Добавил:

fench Опубликованный материал нарушает ваши авторские права? Сообщите нам.

Вуз:

Казанский национальный исследовательский технологический университет

Предмет:

Химия

Файл:

Lange's Handbook of Chemistry (15th Edition) / 63847 8.pdf

Скачиваний:

134

Добавлен:

15.08.2013

Размер:

1.02 Mб

Скачать

☆

1 / 111 2 3 4 5 6 7 8 9 10 11 > Следующая >>>

		SECTION 8
		ELECTROLYTES,
	ELECTROMOTIVE FORCE,
		AND
	CHEMICAL EQUILIBRIUM
8.1	ACTIVITY COEFFICIENTS		8.2
Table 8.1 Individual Activity Coefﬁcients of Ions in Water at 25 C			8.3
Table 8.2 Approximate Effective Ionic Radii in Aqueous Solutions at 25 C			8.4
Table 8.3 Constants of the Debye-Hu¨ ckel Equation from 0 to 100 C			8.5
Table 8.4 Individual Ionic Activity Coefﬁcients at Higher Ionic Strengths at
		25 C	8.5
8.2	EQUILIBRIUM CONSTANTS		8.6
Table 8.5 Ionic Product Constant of Water			8.6
Table 8.6		Solubility Product Constants	8.6
8.2.1	Proton-Transfer Reactions		8.17
Table 8.7 Proton Transfer Reactions of Inorganic Materials in Water at 25 C			8.18
Table 8.8 pKa Values of Organic Materials in Water at 25 C			8.24
Table 8.9 Selected Equilibrium Constants in Aqueous Solution at Various
		Temperatures	8.73
Table 8.10 Properties of Common Acid-Base Solvents			8.80
Table 8.11 pKa Values for Proton-Transfer Reactions in Nonaqueous Solvents			8.81
8.2.2 Formation Constants of Metal Complexes			8.82
Table 8.12 Cumulative Formation Constants for Metal Complexes with
		Inorganic Ligands	8.83
Table 8.13 Cumulative Formation Constants for Metal Complexes with Organic
		Ligands	8.88
8.3	BUFFER SOLUTIONS		8.104
8.3.1 Standard Reference pH Buffer Solutions			8.104
Table 8.14 National Bureau of Standards (U.S.) Reference pH Buffer Solutions			8.105
Table 8.15 Compositions of Standard pH Buffer Solutions [National Bureau of
		Standards (U.S.)]	8.106
8.3.2 Standards for pH Measurement of Blood and Biological Media			8.106
Table 8.16 Composition and pH Values of Buffer Solutions			8.107
Table 8.17 Standard Reference Values pH*s for the Measurement of Acidity in
		50 Weight Percent Methanol-Water	8.109
Table 8.18 pH* Values for Buffer Solutions in Alcohol-Water Solvents at 25 C			8.109
8.3.3 Buffer Solutions Other Than Standards			8.110
Table 8.19 pH Values of Biological and Other Buffers for Control Purposes			8.110
8.4	REFERENCE ELECTRODES		8.113
Table 8.20 Potentials of Reference Electrodes in Volts as a Function of
		Temperature	8.113
Table 8.21 Potentials of Reference Electrodes (in Volts) at 25 C for Water–
		Organic Solvent Mixtures	8.114
8.4.1	Electrometric Measurement of pH		8.115
Table 8.22 Values of 2.3026RT/F at Several Temperatures			8.115
8.5	INDICATORS		8.116
Table 8.23 Indicators for Aqueous Acid-Base Titrations			8.116
Table 8.24		Mixed Indicators	8.118

8.1

8.2		SECTION 8
Table 8.25		Fluorescent Indicators	8.120
Table 8.26 Selected List of Oxidation-Reduction Indicators			8.122
8.6	ELECTRODE POTENTIALS		8.124
Table 8.27 Potentials of the Elements and Their Compounds at 25 C			8.124
Table 8.28 Potentials of Selected Half-Reactions at 25 C			8.137
Table 8.29 Overpotentials for Common Electrode Reactions at 25 C			8.140
Table 8.30 Half-Wave Potentials of Inorganic Materials			8.141
Table 8.31 Half-Wave Potentials (vs. Saturated Calomel Electrode) of Organic
		Compounds at 25 C	8.146
8.7	CONDUCTANCE		8.157
Table 8.32 Limiting Equivalent Ionic Conductances in Aqueous Solutions			8.157
Table 8.33 Standard Solutions for Calibrating Conductivity Vessels			8.160
Table 8.34		Electrical Conductivity of Various Pure Liquids	8.161
Table 8.35		Equivalent Conductivities of Electrolytes in Aqueous Solutions at
		18 C	8.163
Table 8.36		Conductivity of Very Pure Water at Various Temperatures and the
		Equivalent Conductances of Hydrogen and Hydroxyl Ions	8.168
8.7.1	Common Conductance Relations		8.168

8.1

ACTIVITY COEFFICIENTS

Although it is not possible to measure an individual ionic activity coefﬁcient,

fi , it may be estimated

from the following equation of the Debye-Hu

¨ckel theory:

log fi

i2 pI

Ba ˚ pI

where

I is

the ionic

strength of

the

medium,

and

a˚ is the ion-size

parameter— the effective ionic

radius (Table 8.2). The values of

and B

vary with the temperature and dielectric constant of the

solvent; values from 0 to 100

C for aqueous medium (

a˚

in angstrom units) are listed in Table 8.3.

Corresponding

values of

and

for

unit

weight

solvent (when employing molality) can be

obtained by multiplying the corresponding values for unit volume (molarity units) by the square

root of the density of water at the appropriate temperature.

The ionic strength can be estimated from

the

summation

of the product molarity times

ionic

charge

squared

for all

the

ionic

species

present

the

solution,

i.e.,

I 0.5(c 1z 12

c 2z 22 · · · c iz 2i ).

Values for the activity coefﬁcients of ions in water at 25

C are given in Table 8.1 in terms of

their effective ionic radii.

At moderate ionic strengths a considerable improvement is effected by subtracting a term

bI from

the Debye-Hu

¨ckel expression;

is an adjustable parameter which is 0.2 for water at 25

C. Table 8.4

gives the values of the ionic activity coefﬁcients (for

z i from 1 to 6) with

a˚

taken to be 4.6A

In general, the mean ionic activity coefﬁcient is given by

f (x y ) pf x f y

ELECTROLYTES, EMF, AND CHEMICAL EQUILIBRIUM					8.3
TABLE 8.1 Individual Activity Coefﬁcients of Ions in Water at 25			C

		ƒi at Ionic Strength of
Effective Ionic Radii
Effective Ionic Radii
a˚ (in A˚)	0.001	0.005	0.01	0.05	0.1
Univalent Ions
9	0.967	0.933	0.914	0.86	0.83
8	0.966	0.931	0.912	0.85	0.82
7	0.965	0.930	0.909	0.845	0.81
6	0.965	0.929	0.907	0.835	0.80
5	0.964	0.928	0.904	0.83	0.79
4	0.964	0.928	0.902	0.82	0.775
3.5	0.964	0.926	0.900	0.81	0.76
3	0.964	0.925	0.899	0.805	0.755
2.5	0.964	0.924	0.898	0.80	0.75
Divalent Ions
8	0.872	0.755	0.69	0.52	0.45
7	0.872	0.755	0.685	0.50	0.425
6	0.870	0.749	0.675	0.485	0.405
5	0.868	0.744	0.67	0.465	0.38
4.5	0.868	0.741	0.663	0.45	0.36
4	0.867	0.740	0.660	0.445	0.355
Trivalent Ions
6	0.731	0.52	0.415	0.195	0.13
5	0.728	0.51	0.405	0.18	0.115
4	0.725	0.505	0.395	0.16	0.095
Tetravalent Ions
11	0.588	0.35	0.255	0.10	0.065
5	0.57	0.31	0.20	0.048	0.021
Pentavalent Ions
9	0.43	0.18	0.105	0.020	0.009

where f ,f are the individual ionic activity coefﬁcients, and							x ,y are the charge numbers		( zof ,z )
the respective ions. In binary electrolyte solution.
			f p
			f p		f f
In ternary electrolytes, e.g., BaCl	2 or K	2 SO,4
	f p3			or			f 3p
	f p3	f f 2		or			f 3p	f2 f
In quaternary electrolytes, e.g., LaCl	3 or K 3 [Fe(CN)					6 ],
	f p4			or
	f p4	f f 3		or			f p4f3 f

TABLE 8.2

Approximate Effective Ionic Radii in Aqueous Solutions at 25

˚a (in A˚)

Inorganic Ions

˚a (in A˚)

Organic Ions

2.5

, Cs

,NH

3.5

HCOO

, H 2 Cit

,CH NH3

) NH 3 2

Tl , Ag

, (CH3

,NO

3 HN

COOH, (CH

)3 NH

,C H2

NH5

, Cl , Br , I , CN

2, NO

3.5

, F

, SCN

, OCN

4.5

CH3 COO

2 COO

, (CH

3 )4N

,(C H2

) 5NH2

, HS ,ClO

3 , ClO4

, BrO3

, IO4

, MnO4

, ClCH

,Hg

H 2 NCH

2 COO

, oxalate

, HCit

. . . . . . .

Na , CdCl

2, ClO

2, IO3

, HCO

3 , H 2PO 4, HSO

H AsO2

, S2

ClCHCOO2

, Cl3 COO

, (C 2

5)3 NH

,C H3

NH7 , 3

Cit

, succi-

,4SO

4, S O2 3

, SeO4

, CrO4

, HPO4

, S2

Cr(NH

)

3 6

Co(NH

3 )5H

nate

, malonate

, tartrate

4, Fe(CN)

3 ,) 6Co(NH

2 O

4.5

Co(NH

3 )5Cl

, Fe(CN)

5NO

ben zoate

, hydroxybenzoate

, chlorobenzoate

, phenylace-

. . . . . . .

Pb ,CO

, SO3

, MoO4 ,

, Ra

, Cd

, Hg

, Fe(CN)

tate

, vinylacetate

, (CH

3 )2 C

"CHCOO

, (C

2 H

. . . . . . .

Sr, Ba

, S ,S2

, WO4

, Ca

, Cu

, Fe

, Ni

, Co

,Co(en)

(C 3 H

7 )2

2phthalate,

, glutarate

, adipate

. . . . . . Li

, Zn

, Sn , Mn

Co(S O2 3)(CN)

trinitrophenolate

, (C 3

7 )3 NH

, methoxybenzoate

, pime-

8. . . . . . . . . . . . . . .

. . . . . . Mg

2 , Be2

late 2 , suberate

2 , Congo red anion

, Fe

, Cr

, La

, Ce

, Pr

, Nd

(C6 H

5)2 CHCOO

, (C 3

7 )4N

. . . . . . .

H , Al

, Sc

, Y

, In

,Co(SO )3 2(CN)

, Ce

, Zr

, Sn

4.8

	ELECTROLYTES, EMF, AND CHEMICAL EQUILIBRIUM							8.5
TABLE 8.3	Constants of the Debye-Hu	¨ckel Equation from 0 to 100				C
		log ƒi	Az i2	pI
			Az i2	pI

		1	Ba ˚ pI
	Unit Volume of Solvent						Unit Volume of Solvent
Temp.,				Temp.,
Temp.,				Temp.,
C	A	B			C		A	B

0	0.4918	0.3248		55			0.5432	0.3358
5	0.4952	0.3256		60			0.5494	0.3371
10	0.4989	0.3264		65			0.5558	0.3384
15	0.5028	0.3273		70			0.5625	0.3397
20	0.5070	0.3282		75			0.5695	0.3411
25	0.5115	0.3291		80			0.5767	0.3426
30	0.5161	0.3301		85			0.5842	0.3440
35	0.5211	0.3312		90			0.5920	0.3456
40	0.5262	0.3323		95			0.6001	0.3471
45	0.5317	0.3334		100			0.6086	0.3488
50	0.5373	0.3346

The values for unit weight of solvent (molality scale) can be obtained by multiplying the corresponding values for unit volume by the square root of the density of water at the appropriate temperature.

TABLE 8.4 Individual Ionic Activity Coefﬁcients at Higher Ionic Strengths at 25												C
The values were calculated from the modiﬁed Debye-Hu									¨ckel equation utilizing the modiﬁcations proposed by
Robinson and by Guggenheim and Bates:
							log ƒi		0.511 I	0.2 I
								1	1.5 I	0.2 I
							z i2	1	1.5 I
where	I is the ionic strength and				a˚ is assumed to be 4.6 A				˚
where	I is the ionic strength and				a˚ is assumed to be 4.6 A				.

			log 10ƒi							ƒi	for z i
										ƒi	for z i
I
			z i2		1	2			3		4	5		6
					1	2			3		4	5		6

0.05		0.0756			0.840	0.498			0.209		0.0617	0.0129		0.00190
0.1		0.0896			0.814	0.438			0.156		0.0369	0.00576		0.000595
0.2		0.0968			0.800	0.410			0.138		0.0283	0.00380		0.000328
0.3		0.0936			0.806	0.422			0.144		0.0318	0.00457		0.000427
0.4		0.0858			0.821	0.454			0.169		0.0424	0.00716		0.000815
0.5		0.0753			0.841	0.500			0.210		0.0624	0.0131		0.00195
0.6		0.0631		0.865		0.559			0.270	5	0.0978	0.0265		0.00535
0.7		0.0496			0.892	0.633			0.358		0.161	0.0575	5	0.0164
0.8		0.0352			0.922	0.723			0.482		0.273	0.132		0.0541
0.9		0.0201			0.955	0.831			0.659		0.477	0.314		0.189
1.0		0.0044			0.900	0.960			0.913		0.850	0.776		0.694

1 / 111 2 3 4 5 6 7 8 9 10 11 > Следующая >>>

Соседние файлы в папке Lange's Handbook of Chemistry (15th Edition)

#
15.08.2013389.34 Кб12963847 3.pdf
#
15.08.2013493.08 Кб14063847 4.pdf
#
15.08.2013909.2 Кб17663847 5.pdf
#
15.08.2013756.49 Кб12463847 6.pdf
#
15.08.20131.51 Mб12563847 7.pdf
#
15.08.20131.02 Mб13463847 8.pdf
#
15.08.201354.75 Кб12263847 9.pdf
#
15.08.201353.14 Кб11463847 pref.pdf