Examples of determination of substance equivalent for acid-base reactions

Reaction equation	Substance equivalent     1/zX	Equivalence factor	Molar mass of the equivalent
H3PO4+2KOH = K2HPO4+2H2O “X”  two eq.	½H3PO4 (half)	1/2	M(1/2H3PO4)= =1/2M(H3PO4)= =1/2^.98 = 49g/mol
H3PO4+3KOH=K3PO4+3H2O “X”  three eq.	1/3 H3PO4	1/3	M(1/3H3PO4)= =1/3M(H3PO4)= =1/3^.98=32,67 g/mol
Al2(SO4)3+4KOH=[Al(OH)2]2SO4+ + K2SO4 “X”   four eq.	¼ Al2(SO4)3	1/4	M(1/4AL2(SO4)3)= 1/4^.342=85,5 g/mol
2Mg(OH)2+H2SO4=(MgOH)2SO4 + + 2H2O  two eq	1 Mg(OH)2	1	M(Mg(OH)2)= =58 g/mol

 

 

                                                                                                                 

 

Appendix

                                                                                                                    Table 3

Correlation between different concentration units

 

Concentration unit, symbol, dimension	Recalculation formula
Molarity, C(X), mol/l	10ρ(s-n)^.ω%(X) / M(X)
	C(1/zX) / z
	b(X)^.m(s-nt) / V(s-n)
Molar concentration of equivalent (normality), C(1/zX) or N(X), mol/l	10ρ(s-n)^.ω%(X) / M(1/zX)
	Z^.C(X)
	1000^.t(X) / M(1/zX)
Titre, t(X), g/ml	C(1/zX)^.M(1/zX) / 1000
Molality b(X) or Cm(X), mol/kg of the solvent.	C(X)^.V(s-n) / m(s-nt)

 

 

                                                                                                                   

 

Appendix

                                                                                                                 Table 4

 

Examples of determination of equivalent factor and molar mass of equivalent for ox-red reactions

 

Reaction equation	substance equivalent	Ё	Molar mass of equivalent
I2+5Cl2+12KOH=2KIO3+10KCl+6H2O I2+5Cl2+12OH^−=2IO3^−+10Cl^−+6H2O   I2+12OH^−-10e^-=2IO3^−+6H2O  1 “X”    ten eq. Cl2+2e^- = 2Cl^−                      5 “X” two eq.	1/10 I2       ½ Cl2	1/10   1/2	M(1/10 I2)= =1/10^.254= =25,4 g/mol   M(1/2 Cl2)= =1/2^.71= =35,5g/mol
Cr2(SO4)3+3H2O2+10KOH= =2K2CrO4+K2SO4+8H2O 2Cr^3++3H2O2+10OH^-=2CrO4^2-+4H2O   2Cr^3++8OH^−−6e- = 2CrO4^2−+4H2O 1 “X”         six eq. H2O2+2e^- = 2OH^-3 “X” two eq.	1/6 Cr2(SO4)   ½ H2O2	1/6     1/2	M(1/6Cr2(SO4)3) =1/6^.392= =65,33 g/mol   M(1/2H2O2)= =1/2^.34= =17 g/mol

 

Appendix

Table 5

Solubility product of some slightly soluble substances

(25⁰C, * - 18-20⁰C)

substance	SP	substance	SP	substance	SP
AgBr AgCN Ag2CO3 AgCl AgI AgCNS AgOH Ag3PO4* Ag2S Ag2SO4 Ag2CrO4 Ai(OH)3 BaCO3 BaC2O4* BaCrO4 BaF2 BaSO4 Ba3(PO4)2 BaSO3 BaS2O3 Be(OH)2 Bi(OH)3 Bi2S3 CaCO3 CaC2O4 CaF2 Ca(OH)2 CaSO4 Ca3(PO4)2 CdCO3 Cd(OH)2 CdS CoCO3 Co(OH)2 CoS*	7,7^.10^-13 2,0^.10^-12 6,2^.10^-12 1,6^.10^-10 1^.10^-16 1^.10^-13 2^.10^-8 1,8^.10^-18 1^.10^-51 7,7^.10^-5 4^.10^-12 1,9^.10^-33 8^.10^-9 1,7^.10^-7 2,3^.10^-10 1,7^.10^-6 1,1^.10^-10 6,03^.10^-39 8^.10^-7 1,6^.10^-5 6,3^.10^-22 4,3^.10^-31 1,6^.10^-72 4,8^.10^-9 2,6.10^-9 4^.10^-11 3,1^.10^-5 6,1^.10^-5 1^.10^-29 2.5^.10^-14 1,2^.10^-14 1^.10^-29 1^.10^-12 2^.10^-16 2^.10^-27	Cr(OH)3 CuBr CuCO3 CuCl CuI Cu(OH)2 Cu2S CuS (CuOH)2CO3 FeCO3* Fe(OH)2 Fe(OH)3 FeS GeS Hg2Br2 Hg2CO3 Hg2CL2 Hg2I2 Hg2S HgS* K2PtCl6 La(OH)3 Li2CO3 MgCO3  MgF2 MgC2O4* MgNH4PO4 Mg3(PO4)2 Mg(OH)2 MnCO3 Mn(OH)2^* MnS* Na3AlF6 NiCO3 Ni(OH)2	1^.10^-30 5,3^.10^-9 1,4^.10^-10 1,8^.10^-7 1,1^.10^-12 5,6^.10^-20 2,5^.10^-50 4^.10^-38 1,7^.10^-34 2,5^.10^-11 4,8^.10^-16 4^.10^-38 4^.10^-19 3^.10^-35 5^.10^-23 9^.10^-17 2^.10^-18 4^.10^-29 1^.10^-45 4^.10^-58 5^.10^-5 1^.10^-20 1,7^.10^-3 1^.10^-5 6^.10^-9 8,6^.10^-5 2,5^.10^-13 1^.10^-13 5^.10^-12 1^.10^-10 4^.10^-14 1,4^.10^-15 4,1^.10^-10 1,4^.10^-7 7^.10^-14	NiS* PbBr2 PbCO3 PbCl2 PbCrO4 PbF2 PbI2 Pb(OH)2 PbS PbSO4 Pd(OH)2 PtBr4 PtCl4 PtS Sb(OH)2  Sb2S3 Sn(OH)2 Sn(OH)4 SnS SrCO3 SrC2O4* SrF2 SrSO4 Th(OH)4 Ti(OH)3  TlBr TlCl Tl(OH)3 Tl2SO4 Tl2S ZnCO3 Zn(OH)2  ZnS* Zn(CN)2	1,4^.10^-24 7,4^.10^-6 1,5^.10^-13 1,7^.10^-5 1,8^.10^-14 3,7^.10^-8 8,7^.10^-9 2^.10^-16 1^.10^-29 2^.10^-8 1^.10^-24 3^.10^-41 8^.10^-29 8^.10^-43 4^.10^-42 1,6^.10^-93 5^.10^-26 1^.10^-56 1^.10^-28 1^.10^-9 5,6^.10^-8 3,4^.10^-9 2,8^.10^-7 1^.10^-50 1^.10^-40 4^.10^-6 2^.10^-4 1^.10^-44 4^.10^-3 5^.10^-21 6^.10^-11 5^.10^-17 8^.10^-26 2,6^.10^-13.

                                                                                          

                                                                                                                        

 

Appendix

                                                                                                                  Table 6

                  The logariphm table for pH calculations

 

Numbers	0	1	2	3	4	5	6	7	8	9
1	000	041	079	114	146	176	204	230	255	279
2	301	322	342	362	380	389	415	431	447	462
3	477	491	505	519	532	544	556	568	580	591
4	602	613	623	634	644	653	663	672	681	690
5	699	708	716	724	732	740	748	756	763	771
6	778	785	792	799	806	813	820	826	833	839
7	845	851	857	863	869	875	881	887	892	898
8	903	909	914	919	924	929	935	940	945	949
9	954	959	964	968	973	978	982	987	991	996

 

Examples of pH calculation if [H⁺] is known:

 

[H⁺] = 5,3^.10^-1mol/l; pH = -lg[H⁺] = -lg 5,3^.10^-1 = -(0,724 – 1) = -(-0,276) ≈ ≈0,28;

[H⁺]= 5,3^.10^-4mol/l; pH = - lg [H⁺] = -lg 5,3^.10^-4 = -(0,724 – 4) = -(-3,276)≈ ≈ 3,28;

 

Examples of [H⁺] calculation, using pH value:

 

pH = 0,42; [H⁺] = antilg (-0,42) = antilg (0,580 – 1) = 3,8^.10^-1mol/l;

pH = 3,42; [H⁺] = antilg (-pH) = antilg (-3,42) = antilg (0,580 – 4) =

= 3,8^.10^-4mol/l.

 

                                                                                                          

 

 

Appendix

                               

                                                                                                            Table 7

Multiples, symbols of some designations

 

multiply	prefix	symbol	multiply	prefix	Sumbol
10^12 10^9 10^6 10^3 10^2 10	tera- giga- mega- kilo- hecto- deca-	T G M k h da	10^-1 10^-2 10^-3 10^-6 10^-9 10^-12	deci- santi- milli- micro- nano- pico-	D s m μ n p

 

Literature

 

1. Glinka N.L. General chemistry. – L.; Chemistry, 1986. –703 p.

2. Glinka N.L. Tasks and exercises on general chemistry. – L.: Chemistry, 1983. – 264 p.

3. Lenski A.S. Introduction into bioinorganic and biophysical chemistry. – M.: Highest school, 1989. –256 p.

4. Pusacov S.A. Chemistry. – M.: Medicine, 1995. – 624 p.

5. Achmetov N.S. General and inorganic chemistry. – M.: Highest school, 1981. – 679 p.

6. Romanseva L.M., Leshinskaya Z.L., Suchanova V.A. Tasks and exercises on general chemistry. – M.: Highest school, 1991. –288 p.

 

Contents

 

	page
Class 1. Topic: Concentration units.	3
Laboratory work: «Preparation of solution with given concentration by dilution of concentrated solution»	10
Class 2.Topic: Solutions of strong and weak electrolytes	11
Class 3.Topic: Autoprotolysis of water. Ion product of water. Hydrogen and hydroxyl ion exponents. Salt hydrolysis.	16
Class 4. Topic: Buffer solutions. Heterogeneous equilibrium	21
Laboratory work. Heterogeneous equilibrium	27
Class 5. Topic: Colligative properties of nonelectrolyte solutions	29
Class 6. Topic: The summary on the topic: Valumetric analyses	33
Class 7.Topic: The elements of chemical thermodynamics and bioenergetics Termochemistry	34
Class 8.Topic: Chemical kinetics and catalysis	40
Laboratory work. Work 1. Dependence of the reaction rate on the concentrations of reactants	45
Laboratory work. Work 2. Dependence of reaction rate on the temperature	47
Laboratory work. Work 3. Dependence of reaction rate on catalyst concentration	47
Class 9.Topic: chemical equilibrium	48
Laboratory work. Work 1. Shift of the chemical equilibrium, when the reactants     concentrations are changing	53
Laboratory work. Work 2. Shift of the chemical equilibrium if the temperature is changing	54
Laboratory work. Work 3. Reversibility of chemical equilibrium shift	54
Examination questions	55
Appendix	58
Literature	65