1 / 6

Thermodynamis of electrolyte solutions I

Thermodynamis of electrolyte solutions I. Sähkökemian peruseet KE-31.4100 Tanja Kallio t anja.kallio@aalto.fi C213. CH 2.1-2.3, 2.6. Components and species. component - independent of the other particles in the system neutral particles.

kiley
Download Presentation

Thermodynamis of electrolyte solutions I

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Thermodynamis of electrolyte solutions I Sähkökemianperuseet KE-31.4100 Tanja Kallio tanja.kallio@aalto.fi C213 CH 2.1-2.3, 2.6

  2. Components and species component - independent of the other particles in the system neutral particles species – all the particles in the system neutral and charged particles equilibrium constants electroneutrality Example electrolyte: aqueous acetic acid components: CH3COOH and H2O species: CH3COOH,H2O,CH3COO-, H+,OH-,

  3. finnerorgalvapotential surfacepotential outerorvoltapotential Electrochemical potential Conventions and standard states (T = 25oC, p = 1 atm): elements in their stable state of aggregation proton in aqueous solution (all temperatures) electrons in any metal ions in pure metal state functions dU= dq + dw • dwcaninclude • volumechange - PdV • streching - Fdl • surface tension – gdA • electrical – fdqe • etc.

  4. Activity of non-electrolytes molefraction(mooliosuusasteikko) m* = 1.0 mol/kg ; yi= 1 molality (molaalisuusasteikko) molarity, moleularconcentration (molaarisuusasteikko) c* = 1.0 mol/dm3; gi = 1 • Measuring activity coefficient • Colligative properties – activity of solvent • Freezing point depression (most used) • Boiling point elevation • Osmotic pressure • Vapour pressure depression • Potentiometric methods S Sanjari, M. Nosrati, A. Haghtalab, Fluid Phase Equilibria 277 (2009) 107

  5. Activity of an electrolyte electroneutrality: u+z+ + uz = 0 electrochemical potential of an electrolyte: by definition: u= u+ + uand thus to estimate activity coefficients for ions it has been agreed that and mean activity coefficient (keskiaktiivisuuskerroin) Can be measured!

  6. Osmotic pressure only solvent, e.g. water, permeates trough the membrane osmotic pressure results from imbalance in chemical potential of the solvent p p + p in equilibrium as water is incompressible strong solution osmotic membrane diluted solution a if phase b is pure water b van’tHoffequation

More Related