The measurement of transport numbers Hittorf method From 是世是 n Hence,by measuring the change of composition in the cathode (or anode)compartment,the anion transport number t.(or t)can be deduced. PDF文件使用"pdfFactory Pro”试用版本创建fmm,fineprint.com,cn
The measurement of transport numbers Hittorf method From - = + - = + - + n n v v Q Q n n t n n t = - - = + + Hence,by measuring the change of composition in the cathode (or anode) compartment , the anion transport number t - (or t+ ) can be deduced. PDF 文件使用 "pdfFactory Pro" 试用版本创建 fwww.fineprint.com.cn
n;:the mole number of the ions of cathode (or anode) compartment at the initial state n:the mole number of the ions of cathode(or anode) compartment at the final state ne:the mole number of electrons gaining in cathode or lossing in anode nm:the mole number of migration of the ion Example Calculate:t Ag+ Note:The same amount of solvent should be used to calculate ni and ne PDF文件使用"pdfFactory Pro”试用版本创建m,fineprint.com,cn
n i : the mole number of the ions of cathode (or anode) compartment at the initial state nf : the mole number of the ions of cathode (or anode) compartment at the final state ne :the mole number of electrons gaining in cathode or lossing in anode nm:the mole number of migration of the ion Example Calculate:t Ag+ Note: The same amount of solvent should be used to calculate ni and nf . PDF 文件使用 "pdfFactory Pro" 试用版本创建 ÿwww.fineprint.com.cn
Conductance,Conductivity and the Molar Conductivity Conductance---is the inverse of the resistance of a material. G=1/R Units:-1,reciprocal ohm,sometimes the siemens:1S=1Ωl Determining conductance involves measuring the electrical resistance of the solution,and the standard method consists of incorporating a cell of kind into one arm of a bridge and searching for the balance point. PDF文件使用"pdfFactory Pro”试用版本创建wm,fineprint..com,cn
Conductance, Conductivity and the Molar Conductivity Conductance--- is the inverse of the resistance of a material. G=1/R Units: W-1 ,reciprocal ohm, sometimes the siemens:1S=1 W-1 Determining conductance involves measuring the electrical resistance of the solution, and the standard method consists of incorporating a cell of kind into one arm of a bridge and searching for the balance point. PDF 文件使用 "pdfFactory Pro" 试用版本创建 ÿwww.fineprint.com.cn
Fig 26.1.A conductivity cell forming one arm of an ac.bridge. The major complication of the method results from the need to use an alternating current.A direct current would lead to an electrolysis reaction at the electrodes, and so the nature of the solution in their vicinity would change as the measurement proceeded;this is called polarization of the electrodes PDF文件使用"pdfFactory Pro”试用版本创建m,fineprint.com,cn
The major complication of the method results from the need to use an alternating current. A direct current would lead to an electrolysis reaction at the electrodes, and so the nature of the solution in their vicinity would change as the measurement proceeded; this is called polarization of the electrodes PDF 文件使用 "pdfFactory Pro" 试用版本创建 ÿwww.fineprint.com.cn
Conductivity---is the inverse of the resistivity. The resistance of a material increases with its length l but decreases with its cross-section A:RLA.The proportionality coefficient is called the resistivity,and written p (rho),then R=P VA The conductivity K (kappa)is the inverse of the resistivity,and so G=KA几 Units of k:S.m-1 PDF文件使用"pdfFactory Pro”试用版本创建m,fineprint.com,c四
Conductivity--- is the inverse of the resistivity. The resistance of a material increases with its length l but decreases with its cross-section A: R∝ l/A. The proportionality coefficient is called the resistivity, and written ρ(rho), then R=ρl/A The conductivity k (kappa)is the inverse of the resistivity, and so G=kA/l Units of k : S×m-1 PDF 文件使用 "pdfFactory Pro" 试用版本创建 ! www.fineprint.com.cn ÿ