From: Andrew Lorimer Date: Tue, 23 Apr 2019 10:55:52 +0000 (+1000) Subject: [chem] Dichtl's clarifications on electrolysis intro X-Git-Tag: yr12~160 X-Git-Url: https://git.lorimer.id.au/notes.git/diff_plain/3fa876164f81b7623c9a58023b256c70acfffd1c [chem] Dichtl's clarifications on electrolysis intro --- diff --git a/chem/electrochemistry.md b/chem/electrochemistry.md index 8436dd6..7996a24 100644 --- a/chem/electrochemistry.md +++ b/chem/electrochemistry.md @@ -56,6 +56,8 @@ Usually one member of pair is used as electrode (except for *inert electrodes*, ## Electrochemical/galvanic cells +Spontaneous reaction + 1. Find two half reactions involved (between electrode and solution) 2. Higher equation will proceed left to right 3. Lower equation will proceed right to left @@ -82,9 +84,21 @@ Used for vehicles/long-lasting applications. ce{H2} may be replenished. ## Electrolysis reactions +- Occurs when electricity passes through ionic compound or electrolyte solution - Opposite of reactions in electrochemical (galvanic) cells - Non-spontaneous - Electrical energy $\rightarrow$ chemical energy +- Anode +ve; cathode -ve +- Cathode & anode swap relative to galvanic cell +- Molten e.g. ce{Na+(l)} vs electrolyte e.g. ce{Na+(aq)} +- Molten - use echem series to determine probability of electrolyssis of solution or water +- Min voltage = e_oxidising - e_reducing + +### Factors affecting electrolysis + +- concentration of electrolyte +- - e- values must be "close" for electrolysis rxn to prevail over \ce{H2O} +- nature of electrodes ### Electroplating