CHNG VIII: PHNG PHP CHUN OXI HA KH
CHNG VIII: PHNG PHP CHUN OXI HA KH
Bi 1.
Chun dung dch FeSO4 0,02M bng dung dch K2Cr2O7 0,03M pH = 0. Tnh
th ca in cc Pt trong dung dch cn chun nu sai s chun q = - 0,1%.
Li gii
Phn ng chun :
Khi q = - 0,1% = 10-3 => Trc im tng ng.
Bi 89.
Chun 100ml dung dch FeSO4 0,02M v Fe2(SO4)3 0,03M bng dung dch
Ce(SO4)2 0,04M pH = 0. Tnh th in cc Pt trong dung dch cn chun sau
khi thm: a. 49ml; b. 50ml; c. 51ml dung dch Ce(SO4)2 .
Cho v 300C.
Li gii
Phn ng chun ( 300C):
Theo QTL:
a.V = 49ml => Trc T
Vy:
b. V = 50ml => Ti T
c. V = 51ml. Sau T.
Bi 2
. Chun 50ml SnCl2 0,01M bng FeCl3 trong dung dch HCl.
1. Tnh th ti cc thi im chun sau khi thm: 9ml; 10ml; 10,5ml
FeCl3.
2. Tnh sai s chun nu kt thc chun ti E = 0,35V.
Li gii
Phn ng chun :
1.Theo QTL:
a. V = 9ml. Trc T
b. V = 10ml. Ti T.
c. V = 10,5ml. Sau T.
2.Khi dng chun ti E = 0,35 > ET = 0,32=> ti thi im sau tng
ng.
Bi 3
Chun 100ml dung dch Fe2+ 0,15N bng KMnO4 0,15N pH = 0.
Tnh th ti cc thi im chun sau khi thm: 99,6ml v 100,4ml dung dch
KMnO4.
Li gii
Chun :
1. Phn ng chun :
Theo QTL:
a.V = 99,6ml. Trc T.
b. V = 100,4ml. Ti sau T.
Bi 4
. Chun 25ml Fe2(SO4)3 0,02M bng TiCl3 0,02M pH=0.
1. Tnh bc nhy chun nu coi sai s .
2. Tnh [Fe3+] ti T.
3. Tnh th tch TiCl3 dng lm i mu r cht ch th metilen xanh ( E =
0,33V) v tnh sai s chun . Cho
Li gii
Phn ng chun :
1.Tnh bc nhy chun .
* Ti q = - 0,1% = -10-3. im trc tng ng.
* Ti q = 0,1% = 10-3. Sau T.
2. Phn ng C:
C K>> nn xy ra phn ng nghch.
Ti T, theo QTL ta c: 2C0.V0 = C.V => V= 50ml
C0
C[ ]
=>
Gi s ti T:
=> Ti T nng [Fe3+]
3. Ti T
Ta c:
Ecm< ET => Trc T
Bi 5
Tnh th ti T ca php chun dung dch FeSO4 0,02M bng Br2 0,02M pH =
0.
Li gii
Phn ng C:
K = 106,525
Ti T:
Thnh phn dung dch ti T:
Gi s xy ra cn bng nghch.
n0 C0.V0 2.C.V
n[ ]
Gi s ti T, coi:
( vi C0.V0 = 2.C.V theo QTL)
Thay vo (*) ta c:
Vy:
Bi 6
Feroin c dng lm ch th trong php chun FeSO4 bng dung dch
Ce(SO4)2. Phng trnh phn ng nh sau:
Xanh nht
Tnh sai s chun nu chun dung dch FeSO4 0,02M bng dung dch
Ce(SO4)2 0,04M n chuyn mu cht ch th t sang xanh r.
300C.
Li gii
Phn ng chun :
Ti T:
Phn ng chuyn mu:
Xanh nht
Ecm > ET => Tnh sai s q ti im sau tng ng.
ES = Ecm = ECe + 0,06.lgq
=> 1,09 = 1,44 + 0,06.lgq
=> q = 1,17.10-6 = 1,17.10-4%
Bi 7:
Chun 20,00 ml dung dch urani (IV) 0,1000 M bng dung dch Ce(SO4)2
0,1000 M pH = 0. Phng trnh chun xy ra:
1) Tnh th ti im tng ng ca php chun .
2) Tnh nng ion U4+ ti im tng ng.
3) Tnh th tch dung dch Ce(SO4)2 phi cho vo dung dch cn chun sao
cho th in cc plantin trong dung dch l 0,378V.
4) Tnh th in cc plantin trong dung dch cn chun sau khi thm 50,00
ml Ce(SO4)2 .
5) Tnh sut in ng ca pin:
Hg | Hg2Cl2,KCl bo ho dung dch cn chunti im tng ng | Pt.
Cho .
Li gii
Theo quy tc ng lng : S ng lng U4+ = S ng ca Ce4+
20.0,1=0,1.v
v= 20 ml
1).Tnh th ti im tng ng:
Ta c:
2). Tnh [U4+] ti T:
V k>> nn ta c cn bng ti im tng ng:
k = 10-10,169
nbd c.v c0.v0
[] 2x x
Ta c ti T:
Vy [U4+]=2,91.10-7 (M)
3). th in cc E=0,378(V).Trc im tng ng:
4).Sau khi thm 50 ml Ce(SO4)2 Sau T:
5).Tnh S ca pin ti T :
EMBED Equation.DSMT4
EMBED Equation.DSMT4
EMBED Equation.DSMT4
_1459284426.unknown
_1459284461.unknown
_1459284481.unknown
_1459284498.unknown
_1459284507.unknown
_1459284511.unknown
_1459284513.unknown
_1459284515.unknown
_1459284516.unknown
_1459284518.unknown
_1459284514.unknown
_1459284512.unknown
_1459284509.unknown
_1459284510.unknown
_1459284508.unknown
_1459284502.unknown
_1459284505.unknown
_1459284506.unknown
_1459284504.unknown
_1459284500.unknown
_1459284501.unknown
_1459284499.unknown
_1459284490.unknown
_1459284494.unknown
_1459284496.unknown
_1459284497.unknown
_1459284495.unknown
_1459284492.unknown
_1459284493.unknown
_1459284491.unknown
_1459284486.unknown
_1459284488.unknown
_1459284489.unknown
_1459284487.unknown
_1459284483.unknown
_1459284484.unknown
_1459284482.unknown
_1459284470.unknown
_1459284476.unknown
_1459284479.unknown
_1459284480.unknown
_1459284477.unknown
_1459284478.unknown
_1459284472.unknown
_1459284473.unknown
_1459284475.unknown
_1459284471.unknown
_1459284465.unknown
_1459284468.unknown
_1459284469.unknown
_1459284467.unknown
_1459284463.unknown
_1459284464.unknown
_1459284462.unknown
_1459284444.unknown
_1459284453.unknown
_1459284457.unknown
_1459284459.unknown
_1459284460.unknown
_1459284458.unknown
_1459284455.unknown
_1459284456.unknown
_1459284454.unknown
_1459284448.unknown
_1459284451.unknown
_1459284452.unknown
_1459284450.unknown
_1459284446.unknown
_1459284447.unknown
_1459284445.unknown
_1459284434.unknown
_1459284440.unknown
_1459284442.unknown
_1459284443.unknown
_1459284441.unknown
_1459284436.unknown
_1459284437.unknown
_1459284439.unknown
_1459284435.unknown
_1459284430.unknown
_1459284432.unknown
_1459284433.unknown
_1459284431.unknown
_1459284428.unknown
_1459284429.unknown
_1459284427.unknown
_1459284408.unknown
_1459284417.unknown
_1459284421.unknown
_1459284423.unknown
_1459284424.unknown
_1459284422.unknown
_1459284419.unknown
_1459284420.unknown
_1459284418.unknown
_1459284413.unknown
_1459284415.unknown
_1459284416.unknown
_1459284414.unknown
_1459284410.unknown
_1459284411.unknown
_1459284409.unknown
_1459284399.unknown
_1459284404.unknown
_1459284406.unknown
_1459284407.unknown
_1459284405.unknown
_1459284402.unknown
_1459284403.unknown
_1459284401.unknown
_1459284395.unknown
_1459284397.unknown
_1459284398.unknown
_1459284396.unknown
_1459284393.unknown
_1459284394.unknown
_1459284392.unknown
