang CaCl2)

- Hoa tan ket tua ngay tren giay loc bang 30 ml H2SO4 10%.- Thu dung dch qua loc vathem nc cat en thetch 50ml. un nong 80-90oC- Chuan obang dung dch KMnO4 0,05Ncho en khi comau hong ben 1phut- Tthetch o c 3 mau, tnh nong odung dch Ca2+

Cau hoi:

1. Viet ay ucac phan ng xay ra trong qui trnh xac nh, vai trocua tng hoa chatasdung?

2. Thiet lap cong thc tnh nong oCa2+?


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Bai 9: PHNG PHAP IODNH LNG VITAMIN C, SO3

2-

I . CHUAN B:- K2Cr2O7 0,05N- H2SO4 am ac- Dung dch KI 5%- Na2S2O3 ran- Dung dch Iot pha trong KI 0,05N- Dung dch Iot 0,05N- Dung dch em acetat

- CH3COOH 2N- KI 5%- KSCN 10%- H2SO4 4N- (NH4)2MoO4 3%- Chthhotinh bot 1%

I I .NH LNG DUNG DCH Na2S2O3:

Th nghiem 1: Xac nh chnh xac nong odung dch Na2S2O3

- Pha che250ml dung dch Na2S2O3 0,05N vacho them 0.1g Na2CO3- Hut 5ml K2Cr2O7 0,05N + 40ml nn cat + 1ml H2SO4 am ac + 5ml KI 5% lac

nheay kn eyen 10 phut trong toi, lam 3 mau trong 3 bnh non 250ml trong 3bnh non 250ml ekiem tra.

- Chuan bang dung dch Na2S2O3 cho ti khi dung dch comau vang rm, sau othem 5 giot hotinh bot roi chuan tiep bang Na2S2O3 cho ti khi dung dch mat mauxanh dng (Vml)

- Tthetch o c 3 mau, tnh nong odung dch Na2S2O3

Th nghiem 2: Xac nh chnh xac nong oI 2- Can 2.5 gam KI + 1.5 gam I2 + 10ml nc cat, lac vatron eu cho Iot tan, neu Iot

cha tan het th them mot t KI, sau ochuyen vao bnh nh mc 250ml , dungnc cat nh mc ti vach, chuyen vao bnh cha mau nau conut nham esdung.

- Dung pipet lay chnh xac 5ml Na2S2O3 0,05N + 5ml em Acetat + 5 giot hotinhbot 1% lac, lam 3 mau trong 3 bnh non 250ml trong 3 bnh non 250ml ekiemtra.

- Chuan odung dch thu c bang dung dch I2 mi pha en khi xuat hien mauvang nau (coanh xanh ben)

- Tthetch o c 3 mau, tnh nong odung dch I2.

Cau hoi:

1. V sao khi pha dung dch Na2S2O3 phai cho them lng 0,1g Na2CO3?2. V sao phai ay kn vaeyen trong bong toi trc khi hieu chnh nong o

Na2S2O3?

I I I . NH LNG VITAM IN C: (Axit Ascobic)


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Dung dch mau ladung dch acid Ascobic (0,01N - 0,05N) c giao vien phatrc, sinh vien khong c biet trc nong onong o- Hut 10ml mau + 10ml nc cat + 5ml H2SO4 6N + 5giot hotinh bot 1%- Chuan obang dung dch I2 0,05N en khi dung dch comau- Tthetch o c 3 mau, tnh nong odung dch Vitamin C

Cau hoi:

1. Viet phng trnh phan ng xay ra trong quatrnh th nghiem?2. iem tng ng trong phep chuan oI2 nay, comau g? Giai thch?

IV. NH L NG HAM LNG SUNFIT:

Dung dch mau lamau SO32- pha tNa2SO3 (97%) (0,01N - 0,05N) c giao vien pha

trc, sinh vien khong c biet trc.- Hut 5ml mau vao erlen + 10ml I2 0,05N ay kn lac eyen trong toi 5 phut, lam 3

mau trong 3 bnh non 250ml trong 3 bnh non 250ml.- Chuan lng I2 d bang dung dch Na2S2O3 0,05N en khi dung dch mat mau nau

coanh xanh- Tthetch o c 3 mau, tnh nong odung dch SO32-

Cau hoi:

1. V sao phai ay kn dung dch trong bong toi? Neu dung ngay coanh hng gkhong?

2. So sanh hai cach nh lng bang Iod vaPemanganat?


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BAI 10: PHNG PHAP IOD - CROMATNH LNG H2O2, Cu

2+, Pb2+

I . CHUAN B:- Dung dch K2Cr2O7 0,05N- H2SO4 am ac- KI 5%- Na2S2O3 ran- Dung dch Iot pha trong KI 0,05N- Dung dch Iot 0,05N

- KI 5%- KSCN 10%- H2SO4 4N- (NH4)2MoO4 3%- Chthhotinh bot1%- Dung dch em Acetat- CH3COOH 2N

Chuy: Dung dch Na2S2O3 c pha vanh lng nh bai trc.

I I .NH LNG HAM LNG Cu

2+

:Dung dch mau ladung dch Cu(NO3)2 (0,01N - 0,05N) c GVHD pha trc, HS

- SV khong c biet trc nong o- Hut 5ml mau +1ml CH3COOH (hay 5ml CH3COOH 2N) + 5ml KI 5% lac e

yen trong toi 10 phut . Lam 3 mau trong 3 bnh non 250ml trong 3 bnh non 250ml .- Chuan bang dung dch Na2S2O3 0,05N en mau vang nhat- Them 5 giot hotinh bot 1% chuan tiep en gan mat mau xanh tm- Them 5nl KSCN lac kychuan tiep en khi mat mau xanh- Tthetch o c 3 mau, tnh nong odung dch Cu2+

Cau hoi:

1. Giai thch quy trnh nh lng Cu2+ bang phan ng minh hoa?2. V sao phai them KSCN vao giai oan cuoi cua quatrnh chuan okhi xac nh

Cu2+, ml cua Cu2+ trong bai nay labao nhieu? Giai thch v sao Cu2+ lai phan ng

vi I

makhong xay ra theo chieu ngc lai? KSCN d nhieu th coanh hng g?KI d nhieu th cophan ng nao xay ra?

I I I . NH L NG HAM LNG H2O2:

Dung dch mau ladung dch H2O2 (0,01N - 0,05N) c giao vien pha trc, sinhvien khong c biet trc nong onong o

- Hut 5ml mau H2O2 vao erlen + 5ml H2SO4 2N + 5ml KI 5% + 2giotAmonimolypdat ay bnh lac eyen trong toi 10 phut, lam 3 mau trong 3 bnh non250ml.

- Chuan lng Iot sinh ra bang dung dch Thiosunfat en khi dung dch mat mauxanh.

- Tthetch o c 3 mau, tnh nong odung dch H2O2.

Cau hoi:


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1. Viet ay ucac phng trnh phan ng athc hien trong bai thc tap ?2. Neu xac nh hydropeoxyt nong ocao th coanh hng en ket quakhong, giai

thch?

IV. NH L NG CH BANG PHNG PHAP CROMAT:

Dung dch mau ladung dch Pb2+ (0,01N - 0,05N) c giao vien pha trc, sinh

vien khong c biet trc nong o- Hut 10ml mau + 5ml dung dch em acetat (thlai bang giay pH vaieu chnh vepH =5 - 6), them 5ml K2Cr2O7 10% elang tua qua em lam vi 3 mau trong 3coc 250ml

- Loc ket tua bang giay loc bang xanh vi kythuat loc gan, sau moi lan chuyennc loc len giay loc lamot lan nc cat xen ke, ket tua trong coc c chuyenlen pheu loc tng lng nho, moi lan kem theo 5ml K2Cr2O7 1%.

- - Dung dung dch K2Cr2O7 1% aacid hoa bang acid CH3COOH 0,1N ra tua, rahet tua bang nc cat nong cho en het ion Cromat. Thbang dung dch AgNO30,05N hoa tan ket tua tren giay loc bang HCl 1:1 nong khoang 20ml ra sach het

acid tren giay loc thbang giay pH.- - Them 2ml HCl 1:1 + 2ml H3PO4 am ac +nc cat sao cho tong thetch khoang100ml + 3giot Feroin

- Chuan bang dung dch Fe2+ cho en khi dung dch comau nau o.- Tthetch o c 3 mau, tnh nong odung dch Ch.

Cau hoi:

1. Viet ay ucac phng trnh phan ng trong bai tap?2. Giai thch ay uvai trocua tng hoa chat asdung trong bai thc tap?


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Phan 3: PHNG PHAP CHUAN OPHC CHAT

Bai 11: NH LNG Ca2+ - Mg2+

I . CHUAN B:

- Dung dch em pH =10- Dung dch chuan Mg2+ 0,01M- NaOH 2N- Dung dch EDTA 0,01M.- Chth: ETOO

I I .XAC NH NONG OCUA DUNG DCH EDTA:

- Hut 10ml dung dch chuan Mg2+ 0,01M + 5ml dung dch em pH = 10 + 0,01gETOO (chuan bmot bnh elam mau trang vi thetch tng ng bnh mau vacac hoa chat tng t, chthay dung dch Mg2+ bang nc cat), lam 3 mau trong 3bnh non 250ml

- Chuan ocac bnh bang dung dch EDTA mi pha cho en khi dung dch vachuyen mau tmau onho sang mau xanh luc. Ghi cac thetch EDTA cua mauthat vamau trang

- Tthetch o c 3 mau, tnh nong odung dch EDTA

I I I . NH LNG Ca2+:

Dung dch mau ladung dch Ca(NO3)2 (0,01M - 0,05M) c giao vien pha trc,sinh vien khong c biet trc

Th nghiem 1:

- Hut 10 ml dung dch mau (chnh mau vepH = 9 -10 bang cach cho NH4OH vao) +5 ml em pH = 10 vat chthETOO + 10 ml nc cat cho vao er len (lam 3 mau).

- em chuan obang dung dch EDTA 0,01M cho en khi dung dch chuyen tmauonho sang xanh cham. Ghi thetch EDTA tieu ton.

- Tthetch o c 3 mau, tnh nong odung dch Ca2+

Th nghiem 2:

- Hut 10 ml dung dch Ca2+ + 5 ml NaOH 2N vat chthMurexit cho vao erlen(lam 3 mau).

- em chuan obang dung dch EDTA 0,01M cho en khi dung dch chuyen tmauonho sang tm hoa ca. Ghi thetch EDTA tieu ton.

- Tthetch o c 3 mau, tnh nong odung dch.Chuy: Vi mot mau comoi trng axit hoac kiem manh, phai dung axit hoac

baz eieu chnh en gan giatrpH qui nh roi mi cho em vao, trng hp vi ch


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thmurexit, thetch NaOH 2N phai tnh thetch phuhp sao cho a vec pH = 12,gan iem tng ng can them NaOH 2N.

Cau hoi:

1. Giai thch cac mau sac cotrong thc nghiem?2. Th nghiem nao cho ket quagan ung hn, giai thch?

IV. NH LNG Mg2+:Dung dch mau ladung dch Mg(NO3)2 (0,01M - 0,05M) c giao vien pha trc,

sinh vien khong c biet trc- Hut 10 ml dung dch mau (chnh vepH = 9 -10 bang cach cho NH4OH vao) + 5 ml

em pH = 10 vat chthETOO + 10 ml nc cat cho vao erlen (lam 4 mau, trongo1 mau chng).

- em chuan obang dung dch EDTA 0,01M cho en khi dung dch chuyen tmauonho sang xanh cham. Ghi thetch EDTA tieu ton. Tthetch o c 3 mau,tnh nong odung dch Mg2+

V. NH LNG Ca2+ + Mg2+ TRONG HON HP:Th nghiem 1:

Dung dch mau lahon hp Ca2+ vaMg2+ (0,01M - 0,05M) c giao vien phatrc, sinh vien khong c biet trc nong o.- Hut 10ml hon hp dung dch mau + 5ml dung dch em + 0,01g chthETOO, l am

3 mau trong 3 bnh non 250ml . Chuan bmot bnh elam mau trang vi thetchtng ng bnh mau vacac hoa chat tng t, chthay dung dch mau bang nccat.

- Chuan ocac bnh bang dung dch EDTA: dung dch va chuyen tmau onhosang mau xanh luc. Tthetch o c 3 mau, tnh nong odung dch mau.

Th nghiem 2:

Dung dch mau lahon hp Ca2+ vaMg2+ (0,01M - 0,05M) c giao vien phatrc, sinh vien khong c biet trc nong o- Hut 10ml dung dch mau + 5ml dung dch NaOH 2N + 0,01g chthMurexit, l am 3

mau trong 3 bnh non 250ml. Chuan b mot bnh elam mau trang vi thetchtng ng bnh mau vacac hoa chat tng t, chthay dung dch mau bang nccat.

- Chuan ocac bnh bang dung dch EDTA: dung dch va chuyen tmau onhosang mau tm hoa ca. Tthetch o c 3 mau, tnh nong ocua tng dung

dch Ca2+

vaMg2+

.Cau hoi:

1. Viet ay ucac phan ng atien hanh trong bai thc tap? Cho biet ETOO pHtrong qui trnh dang H2Ind

2, EDTA laH2Y2.

2. Giasthetch cua dung dch xac nh la50ml copH = 2, hay tnh can them baonhieu ml NaOH 2N ecopH = 12?


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Bai 12: NH LNG Zn2+, Fe3+, Al3+

VAHON HP Al3++ Fe3+

I . CHUAN BCAC DUNG DCH CHO BAI THC TAP:- Dung dch em acetat pH =5,5- Dung dch EDTA 0,01M- Dung dch NH3 2 N- Chth: Bromcresol luc, axit Sunfosali cilic

I I .NH LNG DUNG DCH Zn2+:

Dung dch mau ladung dch Zn2+ 0,01M - 0,05M) c giao vien pha trc, sinhvien khong c biet trc nong o

Th nghiem 1:- Hut 10ml dung dch chuan EDTA 0,01M + 5ml dung dch em acetat + 3 giot ch

thXylenon da cam, lam 3 mau trong 3 bnh non 250ml- Chuan bmot bnh elam mau trang vi thetch tng ng bnh mau vacac

hoa chat tng t, chthay dung dch mau bang nc cat.- Chuan ocac bnh bang dung dch mau cho en khi dung dch va chuyen mau t

mau vang sang mau hong tm.- Tthetch o c 3 mau, tnh nong odung dch Zn2+.

Th nghiem 2:

- Hut 10 ml dung dch mau (chnh mau vepH = 5 - 6 bang cach cho NH4OH vao) +5 ml em pH = 5,5 + 3 giot Xylenol da cam + 10 ml nc cat cho vao erlen, lam 3mau va1 mau trang

- Chuan obang dung dch EDTA 0,01M: dung dch chuyen tmau ocam sangvang cam.

- Tthetch o c 3 mau, tnh nong odung dch Zn2+.Chuy: Can bao ngay nong oZn2+ atm c cho giao vien ec anh gia

iem vaong thi, giao vien secho ket qua nong onay nham thc hien tiep cac thnghiem sau.

Cau hoi:1. Th nghiem nao cothecho ket quat sai sohn. Giai thch?2. Giai thch schuyen mau trong cac th nghiem tren?

I I I . NH LNG DUNG DCH Fe3+:

Dung dch mau ladung dch Fe3+ (0,01N - 0,05N) c giao vien pha trc, sinhvien khong c biet trc nong o


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- Hut 10 ml dung dch chuan EDTA, chnh mau vepH = 2 bang cach cho ttdungdch NH4OH vao 3 giot chth axit Sunfosalicilic lam 3 mau trong 3 bnh non250ml.

- Pha them 1 mau trang elam mau oi chng.- Chuan obang dung dch mau: dung dch chuyen tkhong mau sang nau o.- Tthetch o c 3 mau, tnh nong odung dch Fe3+.

IV. NH LNG Al3+:

Dung dch mau ladung dch Al3+ (0,01M - 0,05M) c giao vien pha trc, sinhvien khong c biet trc nong o

Th nghiem 1:

- Hut 5 ml dung dch mau + 10 ml dung dch chuan EDTA + 3 giot chthBromcresol luc (chnh mau vepH = 5-6 bang cach cho NH4OH vao en khi dungdch comau xanh) + 2ml em pH = 5,5, lam 3 mau trong 3 bnh non 250ml

- un nhekhoang 800C- Them vao 2 ml em pH = 5,5 + 1 giot chthXylenon da cam (lam 3 mau).- Chuan obang dung dch Zn2+ va xac nh c nong otrong th nghiem tren

(chuan nong): dung dch chuyen txanh luc sang hong tm.- Tthetch o c 3 mau, tnh nong odung dch Al3+

Th nghiem 2:

- Hut 5 ml dung dch mau (chnh mau vepH = 5 bang cach cho NH4OH vao) + 5mlem pH = 5,5 + 10 ml dung dch EDTA + 3 giot chthaxi t Sunfosalicilic, lam 3mau trong 3 bnh non 250ml

- Chuan obang dung dch Fe3+ axac nh c nong oth nghiem tren: dungdch chuyen tkhong mau sang nau.

- Tthetch o c 3 mau, tnh nong odung dch Al3+

Cau hoi:

1. So sanh ket quahai qui trnh, nhan xet vaanh gia, giai thch?2. Viet ay ucac phng trnh phan ng trong bai thc tap?3. Giai thch vai trocua tng hoa chat asdung trong bai thc tap?

V. NH LNG HON HP Al3+ + Fe3+:

Dung dch mau ladung dch hon hp Fe3+ + Al3+ (0,01M - 0,05M) c giao vienpha trc, sinh vien khong c biet trc nong o

- Hut 5ml dung dch mau + NH4OH 2N chnh en pH = 2,5 + 1 giot axitSunfosalicilic cho vao erlen, lam 3 mau trong 3 bnh non 250ml

- Chuan obang dung dch EDTA 0,01M cho en khi dung dch chuyen ttm nhosang mat mau. Ghi thetch EDTA tieu ton.

- Tiep tuc cho vao 1 giot Bromcresol luc + NH4OH 2N chnh en pH = 5 + 2 mlem pH= 5,5 + un nhe (800C). Lam nguoi bang nc lanh vathem vai giotXylenon da cam vao erlen

- Chuan obang dung dch Zn2+ axac nh nong otrong th nghiem tren: dungdch chuyen txanh luc sang cam tm. Ghi thetch Zn2+ tieu ton .


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- Tthetch o c 3 mau, tnh nong ocua tng dung dch Fe3+ vaAl3+

Cau hoi:

1. Viet ay ucac phng trnh phan ng trong bai thc tap?2. Giai thch vai trocua tng hoa chat asdung trong bai thc tap?3. V sao phai un soi dung dch phan tch trc khi cho chthXylenon da cam vao?

4. Thiet lap cong thc tnh nong oAl

3+

vaFe

3+

?


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Bai 13: NH LNG HON HP M g2+ + Zn2+ VAHON HP Mg2+ + Ca2+ + Fe3+ + Al3+

I I I. CHUAN B:

- Dung dch em acetat pH =10- Dung dch em acetat pH =5,5- Dung dch EDTA 0.01M- NaOH 2N- NH4OH 2N- HNO3 am ac- NH4Cl 5%- Giay loc bang vang

- Dung dch HCl 1:4- Dung dch Zn2+ 0,01M- ETOO- Murexi t- MR 0,1 %- Sunfosalicilic- Bromcresol luc

IV. NH L NG HON HP Mg2+ + Zn2+:

Dung dch mau lahon hp dung dch Zn2+ + Mg2+ (0,01M - 0,05M) c giao vienpha trc, sinh vien khong c biet trc nong o

Th nghiem 1:

- Hut 10 ml dung dch mau + 10 ml em pH = 10 + 0,01g ETOO cho vao erlen, lam3 mau trong 3 bnh non 250ml

- Chuan obang dung dch chuan EDTA 0,01M: dung dch chuyen tmau onhosang xanh cham. Ghi thetch EDTA tieu ton.

- Cung tien hanh nh tren cho mau trang tng t, ghi thetch EDTA tieu ton.Th nghiem 2:

- Hut 10 ml dung dch mau + 10 ml em pH = 10 vat chthETOO +5 ml KCN20% cho vao erlen, lam 3 mau trong 3 bnh non 250ml

- Chuan obang dung dch chuan EDTA 0,01M: dung dch chuyen tmau onhosang xanh cham cua bnh chng. Ghi thetch EDTA tieu ton.

- Cung tien hanh nh tren cho mau trang tng t, ghi thetch EDTA tieu ton.- Tthetch o c 3 mau va2 th nghiem, tnh nong otng dung dch Zn2+

vaMg2+

Cau hoi:1. Viet ay ucac phng trnh phan ng trong bai thc tap?2. Giai thch vai trocua tng hoa chat asdung trong bai thc tap?3. a ra vachng minh cac cong thc tnh?


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V. NH L NG HON HP Ca2+, Mg2+, Al3+, Fe3+:

Dung dch mau ladung dch hon hp Fe3+ + Al3+ + Ca2+ + Mg2+ (0,01M - 0,05M)c giao vien pha trc, sinh vien khong c biet trc nong oHut 20 ml dung dch mau + 5 giot HNO3 am ac, un nhetrong khoang 2 3 phut, enguoi + 2 giot MR 0,1% (dung dch comau hong) + nhotng giot NH4OH 2N cho enkhi dung dch mau vang (coket tua), comui NH3 bay ra, un cho het NH3 tdo, lam 3

mau trong 3 bnh non 250ml- Loc ket tua bang giay loc bang vang, ra ket tua 5 lan bang NH4Cl 5% nong .

Dch loc vanc ra c gop chung. Goi ladung dch 1- Hoatan ket tua bang HCl 1: 4 nong, thu c dung dch mi, goi ladung dch 2.

Vay: (dung dch 1) em i xac nh Ca2+vaMg2+.(dung dch 2) em i xac nh Al3+ vaFe3+.

1. Dung dch 1: Xac nh Ca2+ vaMg2+

Th nghiem 1:

- Hut 5 ml (dd 1) + 5 ml em pH = 10 + ETOO.- Chuan obang dung dch chuan EDTA 0,01M: dung dch chuyen tmau onho

sang xanh cham. Ghi thetch EDTA tieu ton.- Lam mau trang tng tnhng thay mau bang nc cat. Ghi thetch EDTA tieu

tonTh nghiem 2:

- Hut 5 ml (dd1) + 2 ml NaOH 2N + 0,01g Murexit cho vao erlen- Chuan obang dung dch chuan EDTA 0,01M : dung dch chuyen tmau hong

uc sang tm hoa cacua bnh chng. Ghi thetch EDTA tieu ton .- Lam mau trang tng tnhng thay mau bang nc cat. Ghi thetch EDTA tieu

ton- Tthetch o c 3 mau, tnh nong odung dch Mg2+ vaCa2+.

2. Dung dch 2: Xac nh Al 3+ vaFe3+

- Hut 5ml (dd2) + NH4OH 2N chnh en pH = 2,5 + 3 giot axi t Sunfosalicilic chovao erlen

- Chuan obang dung dch EDTA 0,01M: dung dch chuyen ttm nho sang matmau. Ghi thetch EDTA tieu ton.

- Lam mau trang tng tnhng thay mau bang nc cat. Ghi thetch EDTA tieuton

- Tiep tuc cho vao 1 giot Bromcresol luc + NH4OH 2N chnh en pH = 5 + 2 mlem pH= 5,5 + un nhe (800C). Lam nguoi bang nc lanh +1 giot Xylenon dacam vao erlen

- Chuan obang dung dch Zn2+ axac nh nong otrong th nghiem tren: dungdch chuyen txanh luc sang cam tm. Ghi thetch Zn2+ tieu ton (tien hanh chuanonong).

- Lam mau trang tng tnhng thay mau bang nc cat. Ghi thetch Zn2+ tieu ton- Tthetch o c 3 mau, tnh nong odung dch Fe3+ vaAl3+

Cau hoi:


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1. Viet ay ucac phng trnh phan ng trong bai thc tap?2. Giai thch vai trocua tng hoa chat asdung trong bai thc tap?3. a ra vachng minh cac cong thc tnh?


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Bai 14: NH LNG Ba2+ VASO42

I . CHUAN B:

- Dung dch em pH =10- Dung dch HCl 1:4- BaCl2 0,02N- EDTA 0,01M- Mg2+0,01M

- NH4OH 2N- H2SO4 0,1N- ETOO- MO 0,1%

I I .NH LNG Ba2+:

Dung dch mau ladung dch BaCl 2 (0,01N - 0,05N) c giao vien pha trc, sinh

vien khong c biet trcTh nghiem 1:

- Hut 10 ml dung dch Mg2+ 0,01M (chnh mau vepH = 9 -10 bang cach choNH4OH vao) + 10 ml em pH = 10 vat chthETOO (lam 2 mau). em chuan obang dung dch EDTA 0,01M cho en khi dung dch chuyen tmau onho sangxanh cham. Ghi thetch EDTA tieu ton (V1).

- Hut 5 ml Ba2+ cho vao erlen tren, chuan otiep bang dung dch EDTA 0,01M choen khi dung dch chuyen tmau onho sang xanh cham. Ghi thetch EDTA tieuton (V2).

- Tthetch o c 3 mau, tnh nong odung dch Ba2+

Th nghiem 2:

- Hut 10 ml dung dch EDTA 0,01M (chnh mau vepH = 9 -10 bang cach choNH4OH vao) +10 ml em pH = 10 vat chthETOO (lam 3 mau). em chuan obang dung dch Mg2+ 0,01M cho en khi dung dch chuyen tmau xanh chamsang onho. Ghi thetch Mg2+ tieu ton (V1).

- Hut 5 ml Ba2+ cho vao erlen tren, lac ch5 phut, chuan otiep bang dung dchEDTA 0,01M cho en khi dung dch chuyen tmau onho sang xanh cham. Ghithetch EDTA tieu ton (V2).

- Tthetch o c 3 mau, tnh nong odung dch Ba2+ .

Cau hoi:

1. nh lng Ba2+ bang 2 th nghiem tren coskhac biet g? Th nghiem nao cothecho ket quagan ung hn? Giai thch?

2. Giai thch cac hien tng cotrong 2 th nghiem nay?

I I I . NH LNG SUNFAT BANG PHNG PHAP GIAN TIEP:

Dung dch mau ladung dch Na2SO4 (0,01N - 0,05N) c giao vien pha trc,sinh vien khong c biet trc


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- Hut 10 ml dung dch mau + 10 ml nc cat + 1 giot MO 0,1% + 1 giot HCl 1:4(cho HCl 1:4 en khi dung dch comau hong o), them tiep 2 giot HCl 1:4 na .Lam tng t3 mau trong 3 bnh non 250ml.

- un nong khoang 800C, them tt30mL dung dch BaCl2 0,02N vao, khuay eu,eket tua lang tren bep un cach thuy30 45 phut.

- Loc ket tua bang giay loc bang xanh, dch loc c hng vao bnh non, ra ket tua

bang nc cat cho en het ion Ba2+

(thbang H2SO4 0.1N, khi odung dch comau odau).- Lay dch loc chnh vepH = 9 - 10 bang cach cho tng giot NH4OH 2N vao (th

bang giay pH) luc odung dch comau cam, goi la (dd 1).- Lay 1 erlen khac hut 10 ml EDTA 0,01M + 10 ml em pH = 10 + 0,01g chth

ETOO, lac eu.- Chuan obang Mg2+ 0,02 N cho en khi dung dch chuyen txanh cham sang o

nho, goi la(dd 2)- Hut 10ml (dd 1) cho vao erlen cocha (dd 2). em chuan obang EDTA 0,01M

cho en khi dung dch chuyen tonho sang xanh cham. Ghi thetch EDTA tieu

ton. Lam tng tvi cac mau con lai.- Tthetch o c 3 mau, tnh nong odung dch SO42

Cau hoi:

1. Viet ay ucac phng trnh phan ng trong bai thc tap?2. Giai thch vai trocua tng hoa chat asdung trong bai thc tap?3. a ra vachng minh cac cong thc tnh?


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Phan 4: PHNG PHAP CHUAN OKET TUA

Bai 15: PHNG PHAP MOHR VAVOLHARDNH LNG ION CLO

I . CHUAN B:

- Nitro benzen- NaCl 0,05N- HNO3 am ac- Fe2(SO4)3 5%

- Hotinh bot 1%- Chth K2CrO4 8%- Fluoressein 0.1% trong con

I I .XAC NH NONG OCAC DUNG DCH CHUAN:

Th nghiem 1:

Dung dch mau ladung dch AgNO3 (0,01N - 0,05N) c giao vien pha trc,sinh vien khong c biet trc- Hut 10 ml NaCl 0,05 N + 10 giot chthCromat + khoang 20ml nc cat. Lam 3

mau trong 3 bnh non 250ml- Chuan obang AgNO3 cho en khi tua comau cam nhat.- Tthetch o c 3 mau, tnh lai chnh xac nong odung dch AgNO3Th nghiem 2:

Dung dch mau ladung dch KSCN (0,01N - 0,05N) c giao vien pha trc, sinhvien khong c biet trc.- Hut 10 ml AgNO3 (conong ova c hieu chnh tren) + 3giot HNO3 am ac

+ 5 giot Fe3+, lam 3 mau trong 3 bnh non 250ml- Chuan obang KSCN cho en khi dung dch comau ohung- Tthetch o c 3 mau, tnh nong odung dch KSCN

I I I . NH LNG HAM LNG CUA NACl TRONG MUOI AN CONG NGHIEPTHEO PHNG PHAP MOHR:

Mau lamuoi NaCl cong nghiep dang tinh the:- Can khoang 0.2g mau muoi, chuyen vao coc thuy tinh loai 100ml, dung nc nong

hoa tan, sau oloc can qua giay loc bang xanh, dung nc cat nong ra cho enhet ion Cl (thbang dung dch AgNO3)

- Dch qua loc vanc ra tap trung vao bnh nh mc 100ml, enguoi vadungnc cat nh mc ti vach. Dung pipet lay 3 mau cho vao 3 bnh non loai 250mlmoi bnh 5ml mau + 5 giot chthK2CrO4, lac eu.

- Chuan obang dung dch AgNO3 0.05N (cohesohieu chnh) ti khi dung dchxuat hien ket tua ogach. Ghi thetch Nitrat bac atieu ton. Tnh ham lng %NaCl trong mau ban au.


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Dung dch NaCl can gilai elam th nghiem sau.

IV. NH LNG HAM LNG CUA NACl TRONG MUOI AN CONG NGHIEPTHEO PHNG PHAP VOLHARD:

Dung dch mau ladung dch NaCl (0,01N - 0,05N) c sinh vien alam thngiem tren

Th nghiem 1:- Hut 5 ml mau dung dch muoi an apha tren + 3 giot HNO3 am ac + 10 ml

AgNO3 (ac hieu chnh tren) + 3 giot Fe3+, lac eu, lam 3 mau trong 3 bnh

non 250ml.- Chuan obang KSCN (ac hieu chnh tren) cho en khi dung dch comau

ohung- Tthetch o c 3 mau, tnh ham lng % NaCl cotrong mau muoi.

Th nghiem 2:

- Hut 5 ml mau + 1 giot HNO3 am ac + 10 ml AgNO3 (ac hieu chnh tren)

+ 3giot Fe3++ 2 giot Ni tro benzen, lac eu, lam 3 mau trong 3 bnh non 250ml .- Chuan obang KSCN (ac hieu chnh tren) cho en khi dung dch comau

ohung- Tthetch o c 3 mau, tnh nong odung dch NaCl.

Cau hoi:

1. So sanh ket quatnh toan nong ocua NaCl trong 2 th nghiem tren?2. Giai thch vai troNitroBenzen?

V. NH LNG HAM LNG CUA NACl THEO PHNG PHAP FAJANS:

- Hut 25ml dung dch mau + 5ml Fluoressein, lam 3 mau trong 3 bnh non 250ml.- Chuan obang dd AgNO3 th dung dch coket tua trang AgCl nhuom mau o(khicho AgNO3 vao th dd buc, gan iem tng ng AgCl ket tua dan dan ong tulai luc nay ta phai lac manh khi ket tua nhuom oth dng lai).

- Tthetch o c 3 mau, tnh nong odung dch NaCl.

Cau hoi:

1. So sanh ket qua 3 phng phap Mohr, Volhard, Fajans. Conhan xet g ve3phng phap nay?

2. Viet cac phng trnh phan ng xay ra trong th nghiem, vagiai thch chung?


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CHNG II : PHNG PHAP PHAN TCH KHOI LNG

Bai 16: XAC NH SO42 (hoac Ba2+)

I . CHUAN B:

- Dung dch HCl 1:1- Dung dch AgNO3 0.05N- Dung dch BaCl2 1%- ChthMO 0.1% pha trong nc

I I .NH LNG SUNFAT:

- Nung chen 850oC trong 30 phut, enguoi trong bnh hut am en nhiet ophong,

can chen khong c m0.- Can chnh xac khoang 0,2g Na2SO4 bang can kythuat, hoa tan Na2SO4 vao bnh

nh mc bang nc cat en 100ml.- Hut 10ml mau cho vao 2 coc + 3 giot MO 0,1% mau comau vang + nhotng giot

HCl 1:1 edung dch chuyen tvang sang hong- at coc vao noi, un cach thuy trong 30 phut (khong c phep un soi)- Cho ttBaCl2 1% (en khi khong nhn thay sket tua tren bemat tiep xuc), tiep

tuc un soi tren bep cach thuy.- Sau 30 phut lay coc ra enguoi. em loc bang kythuat loc gan. Dung nc cat

nong trang coc lien tuc cho en khi mau khong con trong coc (phan nc trang o

vao giay ang loc).- Tiep tuc ra ket tua cho en het Cl- (thion Cl - bang dung dch AgNO3)- em ket tua aloc bang giay loc cho vao chen, em tro hoa tren bep ien en khi

giay loc hoa en vahet khoi.- em chen ac tro hoa vao lonung, nung nhiet o850oC trong 30 phut- enguoi trong bnh hut am en nhiet ophong em can lai m1 (g)- Tnh ham lng cua Na2SO4.

Cau hoi:

1. Nguyen nhan gay mat mau?

2. Giai thch quatrnh cho cac chat vao etao tua?3. V sao phai un cach thuytrong 30 phut valai khong c un soi dung dch?


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Bai 17: XAC NH Fe3+

I . CHUAN B:

- Dung dch AgNO3 1%- NH4NO3 5%- Dung dch NH3, HNO3, FeCl3

I I .NH LNG Fe3+:

Ran mau latinh theFeCl 3 coham lng xac nh do giao vien giao, nhng sinhvien khong c biet trc ham lng nay.- Nung chen Ni 9000C trong 30 phut. enguoi trong bnh hut am, roi can chen

khong (m0)- Can chnh xac khoang 0.4 gam FeCl3 mau bang can kythuat, tam t mau bang

5ml HCl ac, hoa tan vanh mc en 250ml bang nc cat.- Lay 25ml mau cho vao chen (lam them mau oi chng) + 2ml HNO3 2N.- un nong khoang 75 - 800C (khong lam soi dung dch) + 30ml dung dch NH3 1N

+ 50ml H2O nong, eyen trong 5 phut.- Thdung dch aket tua hoan toan cha bang cach nho5 giot NH3 1N vao dung

dch, neu dung dch con tua th cho them vao 10ml dung dch NH3 1N- Loc nhanh ngay tc khac bang giay loc bang vang khong tro. Ra tua bang

NH4NO3 0,5N ac un nong. Tiep tuc ra tua bang nc nong eloai trCl-

(thlai bang AgNO3)- Cho tua vao chen nung vatro hoa(lam giay hoaen vakhong con khoi). em

nung 9000C trong 30 phut (khong c nung qualau). enguoi trong bnh hutam en nhiet ophong, can lai (m1)

- Ap dung cong thc tnh khoi lng exac nh ham lng Fe3+.

Cau hoi:

1. Viet ay ucac phng trnh phan ng trong bai thc tap?2. Giai thch vai trocua tng hoa chat asdung trong bai thc tap?3. a ra vachng minh cac cong thc tnh? Giai thch yngha cua cac cong oan

trong qui trnh xac nh?


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Bai 18: XAC NH Mg2+

I . CHUAN B:

- Dung dch HCl 1:1- AgNO3 0.05N- NH3 1:10- NH4NO3 5%

- (NH4)2HPO4 5%- MR 0.1% trong con- Giay loc bang xanh

I I .NH LNG Mg2+:

Ran mau latinh theMgSO4 .7 H2O coham lng xac nh do giao vien giao,nhng sinh vien khong c biet trc ham lng nay.- Nung chen Ni 8500C trong khoang 40 phut. Sau oenguoi 5 phut th em can

(m1)- Can khoang 0.3 0.5 gam MgSO4.7H2O cha biet ham lng, cho vao chen nung

(lam them mot coc elam mau song song), them 3ml HCl 1:1 + 40ml nc cat + 2giot MR 0.1% + 15ml (NH4)2HPO4 5%

- un nhedung dch 40 - 450C + them 2ml NH3 ac (dung dch hoa vang)- enguoi han them tiep 5ml NH3 ac- un cach thuy 30 phut. Tien hanh loc nong qua giay loc bang xanh vi kythuat

loc gan (bang cach dung dung dch NH3 1:10 ra ket tua cho en het ion Cl , thbang AgNO3). Tiep tuc ra ket tua 2 lan, moi lan 5ml NH4NO3 5%.

- Chuyen giay loc cha ket tua vao chen nung, tro hoa chen mau tren bep ien enkhi giay loc chay en vahet khoi, chuyen vao lonung achnh ti nhiet o850oC,nung khoang 40 phut (ti khi ket tua trang), lay ra ebnh hut am 5 phut, can m2

- Totnh c ham lng cua Mg2+ cotrong mau.

Cau hoi:

1. Viet ay ucac phng trnh phan ng trong bai thc tap?2. Giai thch vai trocua tng hoa chat asdung trong bai thc tap?3. a ra vachng minh cac cong thc tnh? Giai thch yngha cua cac cong oan



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375

Bai 19: XAC NH PHOTPHAT

I . CHUAN B:

- Na2HPO4.12H2O, NH4Cl 2N- Hon hp Mg: 14gNH4Cl + 11g MgCl2.6H2O + nc cat nh mc en 100ml, pha

trc esau 1 ngay roi loc mi c sdung- NH3 am ac, NH3 1:10 , NH4NO3 0.05N- Dung dch AgNO3 0.05N- Chth: PP 0.1%- Dung dch thuoc thmagie: 70g NH4Cl + 55g MgCl2.6H2O + nc cat = 1 lt, sau

1 ngay loc mi c sdung.

I I .NH LNG PO43:

- Nung chen niken 850oC trong 40 phut sau oenguoi em can- Can khoang 0.3g Na2HPO4.12H2O coham lng 99% (lam 2 mau coc 1 can c

0.3089g, coc 2 can c 0.3064g). Them 50 ml nc cat vao mau ehoa tan + 5mlNH4Cl 2N + 15ml hon hp Mg + 3giot PP 0.1%

- un khoang 40-45oC + them tt2ml NH3 am ac (cho en khi dung dch hoahong). enguoi han them vao 5ml NH3 am ac.

- Coc 1 un cach thuy 30 phut. Coc 2 eyen 1gi, sau oloc tua qua giay loc bangxanh.oi vi coc1 loc nong bang cach loc gan.

- Sau khi loc het phan nc trong, bat au ra tua bang NH3 1:10 (ehan chethuyphan valam giam otan)

- Sau vai lan ra tua trong coc ta chuyen toan botua vao trong coc roi tiep tuc ratua cho het Cl - (khi uoi het Cl - lacung uoi het cac ion d khac)

- ThCl - bang AgNO3 0.05N (tua khong con Cl- khi nc ra tua khong buc khi

cho AgNO3)- em tro hoa mau tren bep ien sau o em nung 850oC trong 40 phut (cho en

khi tua trang). era ngoai 5 phut roi em can.- Tnh ham lng PO4

3- cotrong mau.

Cau hoi:

1. Viet ay ucac phng trnh phan ng trong bai thc tap?

2. Giai thch vai trocua tng hoa chat asdung trong bai thc tap?3. a ra vachng minh cac cong thc tnh? Giai thch yngha cua cac cong oan



44/44


Chubien : ThS. LeThThanh Hng

Bien soan : Bomon Phan tch

Hieu nh : Trng Bach Chien

Sa ban in : LeThThanh Hng Nguyen ThCam Tu

Xong ngay 1.9.2004 tai khoa Hoa trng Cao ang Cong nghiep 4

[kiemnghiemthucpham.blogspot.com]_thuc hanh phan tich dinh luong

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