Solution: When 99.9% of the Cuhas been precipitated,
c(S2?) = K?sp(CuS)/c(Cu2+)
= 6.3?10?36/(0.01?0.1%)
= 6.3?10?31
Qi = c(Cd2+)c(S2?) = 0.01?6.3?10?31 < K?sp(CdS) = 8.0?10?27
Therefor, 100% Cd2+ remains in the solution.
23£® Calculate the molar solubility of each of the following minerals from its K?sp
?10
(1) alabandite, MnS: K?sp=2.5?10
?8
(2) anglesite, PbSO4: K?sp=1.6?10
?11
(3) brucite, Mg(OH)2: K?sp=1.8?10 (4) fluorite, CaF2: K?sp=2.7?10?11
Solution: (1) s = (K?sp)1/2 = (2.5?10?10)1/2 = 1.6? 10?5(mol?L?1)
(2) s = ( K?sp)1/2 = (1.6?10?8)1/2 = 1.3?10?4(mol?L?1)
1/3?111/3?4?1
(3) s = ( K?sp/4) = (1.8?10/4) =1.7?10(mol?L)
(4) s =( K?sp/4)1/3 = (2.7?10?11/4)1/3 = 1.9?10?4(mol?L?1)
24£® Consider the titration of 25.00mL of 0.08230 mol?L?1 KI with 0.05110 mol?L?1 AgNO3.
Calculate pAg at the following volumes of added AgNO3: (1)39.00 mL ; (2) Vsp; (3) 44.30mL ;
Solution: (1) c(I?) = (0.08230?25.00?0.05110?39.00)mol/(25.00+39.00)L
?1
= 0.001009(mol?L) c(Ag+) = K?sp(AgI)/c(I?)
?17
= 8.3?10/0.001009 = 8.2?10?14
+
pAg = ?lg c(Ag) =13.09 +1/2
(2) c(Ag) ={K?sp(AgI)}
?171/2
= (8.3?10)= 9.1?10?9
pAg = 8.04 +
(3) c(Ag) = (0.05110?44.30?0.08230?25.00)/(25.00+44.30)
= 0.002976 pAg = 2.53
2+
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1£®ÇóÏÂÁÐÎïÖÊÖÐÔªËØµÄÑõ»¯Öµ¡£ (1)CrO42?ÖеÄCr (2)MnO42?ÖеÄMn
(3)Na2O2 ÖеÄO (4)H2C2O4?2H2OÖеÄC
½â£º(1)Cr£º+6£»(2) Mn£º+6£» (3) O£º?1£» (4) C£º+3
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(1)Cl2 + H2O = HClO + HCl (2)Cl2 + H2O2 = 2HCl + O2
(3)Cu + 2H2SO4(Ũ) = CuSO4 + SO2 + 2H2O
(4)K2Cr2O7 + 6KI + 14HCl = 2CrCl3 + 3I2 + 7H2O + 8KCl ½â£º (1)Cl£º´Ó 0 ? +1 ºÍ ?1£»
(2)Cl£º´Ó 0 ? ?1£»O£º´Ó ?1 ? 0£» (3)Cu£º´Ó 0 ? +2£»S£º´Ó +6 ? +4£» (4)Cr£º ´Ó+6 ? +3£» I£º´Ó ?1 ? 0¡£
3£®ÓÃÀë×Óµç×Ó·¨Å䯽ÏÂÁÐÔÚ¼îÐÔ½éÖÊÖеķ´Ó¦Ê½¡£
(1)Br2 + OH? ¡ú BrO3? + Br? (2)Zn + ClO? ¡ú Zn(OH)42? + Cl? (3)MnO4? + SO32? ¡ú MnO42? + SO42? (4)H2O2 + Cr(OH)4? ¡ú CrO42? + H2O ½â£º(1) Br2+12OH?=2BrO3?+6H2O+10e?
( 2e? + Br2 = 2Br?) ¡Á 5
?
6Br2 + 12OH= 2BrO3? + 6H2O +10 Br?
?2? ?
(2) Zn + 4OH = Zn(OH)4+ 2e
H2O + ClO? + 2e? = 2OH? + Cl?
?? 2? ?
Zn + H2O + 2OH + ClO= Zn(OH)4+ Cl(3) (MnO4? + e? = MnO42?) ¡Á 2
? 2?
2OH+ SO3= H2O + SO42? + 2e?
2MnO4? + 2OH? + SO32? = 2MnO42? + H2O + SO42? (4) (H2O2 + 2e? = 2OH?) ¡Á3
? ?
(4OH+ Cr(OH)4= CrO42? + 4H2O + 3e?) ¡Á 2
? ? 2?
3H2O2 + 2OH+ 2Cr(OH)4= 2CrO4+ 8H2O
4£®ÓÃÀë×Óµç×Ó·¨Å䯽ÏÂÁÐÔÚËáÐÔ½éÖÊÖеķ´Ó¦Ê½¡£
(1) S2O82? + Mn2+ ¡ú MnO4? + SO42?
(2) PbO2+ HCl ¡ú PbCl2 + Cl2 + H2O (3) Cr2O72? + Fe2+ ¡ú Cr3+ + Fe3+
?
(4) I2+ H2S ¡ú I+ S
½â£º (1) (S2O82? + 2e? = 2SO42?) ¡Á 5
2+ ? + ?
(4H2O + Mn= MnO4+ 8H+ 5e) ¡Á2
2? 2+ ?
5S2O8+ 8H2O + 2Mn= 2MnO4+ 16H+ + 10SO42?
(2) PbO2 + 4H+ + 2e?= Pb2+ + 2H2O
??2Cl=Cl2 +2e
PbO2 + 4HCl = PbCl2 + Cl2 + 2H2O (3) Cr2O72? +14H+ + 6e? = 2Cr3+ + 7H2O
(Fe2+ = Fe3++e?) ¡Á 6
2? +
Cr2O7+ 14H+ 6Fe2+ = 2Cr3+ + 7H2O + 6 Fe3+
? ?
(4) I2 + 2e= 2I
+ ?
H2S = S + 2H+ 2e ? + I2+ H2S = 2I+ S + 2H
5£®Diagram galvanic cells that have the following net reactions.
(1) Fe + Cu2+ = Fe2+ + Cu (2) Ni + Pb2+ = Ni2+ + Pb (3) Cu + 2Ag+ = Cu2+ + 2Ag (4) Sn + 2H+ = Sn2+ + H2 ½â£º(1) (?) Fe | Fe2+¡¬Cu2+ | Cu(+)
2+2+
(2) (?)Ni | Ni¡¬Pb | Pb(+)
2++
(3) (?)Cu| Cu¡¬Ag |Ag(+) (4) (?)Sn| Sn2+¡¬H+ |H2| Pd(+) 6£®ÏÂÁÐÎïÖÊÔÚÒ»¶¨Ìõ¼þ϶¼¿ÉÒÔ×÷ΪÑõ»¯¼Á£ºKMnO4, K2Cr2O7, CuCl2, FeCl3, H2O2, I2, Br2, F2,
PbO2¡£ÊÔ¸ù¾Ý±ê×¼µç¼«µçÊÆµÄÊý¾Ý£¬°ÑËüÃǰ´Ñõ»¯ÄÜÁ¦µÄ´óС˳ÐòÅÅÁУ¬²¢Ð´³öËüÃÇÔÚËáÐÔ½éÖÊÖеĻ¹Ô²úÎï¡£
½â£ºÑõ»¯ÄÜÁ¦ÓÉ´óµ½Ð¡ÅÅÁÐÈçÏ£º
F2 > H2O2 > KMnO4 > PbO2 > K2Cr2O7 > Br2 > FeCl3 > I2 > CuCl2
ÔÚËáÐÔ½éÖÊÖеĻ¹Ô²úÎïÒÀ´ÎΪ£º
F?, H2O, Mn2+, Pb2+, Cr3+, Br?, Fe2+, I?, Cu
7£®Calculate the potential of a cell made with a standard bromine electrode as the anode and a
standard chlorine electrode as the cathode.
Solution: E?(Cl2/Cl?)=1.358V, E?(Br2(l)/Br?) =1.065V
the potential of a cell: E? = E?(+) ? E?(?)=1.358V?1.065V=0.293V
8. Calculate the potential of a cell based on the following reactions at standard conditions.
(1) 2H2S +H2SO3 ¡ú 3S +3H2O (2) 2Br?+2Fe3+¡úBr2 +2Fe2+ (3)Zn +Fe2+¡úFe+Zn2+
(4)2MnO4?+5H2O2+6HCl¡ú2MnCl2 +2KCl+8H2O+5O2
Solution: (1)0.308V; (2)?0.316V; (3)0.323V; (4)0.828V.
?+2+
9£®ÒÑÖª MnO4+8H +5e = Mn+4H2O E?=1.51V
Fe3++e =Fe2+ E?=0.771V
(1)ÅжÏÏÂÁз´Ó¦µÄ·½Ïò
MnO4? + 5Fe2+ + 8H+ ¡ú Mn2+ + 4H2O +5Fe3+
(2)½«ÕâÁ½¸ö°ëµç³Ø×é³ÉÔµç³Ø£¬ÓÃµç³Ø·ûºÅ±íʾ¸ÃÔµç³ØµÄ×é³É£¬±êÃ÷µç³ØµÄÕý¡¢¸º¼«£¬²¢¼ÆËãÆä±ê×¼µç¶¯ÊÆ¡£
(3)µ±ÇâÀë×ÓŨ¶ÈΪ10mol?L?1£¬ÆäËü¸÷Àë×ÓŨ¶È¾ùΪ1mol?L?1ʱ£¬¼ÆËã¸Ãµç³ØµÄµç¶¯ÊÆ¡£ ½â£º(1) MnO4?+5Fe2++8H+¡ú Mn2++4H2O+5Fe3+
E?+ > E?? ·´Ó¦ÕýÏò½øÐÐ (2) (?)Pt| Fe3+(c1), Fe2+(c2)¡¬MnO4?(c3), Mn2+(c4) | Pt£¨+£©
E? =1.51? 0.771= 0.739V
c(Ñõ»¯ÐÍ)0.0592Vlg nc(»¹ÔÐÍ)? E? (3) E = E+? E? = E?++?
80.0592Vlg105= 1.51V + ? 0.771V
= 0.83V
10£®ÒÑÖª Hg2Cl2(s)+2e?=2Hg(l)+2Cl? E? =0.28V Hg22++2e?=2Hg(l) E? =0.80V
ÇóK?sp(Hg2Cl2)¡£ (Ìáʾ£º Hg2Cl2(s) Hg22++2Cl?)
½â£º Hg2Cl2(s) +2e=2Hg(l)+2Cl E?= 0.28V Hg22++2e?=2Hg(l) E? = 0.80V
½«ÉÏÊöÁ½µç¼«·´Ó¦×é³ÉÔµç³Ø£º
(?)Pt|Hg(l)|Hg2Cl2(s)|Cl?¡¬Hg22+|Hg(l)|Pt(+)
µç³Ø·´Ó¦Îª£º Hg22++2Cl?= Hg2Cl2(s) E? = 0.80V ?0.28V = 0.52V
?2?0.52Vn?E? 0.0592V= 17.57 K? =1017.56 ·´Ó¦µÄƽºâ³£Êý lgK= 0.0592V?
??
K?sp(Hg2Cl2) = 1/K?= 1/10 = 2.8?10
11£®ÒÑÖªÏÂÁÐµç³Ø Zn| Zn2+(x mol?L?1)¡¬Ag+(0.10 mol?L?1)|AgµÄµç¶¯ÊÆE =1.51V£¬ÇóZn2+Àë
×ÓµÄŨ¶È¡£
½â£º E = E+? E? = 1.51V
[E(Ag/Ag) + 0.0592Vlgc(Ag)] ?[E(Zn/Zn) +
0.05922?
+
+
?
2+
17.56?18
0.05922Vlgc(Zn2+)] =1.51V
[0.799V+0.0592Vlg0.10] ? [?0.763V +Vlgc(Zn2+)] =1.51V
c(Zn2+) = 0.57(mol?L?1)
12£®ÎªÁ˲ⶨµÄÈܶȻý£¬Éè¼ÆÁËÏÂÁÐÔµç³Ø
(?)Pb| PbSO4| SO42?(1.0 mol?L?1)¡¬Sn2+(1.0 mol?L?1)|Sn(+)
ÔÚ25?Cʱ²âµÃµç³Øµç¶¯ÊÆE?= 0.22V£¬ÇóPbSO4ÈܶȻý³£ÊýK?sp¡£ ½â£º²é±í E?( Sn2+/Sn) = ?0.136V E?(Pb2+/ Pb) = ?0.126V
E?= E?+ ? E?? 0.22V = ?0.136 ? E?? E?? = E?( PbSO4/ Pb)= ?0.356V
2?0.0592lgc(Pb)2+2+??2E(PbSO4/ Pb)= E(Pb/ Pb) = E(Pb/ Pb) +
0.0592?0.356V = ?0.126V +20.0592?0.356V = ?0.126V +2lgc(Pb)
lg K?sp(PbSO4)/c(SO4)
2?
2+
lgK?sp(PbSO4) = ?7.77 K?sp = 1.7?10?8
13£®¼ÆËã298KʱÏÂÁÐµç³ØµÄµç¶¯ÊƼ°µç³Ø·´Ó¦µÄƽºâ³£Êý¡£
(1) (?) Pb | Pb2+(0.1 mol?L?1)¡¬Cu2+(0.5 mol?L?1)|Cu(+)
(2) (?) Sn | Sn2+(0.05 mol?L?1)¡¬H+(1.0 mol?L?1)|H2(105Pa) |Pt(+) (3) (?) Pt | H2(105Pa)|H+(1mol?L?1)¡¬Sn4+(0.5 mol?L?1), Sn2+(0.1 mol?L?1 )|Pt(+) (4) (?) Pt | H2(105Pa)|H+(0.01 mol?L?1)¡¬H+(1.0 mol?L?1)|H2(105Pa) | Pt(+)
0.0592½â£º(1) E+ = 0.337V +2Vlg0.5 =0.33V
0.0592E? = ?0.126V +2Vlg0.1 = ?0.16V
E = E+ ? E? = 0.33V ?(?0.16V) = 0.49V
2?(0.337??0.126)nE ??0.0592V0.0592lgK== 15.64 K? = 4.38¡Á1015
(2) E+ = E?(H+/H2) = 0
E? = ?0.136V +
E = E+ ? E? = 0.17V
0.05922Vlg0.05 = ?0.17V
2?(?0?0.136)nE ?4.594 ?0.0592V0.0592lgK== K?=3.9¡Á10
(3) E+ = 0.151V +
0.05922E? = E?(H+/H2) =0
E = E+ ? E? = 0V ? 0.17V = 0.17V
0.5Vlg0.1= 0.17V