Chapter 7 Electrochemistry 87. 3 Applications of Conductivity Measurement
Chapter 7 Electrochemistry §7.3 Applications of Conductivity Measurement
87.3 Applications of Conductivity Measurement 1. Monitor the purity of water Fabrication of VLsI Silicon wafer Ba百科 Integrated circuit
1. Monitor the purity of water Silicon wafer Integrated circuit Fabrication of VLSI §7.3 Applications of Conductivity Measurement
87.3 Applications of Conductivity Measurement 1. Monitor the purity of water Fabrication of VLSI Silicon wafe 图虫创
1. Monitor the purity of water Fabrication of VLSI §7.3 Applications of Conductivity Measurement Silicon wafer
87.3 Applications of Conductivity Measurement 1. Monitor the purity of water Fabrication of VLSI In-situ monitoring of the cleaning water Tap Distilled Deionized Pure process:H2O2/H2SO4→ DW rinse→ water water water water dilute hF→SC-1 cleaning→Dw κsm11×102-1×103 dilute FF→ DW rinse 第12卷第1期 化学进展 Vol 12NO I 2000年2月 PRO GRESS N CHEM ISTRY Feb.1999 DW--deionized water 超大规模集成电路硅片溶液清洗技术的进展 SC-standard cleaning: 张树永郭永榔 (山东大学化学学院济南250100 SC-1: H./NH: SC-2: H,O/HCI 曹宝成于新好
In-situ monitoring of the cleaning process: H2O2 /H2SO4 → DW rinse → dilute HF → SC-1 cleaning → DW rinse → hot DW rinse → DW rinse → SC-2 cleaning → DW rinse → dilute HF → DW rinse. DW⎯deionized water, SC ⎯ standard cleaning： SC-1: H2O2 /NH3 ; SC-2: H2O2 /HCl. 1. Monitor the purity of water Fabrication of VLSI water Tap water Distilled water Deionized water Pure water /S·m-1 1 10-2 ~1 10-3 <1 10-4 5.478 10-6 §7.3 Applications of Conductivity Measurement
87.3 Applications of Conductivity Measurement 2. Measure the ioniza bility and dissociation constant a B a+ B C 0 c(1-a) c a M=C,,F(U+ +U)C+=ac A=a(u+UF Arrhenius suggested that the degree of At infinite dilution dissociation of an electrolyte can be m=F(U+ +U-) calculated using molar conductivity Am-a(U+ +U)F (++U)F
2. Measure the ionizability and dissociation constant m c Z F U U ( ) c + + + − + = c+ =c m = + ( ) U U F + − At infinite dilution m F U U ( ) = + + − m m ( ) ( ) U U F U U F + − + − + = = + Arrhenius suggested that the degree of dissociation of an electrolyte can be calculated using molar conductivity. §7.3 Applications of Conductivity Measurement
87.3 Applications of Conductivity Measurement 2. Measure the ioniza bility and dissociation constant Ostwald showed how one can measure the dissociation constant of an acid 007 C C K C (1-a)c1-aA(1n-n Ostwald dilution law 0.03 The equation can be rearranged to 001 C)+ A K Linearization
2 2 2 2 m m m m (1 ) 1 ( ) c c c K c = = = − − − Ostwald dilution law Ostwald showed how one can measure the dissociation constant of an acid. The equation can be rearranged to 2 m m m m 1 1 1 ( ) a c K = + Linearization 2. Measure the ionizability and dissociation constant §7.3 Applications of Conductivity Measurement
87.3 Applications of Conductivity Measurement 3. Determine solubility and solubility products Example: The conductivity of a saturated K=c.n++c C Ag Ag OH OH AgCl solution is 1.86 10+S", while K一K=C,++Cr=S(++1-) that of water used for preparation the solution is 6.0x 10-6S. m-I Given that the molar conductivity of AgCl is 0.01372 .,+2 S- m2. Calculate the solubility product for AgCI What assumption have we made?
3. Determine solubility and solubility products - Ag Ag Cl Cl H H OH OH = + + + c c c c + + − + + − − w Ag Ag Cl Cl Ag Cl − = + = + c c S + + − − + − ( ) w w Ag Cl m S + − − − = = + Example: The conductivity of a saturated AgCl solution is 1.86 10-4 S·m-1 , while that of water used for preparation the solution is 6.0 10-6 S·m-1 . Given that the molar conductivity of AgCl is 0.01372 S·mol-1·m2 . Calculate the solubility product for AgCl. What assumption have we made? §7.3 Applications of Conductivity Measurement
87.3 Applications of Conductivity Measurement 4. Determine ion product of water The specific conductance of highly purified Water can be taken as a dilute solution water is 5478x10-6S mI Calculate the of a strong electrolyte concentration of hydrogen ion in water 2+A0=0.05481S·mo I H K K 478×10-S C Mm 0.0548 ISmol =0.9995×104mol.m 1×10-mold
4. Determine ion product of water Water can be taken as a dilute solution of a strong electrolyte CH+ = COH- = Kw 1/2 m m,H m,OH c + − = = + The specific conductance of highly purified water is 5.478 10-6 S·m-1 . Calculate the concentration of hydrogen ion in water. -1 2 m m,H m,OH + − 0.05481S mol m = + = 6 1 1 2 m 4 3 7 3 5.478 10 S m 0.05481S mol m 0.9995 10 mol m 1 10 mol dm c − − − − − − − = = = §7.3 Applications of Conductivity Measurement
87.3 Applications of Conductivity Measurement 5. Conductometric titration(the way to determine endpoint) The conductance variation of a solution during titration can serve as a useful method to follow the course of the reaction Na*+ OH+(HCD)=Nat+Cl+(H++Cl) 5.1920.525.1979136.30 B B Precipitation reactions, e neutralization reactions, dpoint coordination reactions
5. Conductometric titration (the way to determine endpoint) The conductance variation of a solution during titration can serve as a useful method to follow the course of the reaction. Na+ + OH- + (HCl) = Na+ + Cl- + (H+ + Cl- ) 5.19 20.52 5.19 7.91 36.30 Precipitation reactions, neutralization reactions, coordination reactions A B C A’ B’ C’ V / ml / S·m-1 endpoint §7.3 Applications of Conductivity Measurement
87.3 Applications of Conductivity Measurement 5. Conductometric titration 第30巷 分析化学(FEHA研究简报 第7期 Canes Joumml af Amlytcal Chems 846-848 酸碱电导滴定法测定壳聚糖脱乙酰度 贾之慎李秀玲 浙江大学化学系,杭州310029) 5} 图1NaOH滴定的电导滴定曲线 R-NH C+ Na +OH =R-NH+C +Na +ho Fig. 1 Conductometnc titration curve of naOH 滴定剂的浓度应10倍于被滴定液的浓度
5. Conductometric titration §7.3 Applications of Conductivity Measurement