From: Andrew Lorimer Date: Thu, 18 Apr 2019 06:58:40 +0000 (+1000) Subject: [chem] electrolysis intro X-Git-Tag: yr12~167 X-Git-Url: https://git.lorimer.id.au/notes.git/diff_plain/b0d3855697cc5e735e63eb2e9776333f3b9a466c?hp=9b4ce53d414fedba7ccafc9534dee37f57d74372 [chem] electrolysis intro --- diff --git a/chem/electrochemistry.md b/chem/electrochemistry.md index e439add..8436dd6 100644 --- a/chem/electrochemistry.md +++ b/chem/electrochemistry.md @@ -80,3 +80,29 @@ Used for vehicles/long-lasting applications. ce{H2} may be replenished. - **Alkaline fuel cell** - ce{KOH(aq)} electrolyte, ce{H2(g)} from tank, ce{O2(g)} from atmosphere, water out of hydrogen side - **Acid fuel cell** - ce{H3PO4} electrolyte, water out of oxygen side +## Electrolysis reactions + +- Opposite of reactions in electrochemical (galvanic) cells +- Non-spontaneous +- Electrical energy $\rightarrow$ chemical energy + +### Electroplating + +- For each ion going into plated object, an ion is replaced from the anode (+ve) +- Electrolyte balances charges + +### Coulomb's law + +$$Q=It$$ + +### Faraday's first law + +$$m \propto Q$$ + +i.e. mass produced at cathode is proportional to charge supplied + +*Faraday* - charge on 1 mol of electrons = 96500 C. + +### Faraday's second law + +> To produce one mole of substance by electrolysis, a whole number of mole of electrons is needed