ION-ECR

ION-ECRIon Mobility: Transference Number of IonsAnalysis of Electrochemical ReactionsDates of the Experiment7-17-20148-30-201410-11-2014ION

To determine the transference numbers of nitrate and hydronium ions

To discuss the effect of mass on the transference number of an ion

ObjectivesECR

To describe the reactions that occur in the cathode and anode regions of the transference vessel and copper coulometer

To analyze the thermodynamic properties and material balance of the electrochemical reactions

ObjectivesTheoretical BackgroundElectrochemistry is the study of the interchange of chemical and electrical energy.

It is concerned with processes that involve redox reactions:The generation of an electric current from a spontaneous chemical reactionThe use of a current to produce chemical changeION-ECRTheoretical BackgroundAn electrochemical cell is a device capable of either generating electrical energy from chemical reactions or facilitating chemical reactions through the introduction of electrical energy.Galvanic/voltaic cellElectrolytic cell

It consists of two electrodes, or metallic conductors, in contact with an electrolyte, an ionic conductor (which may be a solution, a liquid or a solid.

ION-ECRThe Electrolytic Cell

power source provides electrical current and is responsible for the charges of electrodeselectrodes conductors used to establish electrical contact with a nonmetallic part of a circuit anode the positively charged electrode, it attracts anions, where oxidation takes placecathode the negatively charged electrode, it attracts cations, where reduction takes placeelectrolyte is the ionic compound in its molten or aqueous state. It provides mobile electrons that allow electrical conductionION-ECRThe Experimental Set-upION-ECR

e-e-e-e-e-e-e-e-e-e-e-e-e-The CoulometerION-ECRThe reactions:

Anode: Cu(s) Cu2+(aq) + 2e-

Cathode: Cu2+(aq) + 2e- Cu(s)

The Transference VesselION-ECRObservations:

AnodeCathodeFormation of bubblespresentpresentConcentration of HNO3increaseddecreasedDisintegration of the carbon electrodepresentabsentThe Transference VesselION-ECRThe reactions:

Anode: 3H2O 6H+ +3/2 O2 (g)+ 6e-Cathode: 6H+ + 6e- 3H2 (g)

Net:3H20 3H2 (g) +3/2 O2 (g)

The Transference NumberION-ECRIt is the fraction of the total current that is carried by the ionAlso called transport numberHittorf transference numbers are experimentally obtainable through resulting characteristic changes that occur in the cathode and anode of an electrochemical cellRelated to current transport, charge transport, ion mobilities, ionic conductivitiesIf cationic species have higher ion mobility, more of these species are transported from the anode to the cathode region whereas in the same period, less anionic species are transported from the cathode to the anode areaThe Gibbs Free Energy of Reaction ION-ECRA negative value would indicate spontaneityA positive value would indicate non-spontaneityData and ResultsT=27CGroup Codet-t+t+/t-ChE412L01THURS0.2557760.744223512.909663ChE412L06THURS0.2773740.722625972.60524ChE412L07THURS0.4081250.591874861.450229MEAN0.3137590.686241452.321711Standard Dev0.8283970.067307270.628638Data and ResultsT=28CGroup Codet-t+t+/t-ChE412L02THURS0.1938320.806168164.159111ChE412L03THURS0.1725490.827451124.795459ChE412L04THURS0.1522480.847751985.56823ChE412L05THURS0.2549270.745072992.922691MEAN0.1933890.806611064.361373Standard Dev0.0384510.038451310.968975Data and ResultsT=27CGroup Codeqed [C]qmd [C]GedGmdPercent difference (%)ChE412L01THURS271.0368271.2333.3753333.5760.06016696ChE412L06THURS228.9768253.7256281.64143312.08259.75417122ChE412L07THURS269.3666270.75331.32088333.02250.51096132MEAN256.4601265.2252315.44587326.227standard dev19.445588.13352015323.918059768.663917Data and ResultsT=28CGroup Codeqed [C]qmd [C]GedGmdPercent difference (%)ChE412L02THURS269.5184264.6331.50765325.4581.85881088ChE412L03THURS276.1994270339.7253332.12.29608645ChE412L04THURS331.4697261.6407.70772321.76826.7085965ChE412L05THURS271.796271.2334.30912333.5760.21977655MEAN287.2459266.85353.31245328.2255standard dev25.645323.92014030431.543745194.8217726TEMPERATURE Ct-t+t+/t-250.170.835270.31380.686242.321280.19340.806611064.361Data and ResultsTEMPERATURE Cqed [C]qmd [C]GedGmd27256.46265.2252315.446326.22728287.246266.85353.312328.2255Statistical Treatment

Statistical Treatment

ConclusionION-ECRHittorfs rule t+/t- = v+/v-21