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25/01/2015
1
GV: TS MAI TH HI H
Chng 1
DUNG DCH CC CHT IN LY :
CU TRC & TNH CHT
Thnh phn ca dung dch in ly
Cht tan : hp cht lin kt ion/cng ha tr c cc
Dung mi : hp cht phn cc
Cht tan phn ly mt phn/hon ton thnh ion vi in ly
Cc ht trong dd in ly gm :
ion cht tan, phn t cht tan cha b phn ly, phn t dung mi
25-Jan-15 TS. MTH H 2
+ _ _ +
Lc tng tc tnh in Coulomb : ion-ion, ion-dung mi, dung mi-dung mi
Cc phn t u mang in tch
25/01/2015
2
Cu trc ca dung dch in ly
Lc tng tc tnh in Coulomb gia cc tiu phn lm cho :
Cc ion phn b c trt t (khng chuyn ng t do nh trng thi kh).
Chuyn ng ca cc ion u chu nh hng bi in trng ca cc ion khc
xung quanh.
Mi ion c bao quanh bi mt s phn t dung mi : s solvat ha
Khi cc ion gn nhau (trong dung dch nng ln) : c s lin hp ion
(c tha nhn bng pp ph cng hng t ht nhn/electron)
25-Jan-15 TS. MTH H 3
Tng tc ion dung mi : s solvat ha
25-Jan-15 TS. MTH H 4
Phn t H2O gn ion lin kt
tnh in cht vi ion
Lp v hydrat s cp
H2O trong lp v hidrat mt kh
nng quay
Hng s in mi ca nc
gim mnh khu vc gn ion
25/01/2015
3
Tng tc ion ion : s lin hp ion
Khi nng ion ln : cc cation v anion
tng tc tnh in mnh to thnh cp 2, 3
hay nhiu hn ion : C+A-C+, A-C+C+A-.
S to cp ion xy ra d dng hn trong dung
mi c hng s in mi thp (
25/01/2015
4
Mu dd in ly - Thuyt Debye Huckel (1923)
Cc tiu phn trong dd in ly c phn b :
c trt t do lc tng tc tnh in gia chng
hn lon do chuyn ng nhit
M hnh bu kh quyn ion :
Mi ion l 1 trung tm, c bao quanh bi 1 kh quyn gm cc ion tch
in tri du vi s lng nhiu hn ion cng du.
25-Jan-15 TS. MTH H 7
Chn ion dng bt k lm trung tm : in tch zke
ko : in th to bi ion trung tm
a : in th ca bu kh quyn ion
k : in th ti mt im cch ion trung tm khong r
k = ko + a
25-Jan-15
Mu dd in ly - Thuyt Debye Huckel
*Gi thit : Dd long c th :
B qua kch thc ion Th nng tnh in ziek
25/01/2015
5
Mu dd in ly - Thuyt Debye Huckel
25-Jan-15 TS. MTH H 9
2 = -
in th ti mt im mt in tch ti im theo pt Poisson :
: ton t Laplace
: hng s in mi ca dung dch
Nghim tng qut ca pt vi phn :
k1, k2 : hng s tch phn, c xc nh da vo cc iu kin bin :
r , th k 0 : k2 = 0
r 0, th k k ko : in th gy bi ion trung tm =
zke
4r
er k1 = zke
4 =
zke
4
Thuyt Debye Huckel
25-Jan-15 TS. MTH H 10
a (r0) = - Zie
.1/
LD = -1 c coi l bn knh hiu dng ca bu kh quyn ion
in th k ti mt im cch ion trung tm khong r :
Lc ion I :
Dung mi nc 25oC :
(h SI)
(I: mol/dm3, LD : nm)
k = ko + a
ci : nng th tch
25/01/2015
6
1. Tm lc ion ca dung dch:
a. cha Na2SO4 0,08 mol v Cr2(SO4)3 0,02 mol trong 1000 g nc.
b. cha MgSO4 0,01 mol, NaCl 0,005 mol v MgCl2 0,001 mol trong 1000 g
nc.
2. Tm kch thc hiu dng ca lp kh quyn ion 25oC trong dung dch cht
in ly 1-1 c nng 0,1M. Cho hng s in mi ca nc bng 78,6.
25-Jan-15 TS. MTH H 11
Hot - H s hot
25-Jan-15 TS. MTH H 12
Ha th ca ion k trong dd l tng : k,id = o
k,id + RTlnck
Cc phng trnh m t h l tng c th c dng cho h thc t bng
cch thay nng c bng hot a.
Ha th ca ion k trong dd thc : k = o
k + RTlnak
Lin h gia hot & nng : ak = k . Ck
k : h s hot
Hot & h s hot thang nng : mol/L, molan, lg/L
Dd long ca CL yu : a C : 1
Mc lch ca h khi trng thi l tng lch ca khi gi tr 1
25/01/2015
7
Hot & H s hot trung bnh
M+A- + MZ+ + - A
Z-
Nng molan : m m+ =+ m m- = -m
Hot /H s hot : a / a+ / + a- / -
a = m a+ = + m+ a- = -m-
Hot /H s hot trung bnh ca cc ion : a /
Ha th : =o + RTlna + =o
+ + RTlna+ -= o
- + RTlna-
Ha th ca cht tan = ha th cc ion
= + + + - - RTlna = + RTlna+ + - RTlna- (o
= + o
+ + - o
-) a = a++ a-
-
Hot ca cht in ly : a = a++ a-
- = a = + + -
Hot trung bnh ca cc ion : a = (a++ a-
-) 1/ = a1/
25-Jan-15 TS. MTH H 13
Hot & H s hot trung bnh
Hot trung bnh ca cc ion :
a = (a++ a-
-) 1/
a = [(+ m+)+( - m- )
-]1/ = (++-
-) 1/ (m+ +m-
-)1/
H s hot trung bnh ca ion :
= (++-
-) 1/
Nng trung bnh ca ion :
m = (m+ +m-
-)1/ = [(+m)+(-m)
-]1/
= (+ +-
-)1/ m
= Pm vi P = (+ +-
-)1/
a = m = Pm
25-Jan-15 TS. MTH H 14
CL 1-1 : NaCl 1-2, 2-1 : K2SO4 , CaCl2 1-3 : AlCl3 2-3 : Ca3(PO4)2
P = 1 P =
25/01/2015
8
3. Dung dch Ca(NO3)2 nng molan 0,2 c h s hot ion trung
bnh l 0,426. Tm nng ion trung bnh, hot ion trung bnh v
hot ca mui.
4. Xc nh hot v hot trung bnh ca ZnSO4 trong dung dch
0,1 m nu = 0,148.
25-Jan-15 TS. MTH H 15
25-Jan-15 TS. MTH H
+
+ _
_ +
+
_ _
nng C
+ _
dd l tng
dd thc
G
Gid
trng thi chun
H s hot
Ha th ca ion k trong dd thc : k = o
k + RTlnck + RTlnk
k o
k = RTlnck + RTlnk
k = k,id + RTlnk = k,id + kE
Phn hiu chnh do tnh cht thc
k
k,id
GE = G - Gid
kE
nng C trng thi chun
25/01/2015
9
25-Jan-15 TS. MTH H 17
+
+
_
_ +
+
_ _
nng c (dd thc) : Trng thi chun (1 mol/dm3)
long v cng (dd l tng)
Cng phng in W1
Khng c cng in
Cng tch in W2
k
zke
Cng phng in ca 1 ion W1
in th ti khong cch r :
Cng Wk
+ _
H s hot theo thuyt Debye Huckel
k
25-Jan-15 TS. MTH H 18
Cng tch in ca 1 ion W2 :
Cng in tng Wk cho ion k :
Cng in tng Wel cho tt c cc ion trong th tch dung dch V :
S ion Ni = s mol ni . NA
H s hot theo thuyt Debye Huckel
25/01/2015
10
25-Jan-15
TS. MTH H
19
Gi s th tch V khng ph thuc ni, tc coi ion
nh cht im, khng c kch thc
log k = Azk
Nghim ng cho cht in ly 1+-1- c lc ion di 10-2 mol/dm3
Nc 25oC :
H s hot theo thuyt Debye Huckel
log = 0,509z+
nh lut gii hn Debye-Huckel (Pt gn ng bc 1)
H s hot theo thuyt Debye Huckel
Pt gn ng bc 2 ca D-H : C tnh n kch thc ring ca ion
Cc ion ch n gn nhau mt khong gn nht l a (tnh t tm ion)
25-Jan-15 TS. MTH H 20
a : ng knh hiu dng ca ion, a 0,3-0,5 nm
25/01/2015
11
H s hot theo thuyt Debye Huckel
Pt gn ng bc 2 ca D-H :
25-Jan-15 TS. MTH H 21
B = (8e2N)1/2
(103kT)1/2
lg = - |Z+.Z-|A
1 + a.B
Pt bc 2 nghim ng cho dd nng long 0,01 - 0,1 mol/lt, CL 1+-1-
ToC A B
0 88,15 0,488 0,325.108
15 82,23 0,5 0,328.108
25 78,54 0,509 0,330.108
30 78,76 0,514 0,331.108
40 73,35 0,524 0,333.108
50 70,1 0,535 0,335.108
Dd nc to phng :
B = 0,330.108 a.B = 1
lg = - |Z+.Z-|A
1 +
a 3-4.10-8 cm
A, B hng s in mi, nhit .
a : ng knh hiu dng ca ion
Vi nc 25oC :
a 0,3-0,5 nm Ba = 1
H s hot theo thuyt Debye Huckel
Pt gn ng bc 3 ca D-H :
Khi dung dch c nng CL cao (lc ion c th t n n v) : > 1
dd c : s y gia cc ion chim u th hn so vi s ht gia cc ion
s tng hot so vi nng , lm cho > 1
25-Jan-15 TS. MTH H 22
lg
= - Az+z-
1 + Ba
+ CI Vi C : hng s kinh nghim
Lu :
S ht gia cc ion s gim hot so vi nng
S y gia cc ion s tng hot so vi nng
25/01/2015
12
Lin h h s hot ion - nng NaCl/H2O
25-Jan-15 TS. MTH H 23
Quy lut thc nghim :
khi nng (mol/L) tng, qua mt cc tiu
Gii thch :
* Dd long (lc ht gia cc ion >> lc y)
khi
tng, lc ht tng gim
* Dd c (lc ht gia cc ion
25/01/2015
13
5. Dung dch nc ca BaCl2 0,002 m 298 K. Da vo nh lut gii hn ca
D-H, tm h s hot ca ion trong dd v h s hot trung bnh ca ion.
6. Hy tnh h s hot ca ion CrO42- v hot trung bnh ca Ag2CrO4
trong dd nc 25oC khi ha tan 8.10-5 mol/L (in ly hon ton) v c thm
cc cht in ly khc sao cho lc ion bng 0,01.
7. tan ca Tali iodat TlIO3 trong nc c cha KCl 25oC cho trong bng.
a. Tm tch s tan ca TlIO3
b. H s hot ion trung bnh KCl 0,02 mol/lt
c. Hng s A trong pt gii hn ca D-H
25-Jan-15 TS. MTH H 25
[KCl] mol/lt 0.005 0.01 0.02 0.05
S mol/lt 0.00193 0.00200 0.00210 0.00232
Acid, baz, mui phn ly thnh ion khi ha tan trong nc :
M+A- + MZ+ + - A
Z-
Ban u ck in ly ck c+ = ck+ c- = ck- Sau p cn = ck ck c+ = ck+ c- = ck-
ck : nng ban u (mol/th tch)
j : ion j sinh ra do s in ly cht k ban u
cj : nng th tch ca ion j (thng dng mol/cm3)
: in ly ca cht in ly
k : tng s ion do 1 phn t ban u in ly ra : k = - + +
zk : s in tch ca cht in ly : zk = + z+ = -z
-
Dung dch trung ha in nn : (+) cjzj = () cjzj
25-Jan-15 TS. MTH H 27
c : nng tng cng ca tt c cc cht tan trong dung dch : c = cn + c+ + c- = [1 + (k 1)]ck
dn in ca dung dch in ly
25/01/2015
14
dn in ca dung dch in ly
25-Jan-15 TS. MTH H 28
Tc chuyn ng ca ion vj :
Mi ion j s mang in tch zjF (tnh trn 1 mol ion).
Di in trng E (V/cm) : ion j in di vi tc trung bnh vj
vj ph thuc :
- lc ko ca in trng p vo : fj = zjFE
- lc hm do nht ca dung dch : f= (6r) vj = vj
Gi tr vj t c khi 2 lc ny cn bng nhau : zjFE = vj
1
vj = zjFE
Linh (tc tuyt i) ca ion uj
1
uj = zjF (cm2/V.s)
vj E
= zjF
6r Hay uj =
- : nht ca dd
-r : bn knh hiu dng ion
(c bao gm lp hydrat)
uj = tc ca ion di in trng 1 V/cm
8. ng thy tinh cha dung dch NaCl c gn 2 in cc cch nhau 1,53 cm.
Th 12 V c p vo 2 in cc. Sau 5 pht, Na di chuyn c 1,2 cm.
Tm tc tuyt i ca ion.
9. Cho linh ca ion Li+ l 4.10-4 cm2/Vs. Tm thi gian ion dch chuyn t
in cc ny sang in cc kia nu hiu th 10 V c t vo 2 in cc
cch nhau 1 cm.
25-Jan-15 TS. MTH H 29
25/01/2015
15
dn in ca dung dch in ly
Mt dng ion Jj :
Jj = s mol ion j in di qua 1 n v tit din trong 1 n v thi gian
Ion j c nng th tch cj (mol/cm3) & tc chuyn ng vj (cm/s)
Trong 1 v thi gian, ion j i c vj cm
tt c cc ion nm trong th tch vj s i qua 1 v tit din :
Mt dng in ti bi ion j :
Mt dng in : ij = JjzjF = zjFcjujE
Mt dng tng : i = ij = FEzjcjuj
Mt dng in trng, in tch, linh v nng th tch ca tt c
cc ion.
25-Jan-15 TS. MTH H 30
Jj = s mol ion trong th tch vj = cj vj = cjujE
dn in ca dung dch in ly
Mt dng in theo nh lut Ohm :
i t l vi cng in trng :
i = E
bn cht vt liu, nhit
kch thc v dng hnh hc vt liu
25-Jan-15 TS. MTH H 31
dn in ring (S.cm-1) :
l dn ca khi dung dch 1 cm3 t gia 2 in cc din tch 1 cm2, cch
nhau 1 cm
l mt dng in in trng 1 V/cm
= 1
R ()
L (cm)
S (cm2) =
K(cm-1)
R () 1
= S (siemens) = -1
i : mt dng (A/cm2)
: dn in ring (S/cm)
E : cng in trng (V/cm)
: in tr sut
R : in tr
K : hng s bnh (cm-1)
25/01/2015
16
dn in ca dung dch in ly
dn in ring ca dung dch (S.cm-1) :
Mt dng : i = FEzjcjuj
dn in ring ca dung dch = mt dng in in trng 1 V/cm
25-Jan-15 TS. MTH H 32
in tch, nng & linh u ca tt c cc loi ion.
= Fzjcjuj
dn in ring ca dd cht tan nng ban u ck & in ly :
= F (z+c+u+ + z-c-u-) = F [z+(ck+)u+ + z-(ck- )u-]
= F ck ( z++u+ + z--u-) = Fzkck (u+ + u-)
dn in ring ca tng ion : j = Fzjcjuj
dn in ca dung dch in ly
25-Jan-15 TS. MTH H 33
dn in ng lng (S.cm2/lg) : dn ca khi dung dch cha 1
ng lng gam cht lg = M(g/mol)/Z (in ha tr)
S lg = m/(M/Z )= s mol. Z
C (lg/L) = C (mol/L) . Z
= .1000
C (lg/L)
= .1000
C (mol/L) = . Z
= F(u+ + u-) = ( + + -) ng lng ca cht trong p ha tan :
= Mj/zj hay Mk/zk s lg = z.s mol
dn in mol ca dung dch :
dn in mol (S.cm2/mol) : l dn ca khi dung dch cha 1 mol cht
dn in mol ca ion j :
= Fzk (u+ + u-) =
ck (mol/cm3)
= F( z++u+ + z--u-) = ( ++ + --)
j = Fzjuj = j
cj (mol/cm3)
j = Fuj = j
cj (lg/cm3)
25/01/2015
17
dn in gii hn ca dung dch in ly
25-Jan-15 TS. MTH H 34
j = Fuj j, uj : linh ion
= (+ + -)
pha long v cng C 0 : = 1
Linh ca cht in ly v ca cc ion j t gi tr ln nht, gi l gi tr
gii hn hay u
L Kohlrausch 2 : = + + -
Khi dd v cng long, cc ion chuyn ng c lp vi nhau, nn dn in
ng lng gii hn (linh ) ca cht in ly bng tng dn in
ng lng gii hn (linh ) ca cc ion.
Theo Arrhenius : CL yu : Khi C 0 th = 1 : =
=
Bng gi tr dn & linh ion gii hn
25-Jan-15 TS. MTH H 35
Cc gi tr c ngoi suy n long v cng.
25/01/2015
18
dn in gii hn ca dung dch in ly
25-Jan-15 TS. MTH H 36
H+ (aq), OH- (aq) : Linh rt ln so vi cc ion khc.
Theo c ch Grotthus : s nhy ca H+ thng qua phn t H2O
O H
H
H +
O H
H
O
H
O
H
H O
H
H -
Tm tt cc loi dn in
j = Fzjcjuj = Fzkck (u+ + u-) = + + -
j = Fzjuj = Fzk (u+ + u-) = ( ++ + --)
j = Fuj = F (u+ + u-) = ( + + -)
= + + -
= /
25-Jan-15 TS. MTH H 37
25/01/2015
19
10. in tr ca dd KNO3 0,01N c o bng 423 trong bnh o c hng s
bnh l 0,5 cm-1. Tm dn in ring, ng lng, in ly biu kin nu
linh gii hn ca ion K+ v NO3- l 64,5 v 61,6 -1.cm2.lg-1 .
11. Hy tnh dn in gii hn ( dn in v cng long) ca AgIO3
298K bit dn in ng lng gii hn ca NaIO3, CH3COONa, CH3COOAg
298K ln lt l 9,11; 9,10; 10,28 cm2/ohm.lg
12. Tm cho
25-Jan-15 TS. MTH H 38
[KCl] mol/L 0.0005 0.001 0.002 0.005 0.01
(-1.cm2.lg-1) 25oC
124.50 123.74 122.70 120.65 118.51
S ph thuc linh ion ( dn ng lng) - nng
S ph thuc ca dn in ng lng
vo (nng cht in ly)1/2 :
* Cht in ly mnh :
C tng : gim lc u gim nhanh, sau gim chm.
Dd long CL mnh : pt thc nghim Kohlrausch 1 :
= A
A : hng s kinh nghim; C = lg/L
* Cht in ly yu :
C tng : gim lc u gim rt nhanh,
sau gim chm
25-Jan-15 TS. MTH H 39
Ph thuc dn in
ng lng nng
ng lng : - c1/2
25/01/2015
20
S ph thuc linh ion ( dn ng lng) - nng
S gim ca linh ion theo s tng ln ca nng l do s tn ti ca kh
quyn ion :
Hiu ng in di
Hiu ng bt i xng
Ion chuyn ng kh quyn ion tr nn bt i xng vi mt pha sau
ion ln hn : to nn in trng nh ngc chiu vi in trng ngoi
km hm chuyn ng
25-Jan-15 TS. MTH H 40
Di in trng :
Ion v kh quyn chuyn ng ngc chiu
(do in tch tri du)
lc ma st lm gim tc
Ion Kh quyn
V hydrat V hydrat
Nng tng mt ca kh quyn tng cc h cng ln linh ion gim
S ph thuc dn in ring vo nng
25-Jan-15 TS. MTH H 41
* Dd cht in ly mnh (=1) :
ck tng : s lng ion tng, linh ion gim
s tng ca theo ck tr nn chm hn
* Dd cht in ly yu :
ck tng : linh gim + in ly gim
s tng ca theo ck cng tr nn rt
chm so vi TH CL mnh.
* Trong 1 s trng hp, th dn
nng i qua 1 cc i.
Lin h dn in ring 25oC
vi nng (dung mi nc) :
(1) H2SO4; (2) KOH;
(3) NH4Cl; (4) NaNO3
25/01/2015
21
o dn in bng cu Wheatstone
25-Jan-15 TS. MTH H 42
S : ngun in dng xoay chiu nh, tn s ln
R1 : in tr bnh cha dung dch cn o
R2 : in tr bit trc
BD : dy dn c t s in tr ca 2 on dy
BC, CD bng t s chiu di L1 v L2
C : con chy, dch chuyn v tr trn dy
thay i ln in tr ng vi L1 v L2
A
Cu cn bng : dng i qua G = 0
R1
R2 =
L1
L2
I1R1 = I2.L1
I1R2 = I2.L2 B
C D
S
= K(cm-1)
R1 ()
Hng s bnh K : xc nh nh
dung dch in ly chun (KCl)
bit dn in ring
25-Jan-15 TS. MTH H 43
13. Bnh o dn in c chun bi dung dch KCl 0,02 N c dn
in ring l 0,002768 ohm-1.cm-1. in tr o c 25oC l 457,3 ohm.
Bnh c s dng o in tr ca 1 lt dung dch cha 0,555 g CaCl2 vi
gi tr o c l 1050 ohm. Tm hng s bnh, dn in ring v ng
lng ca dung dch CaCl2 .
25/01/2015
22
ng dng ca php o dn in
Tm tan ca mui t tan :
Dung dch bo ha mui c :
tan S (lg/L) & dn in (S/cm)
S rt nh dd long : =
25-Jan-15 TS. MTH H 44
= . 1000
S (lg/L) S =
.1000
.1000
14. 25oC, ngi ta o c dn in ring ca dung dch AgCl bo ha
v ca nc l 2,68.10-6 v 0,86.10-6 -1.cm-1. Tm tan ca AgCl trong nc
25oC. Cho dn in ng lng gii hn ca dung dch AgNO3, HCl v
HNO3 25oC ln lt l 133; 426; 421 -1.lg-1.cm2
25-Jan-15 TS. MTH H 45
Chun axit mnh (HCl) : bng kim (NaOH)
im a : H+, Cl-
Thm NaOH : H+ gim, Na+ c linh km H+
im b : im tng ng : HCl p ht : Na+, Cl-
Thm NaOH : thm ion Na+, OH-
dn in th tch NaOH
a
b c
b
VNaOH
H+
ng dng ca php o dn in
25/01/2015
23
S vn ti
25-Jan-15 TS. MTH H 46
S vn ti ca ion j = phn in lng ti bi ion j :
t+ + t- = 1 t+= i+ i
= u+
u+ + u- =
+
+ + -
Dung dch c 1 cht in ly :
t- = i- i
= u-
u+ + u- =
-
+ + -
tj = ij i
= zjcjuj
zjcjuj
15. Linh ca H+, Cl- v Na+ trong nc 25oC ln lt l 3,623.10-3; 7,91.10-4
v 5,19.10-4 cm2/Vs.
a. Tnh s ti ca H+ trong dung dch HCl 10-3 M.
b. Thm NaCl vo dung dch trn to nng NaCl 1 M (nng HCl xem nh
khng i). Tnh s ti ca H+
Xc nh s vn ti - Phng php Hittorf
25-Jan-15 TS. MTH H 47
Cho 1 Faraday in lng i qua dung dch th :
1 ng lng cht c gii phng trn mi in cc (do p in cc)
t+ : phn in lng ti bi H+
t- : phn in lng ti bi Cl-
1H+ : 1 lg H+ do gii phng trn cathode
+ t+ H+ : t+ lg H+ chuyn n t anode
t- Cl- : t- lg Cl- chuyn i sang anode
(1 t+)H+ t- Cl
- = t- H+ t- Cl- = t- HCl
(1 t-)Cl- t+ H
+ = t+ Cl- t+ H+ = t+ HCl
S lg gim khu cathode :
Bin i lng cht khu cathode :
S lg gim khu anode :
Cathode (-) Anode (+)
1H+ + e H2
+ t+ H+
t- Cl-
1Cl- e Cl2
t+ H+
+ t- Cl-
Khu anode Khu cathode
25/01/2015
24
Xc nh s vn ti - Phng php Hittorf
25-Jan-15 TS. MTH H 48
na nc
= t+ t-
S ng lng cht c gii phng trn mi in cc (p in cc)
S lg gim khu cathode :
q F
n =
q F
nc = t-
S lg gim khu anode :
q F
na = t+
na
na + nc t+ =
Ca
Ca + Cc =
nc
na + nc t- =
Cc
Ca + Cc =
(Nu th tch dd 2 khu nh nhau :
Va = Vc = V)
1 Faraday in lng S lg gim khu cathode t- HCl
q in lng s lg gim khu cathode nc
16. in phn vi in cc graphit dung dch CuCl2 26,9 g/L. Khi kt thc trong
0,5 l dd khu anode c 4,75 g Cu v 0,5 l dd khu cathode c 3,95 g Cu. Tm tCu2+ v
tCl-
Cathode (-) : Cu2+ + 2e Cu -1Cu + t+Cu t-Cl = -t-CuCl2
Anode (+) : Cl- - e1/2 Cl2 -1Cl + t-Cl t+Cu = -t+CuCl2
25-Jan-15 TS. MTH H 49
mCuCl2 trong 0,5l = 26,9:2 =13,45g
mCuCl2/anode = 4,75/63,54.134,54=10,0576g
mCuCl2/cathode = 3,95/63,54.134,54=8,3637g
mc=5,0863 g
ma=3,3924 g
t+ = 0,3972
25/01/2015
25
25-Jan-15 TS. MTH H 52
17. in phn dd AgNO3 vi in cc bng Ag. Trong khu anode, lng AgNO3
trc v sau in phn l 0,2278 g v 0,2818 g. C 0,0194 g Cu bm vo cathode
ca coulomb k Cu mc ni tip bnh in phn. Tm s ti ca Ag+ v NO3-
Anode (+) : Ag-eAg+ : +1Ag+ - t+Ag+ + t-NO3 = + t-AgNO3
Ti anode ha tan : tng t- lg AgNO3
q = 0,0194/(MCu = 63,54) *2 = 0,0006106 mol electron = = 0,0006106 F
S lg AgNO3 tng anode = (0,2818-0,2278)/170=0,0003176
t- = 0,0003176 F/ 0,0006106 F = 0,52
Xc nh s vn ti - Pp ranh gii di ng
25-Jan-15 TS. MTH H 53
+
_
MA
MA
a b
a' b' uM
uM
h
Dd MA tip xc vi dd MA ti v tr ab, tit din tip xc S.
ab : ng ngn cch gia 2 dung dch
Linh ion M > M
Cho in lng q=It qua h :
Cation di chuyn v cc m vi tc M > M
mng ab chuyn n v tr ab
S lg M+ chuyn t ab n ab : C (lg/th tch)Sh
Phn in lng ti bi Mz+ :
zFC(lg/th tch)Sh
q t+ =
25/01/2015
26
18. Trong ng hnh tr ng knh 8 mm, ngi ta 2 dung dch HCl 0,01
M v NaCl sao cho gia 2 dung dch c 1 ranh gii r rt. Khi cho dng in
5 mA i qua th ranh gii di chuyn vi tc 0,085 mm/giy. Tm s ti ca
ion H+.
25-Jan-15 TS. MTH H 54
zFC(lg/L)Sh
q t+ =
Z=1
F=96500
C=0,01 lg/L
S=3,14.0,042dm2
h=0,085.10-2 dm
q=5 mA.1s=5.10-3 A
t+=0,824
19. dn in mol gii hn 25oC ca dung dch nc ca NaI, NaCH3COO, Mg(CH3COO)2 ln lt l : 126,9;
91,0; 187,8 S.cm2/mol. Tm dn in mol gii hn 25oC ca MgI2.
20. Hng s phn ly Kc ca axit C3H7COOH l 1,54.10-5. Tm phn ly ca axit ny pha long V=1/C= 1024
lt/mol. Nu dn in mol gii hn ca dd axit l 350 S.cm2/mol, tm dn in mol ca dung dch axit
pha long trn.
21. Hy tnh phn ly v tch s ion ca nc 25C, bit dn in ring ca nc tinh khit 25oC bng
5,5.10-8 om-1.cm-1. dn in ng lng gii hn ca cc ion H+, OH- l 349,8 v 198,0 cm2/lg.om. Khi
lng ring ca nc 1g/mL.
22. 25oC dn in ng lng gii hn ca NaCH3COO l 91 -1.cm2.lg-1. S ti ca anion l 0,43. dn
in ng lng gii hn ca KCl l 149,8 -1.cm2.lg-1 . S ti ca K+ l 0,49. Tm dn in ng lng
gii hn ca KCH3COO.
23. 25oC dn in ring ca dung dch BaCl2 0,02N l 0,002382 -1.cm-1. S ti ca Ba2+ trong dung dch ny
l 0,4375. Tm tc tuyt i ca ion Ba2+ v Cl-.
24. Cho dng in cng 5,21 mA chy qua ng ng dung dch KCl 0,1 M trong 67 pht, ranh gii dch
chuyn c 4,64 cm. ng c tit din 0,23 cm2. Tm s ti ca K+ v Cl-.
25. Trong ng hnh tr ng knh 8 mm 2 dung dch HCl 0,01 M v NaCl sao cho gia 2 dung dch c 1 ranh
gii r rt. Khi cho dng in 5 mA i qua th ranh gii di chuyn vi tc 0,085 mm/giy. Tm s ti ion H+.
26. Dung dch cht in ly mnh AB c in phn trong bnh Hittorf vi dng 0,1 A trong 9650 giy. P trn
cc in cc AA+ + e v A+ + e A. Dung dch c nng ban u 0,1 mol AB trong 1 kg nc. Sau in phn
trong khu vc anode dung dch gm 100 g H2O v 0,0165 mol AB. Tm s vn chuyn ca ion A+.
27. in phn dung dch cha 14,055 g AgNO3 trong 1000 g nc bng cc in cc Ag. Khi kt thc c 0,1020 g
bc thot ra trn cathode, khu anode c 0,4109 g bc trong 40 g nc. Tm s ti ca ion bc v nitrat.
25-Jan-15 TS. MTH H 55
25/01/2015
27
Hng dn gii BT 5. J=0,006, lg+ = -0,509.2
2.0,0061/2 , + = 0,695
lg = |Z+ . Z-|A
= - 2.[1/2(0,002.4 + 0,004.1) ] 1/2.0,509
= 0,834
6. lg- = -0.509.4.0,1=-0,2036 -=0,625
lg = -0.509.1.2.0,1=-0,1018 =0,791
a = P.m. = 41/3 . 8.10-5.0.791=10-4 ionmol/L
7. T= aTl+aIO3-= [Tl+].[IO3
-].Tl+. IO3-=S2 .
2
lgT = 2lg + 2lgS
Pt gn ng bc 1 : lg = -A
lgT = -2A
+ 2lgS
lgS = A
+ 1/2lgT
y = x + 1/2lgT
x = 0 y = 1/2lgT = -2,7594
T = 3,028.10-6
25-Jan-15 TS. MTH H 56
y = 0.547x - 2.7594
-2.72
-2.71
-2.7
-2.69
-2.68
-2.67
-2.66
-2.65
-2.64
-2.63
0 0.05 0.1 0.15 0.2 0.25
lgS
Sqrt(I)
[KCl] 0.005 0.01 0.02 0.05
S 0.00193 0.002 0.0021 0.00232
I 0.00693 0.012 0.0221 0.05232
sqrtI 0.083247 0.109545 0.148661 0.228736
lgS -2.71444 -2.69897 -2.67778 -2.63451
8. v=1,2/300=0,004 cm/s
u=v/E=0,004/(12/1,53)=5,1.e-4
10. =K/R=0,5/423
= /(0,01.10-3) lg/cm3
12. C = 0 = = 126.4
19. MgI2=Mg(CH3COO)2 2NaCH3COO + 2NaI = 259,6
20. Kc=2/V(1- ) = 0,1179
= / = 41,3
TS. MTH H 57
y = -77.231x + 126.18 R = 0.9996
118
119
120
121
122
123
124
125
0 0.02 0.04 0.06 0.08 0.1 0.12
d
n
in
n
g l
ng
C1/2
25/01/2015
28
21. [H2O] = 1/18/1mL = 0,055 mol/mL = 0,055 lg/cm3
=5,5.10-8/0,055=10-6 = 349,8+198=547,8 = / =1,82.10-9 Kw=[H
+][OH-]= 2C2=10-14
22. t- = - / - = 0,43.91 =39,1
23. = 0,002382.1000/0,02=119,1 -1.cm2.lg-1
t+ = +/ + = 0,4375.119,1= 52,106 -1.cm2.lg-1
u+ = +/F = 5,4.10-4 -1.cm2.lg-1/A.s2 = cm2/s.Volt (Ampe=Volt/ )
24. q=5,21mA.67phut=5,21.10-3.67.60 giy =
t+ = 4,64 cm . 0,23cm2 .10-3. 0,1mol/dm3. F / q = 0,4917
25. t+ = (0,085mm..42mm2. 10-6)0,01mol/dm3 .F/ 5mA.10-3.1 giy=0,824
26. Anode : +1A t+A + t-B = t-AB
S lg tng anode = 0,0165 - 0,01=0,0065 lg t- = 0,0065/(0,1.9650/96500)= 0,65 t+=0,35
27. Anode (+) : Ag Ag+ + e 1Ag -t+Ag +t-NO3 = +t-AgNO3
Cathode (-) : Ag+ + e Ag -1Ag +t+Ag -t-NO3 = -t-AgNO3
B : 0,5622 g AgNO3/40g nc = 3,307.10-3 mol Ag/40g nc
Sau p anode : 3,805.10-3 mol Ag/40g nc
q= 0,1020/108 mol e = F. 0,1020/108
1 F thm t- lg AgNO3 hay t- mol AgNO3
q F thm (3,805-3,307).10-3 mol
t- = 0,527
TS. MTH H 58