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1 Chapter 12. : ,, (galvanic cell, vltaic cell) (electrlytic cell) 6,, Cu(s) Cu 2+ (aq) + 2e - Ag + (aq) + e - Ag(s) Cu(s) + 2Ag + (aq) Cu 2+ (aq) + 2Ag(s)

2 Cu Cu 2+ Ag + Ag =>. 12.2

3 (electrical ptential difference), ε (cell vltage) (vltameter) : ( ) : ε = ε ε ε ε. ε ε. ε > ε Cu 2+ (aq) + 2Ag(s) Cu(s) + 2Ag + (aq), (electrlytic cell)., Cu Ag Ni(s) Ni 2+ (aq) HCl(aq) H 2 (g) Pt(s) : Ni(s) Ni 2+ (aq) + 2e - : 2H + (aq) + 2e- H 2 (g) Ni(s) + 2H + (aq) Ni 2+ (aq) + H 2 (g) Ni(s) + 2HCl(aq) H 2 (g) + NiCl 2 (aq)

4 --- ( ) (equivalent mass): / e = C 1 Q = ( ml -1 )*( C) = 96, C ml -1 F = 96, C ml -1 Faraday cnstant. (electric current) =, Ampere(A) I = Q / t Q = It = Q / F - Zn(s) Zn 2+ (aq) + 2e - Ag + (aq) + e - Ag(s) 1 Zn(s).5 ml = 65.38/2 = g Zn Ag(s) 1 ml = g Ag CdSO 4 ZnSO 4. (a). (b) 1.45 A 2.6.?? (c). (d).

5 : PV(pressure-vlume) : (electrical wrk) Q ε w = Q ε = It ε J = C*(J/C), J/C = V w <, ε > w >, ε < V A. Q. G = H TS = E+ PV TS G = E+ P V T S ( ) 1 E = q+ w= q+ w P V G = E+ P V T S = q+ w P V + P V T S = q+ w T S q= q = T S G = w,. w = G ( ) n ( nf ), ε, G = w = Q ε = nf ε 7, 9 : 1, : 1M G : - ( D) G = nf ε ε () -(standard cell vltage)

6 Zn Zn 2+ C 2+ C.48V. 1M, 1g 25 C.? (Half-Cell Vltages) ε. Zn Zn 2+ Cu 2+ Cu,, Zn 2+ (aq) + 2e - Zn(s) Cu 2+ (aq) + 2e - Cu(s) ε (reductin ptential) ε (Zn 2+ Zn) ε (Cu 2+ Cu). () = = ( ) ( ) ε = ε ( ) ε ( ) = ε ( Cu Cu) ε ( Zn Zn) = 1.1 V ε ( )!

7 ε (H 3 O + (1M) H 2 ) =., 2 H 3 O + (aq) + 2e - H 2 (g) + 2 H 2 O(l) ε = V (), H 2 (g) 1, H 3 O + (aq) 1M H 3 O + (1M) H 2. Cu 2+ (1M) Cu H 3 O + (1M) H 2, ε = ε ( ) ε ( ) = ε ( Cu Cu) ε ( H O H ) = ε ( Cu Cu) =.34 V, Cu 2+ (1M) + 2e - Cu(s) ε =.34 V 3 2 Zn 2+ (1M) Zn H 3 O + (1M) H 2, ε = ε ( ) ε ( ) = ε ( H O H ) ε ( Zn Zn) = ε ( Zn Zn) =.76 V, Zn 2+ (1M) + 2e - Zn(s) ε = -.76 V 3 2, Zn 2+ (1M) Zn Cu 2+ (1M) Cu,. ε = ε ( ) ε ( ) = ε ( Cu Cu) ε ( Zn Zn) =.34 V (.76 V) = 1.1 V 12.5 ( 12.7, 12.8 ) 14. Pt Fe 2+,Fe 3+ Cd 2+ Cd (a) E. (b).

8 (xidizing agent) : E, O 2 O 3. (reducing agent) : E.,!. Cu 2+ (1M) + 2e - 2+ Cu(s) ε1 = ε ( Cu Cu) =.34 V Cu + (1M) + e - + Cu(s) ε2 = ε ( Cu Cu) =.522 V, Cu 2+ (1M) + e - Cu + (aq) 2+ + ε = ε ( Cu Cu ) ε ε =.182 V G = n Fε. G3 = G1 G2 = nf 1 ε1 + n2fε2 = n3fε3 nf 1 ε1 nf 2 ε 2, ε3 = n (2 ml)(.34 V) (1 ml)(.522 V) ε3 = ε ( Cu Cu ) = =.158 V 1 ml

9 Cu 2+ 2Cu + Cu 2+ + Cu(s) ε = =.364 V ε >, G < C. Tl 3+ + e - Tl 2+ ε =-.37 V Tl e - Tl + ε =1.25 V (a) Tl 2+ + e - Tl +. (b) Tl 2+? 2Tl 2+ (aq) Tl 3+ (aq) + Tl + (aq)

10 12.3,! 9, G = G + RTln Q G = w = Q ε = nf ε G = nf ε, nf ε = nf ε + RT ln Q (Nernst Equatin) RT ε = ε ln Q nf ln Q= lge Q 2.33lg 1 Q 25 C RT RT ε = ε ln Q = ε 2.33 nf nf 1 1 (8.315 JK ml )( K) = ε (2.33) lg 1 1 Q n 96485Cml.592 lg = ε 1 Q (25 C n Ag(s) + Cl 2 (g) 2Ag + (aq) + 2Cl - (aq) Cl 2 (s) 1. Ag + (aq) Cl - (aq).25m.16m 25 C.

11 . G = nf ε 8 G = RTln K RT ln K = nf ε nf ln K = ε RT lg 1 K n.592 V = ε (25 C) 12.5 ( 12.7, 12.8 ) (KMnO 4 ). (II) (Mn 2+ ). MnO - 4 Mn 2+ ε 1.49 V. [Zn 2+ ] = [MnO - 4 ] = [Mn 2+ ] = [H 3 O + ] = 1M Zn 2+ Zn, (a). (b). (c) ε ( 12.5, 12.8 ) 12.5 Zn 2+ Zn MnO - 4 Mn 2+ ph 2., [MnO - 4 ] =.12M, [Mn 2+ ] =.1M, [Zn 2+ ] =.15M, 25 C ε ( 12.5, 12.7 ) C.

12 Pb(s) + 2H 3 O + (aq) Pb 2+ (aq) + H 2 (g) + 2H 2 O(l) (a) ε. (b) PbCl 2 [Cl - ].15 M. ph=, P H 2 =1..22 V. [Pb 2+ ]. (c) PbCl 2 K sp.

13 ph ph Pt H 2, ph., Pt H 2 (1) H 3 O + () H 3 O + (1M) H 2 (1) Pt, H 2 (1) + 2 H 2 O(l) 2 H 3 O + () + 2 e - () 2 H 3 O + (1M) + 2 e - H 2 (1) + 2 H 2 O(l) () 1 Q [ H3O + = ( ), n=2,,.592 V.592 V + 2 ε = ε lg1 Q= lg 1[ H3O ] n 2 + =.592 V lg 1[ H3O ] = (.592 V) ph, ph. H 2. ph. ph ph, (glass electrde), AgCl (, 1M) HCl. [H 3 O + ] ph. (saturated calmel electrde), (Hg 2 Cl 2 (s)) KCl. Ag AgCl Cl - + H 3 O + (1.M) H 3 O + () Cl - () Hg 2 Cl 2 (s) Hg Pt

14 , 2 Ag(s) + 2 Cl - (1. M) 2 AgCl(s) + 2 e - () H 3 O + (1.M) H 3 O + () Hg 2 Cl 2 (s) + 2 e - 2 Hg(l) + 2 Cl - () () ε ( ). ε ( ), H 3 O + 1.M,.,.592 V ε = ε( ) lg 1 = ε( )+(.592 V ) ph ε ε( ) ph=.592 V 1 + [ HO 3 ( )] (in-selective electrde): H 3 O : a single cell (vltaic pile): (battery f cells),.. (primary cells): (secndary cells): (Leclanche cell):, -, 1.5V Zn(s) Zn 2+ (aq) + 2 e - () 2 MnO 2 (s) + 2 NH + 4 (aq) + 2 e - Mn 2 O 3 (s) + 2 NH 3 (aq) + H 2 O(l) () Zn(s) + 2 MnO 2 (s) + 2 NH + 4 (aq) Zn 2+ (aq) + Mn 2 O 3 (s) + 2 NH 3 (aq) + H 2 O(l)

15 (alkaline dry cell):. Zn(s) + 2 OH - (aq) Zn(OH) 2 (s) + 2 e - () 2 MnO 2 (s) + H 2 O(l) + 2 e - Mn 2 O 3 (s) + 2 OH - (aq) () Zn(s) + 2 MnO 2 (s) + H 2 O(l) Zn(OH) 2 (s) + Mn 2 O 3 (s). - (zinc-mercuric xide cell):

16 - (nickel-cadmium cell nicad battery) - (lead-acid strage battery) -

17 (fuel cell) : (),. 2 H 2 (g) + O 2 (g) 2 H 2 O(l) 25 C, 1M, 1 ε ( H2 H2O) =.828 V ε ( O2 OH ) =.41 V ε = ε ( ) ε ( ) = ε ( O2 OH ) ε ( H2 H2O) =.41 V (.828 V) = V OH - ph. CO(g) + O 2 (g) CO 2 (g)

. : w ( ) = G : qp H ( qp = H ),. Th Tl Th Tl w ( ) = ε qp = H G < G Th Th 3-35% 6-7%. 12.5. : (shrt-circuted).

18 . : w ( ) = G : qp H ( qp = H ),. Th Tl Th Tl w ( ) = ε qp = H G < G Th Th 3-35% 6-7% : (shrt-circuted).. Fe(s) Fe 2+ (aq) + 2 e - () 2 H 2 O(l) + 2 e - 2 OH - (aq) + H 2 (g) () Fe(s) + 2 H 2 O(l) Fe 2+ (aq) + 2 OH - (aq) + H 2 (g).,

19 (, passivatin) (sacrificial ande) (extractive metallurgy): (pyrmetallurgy) (electrmetallurgy).

20 12.1 G f <.. (smelting). 1 C(s) + O 2 (g) CO 2 (g) G = 394 kj ml G f. :, - :

21 (electrrefining). : AgCN. 1.5 A cm g cm -3.

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untitled Chapter 4 Reactions in Aqueous Solution 3 4.1 Pb(NO 3 ) 2 (aq) + 2KI (aq) HCl (aq) + NaOH (aq) Alka-Selter/Water Cu wire/ag(no 3 ) (aq) 3 4.2 (Solution) KMnO 4 (s) K + (aq)+ MnO 4- (aq) 3 4.3 (Molarity)