What is electrolysis in a formula?

2H2O (I) - - - >2H2 (g) + O2 (g)

Relative atomic masses needed: Na = 23, Cl = 35.5, H = 1, Cu = 63.5, Al = 27, O = 16 and the molar volume of any gas is 24 dm3 at room temperature and pressure. The common electrode equations you may come across are listed below.

electrode involved: (-) negative cathode or (+) positive anode for the Electrode Equation below

moles of electrons involved (mass of product formed)

example of industrial process where this electrode reaction happens

sodium (-) Na + (l) + e - = = > Na (l)

1 (23g) = 1.0 mol Na metal per mol e-s

electrolysis of molten chloride salts to make chlorine and the metal

chlorine (+) 2Cl - (l/aq) - 2e - = = > Cl2 (g)

2 (71g) = 0.5 mol Cl2 gas (12 dm3) released per mol e-s

electrolysis of molten chloride salts or their aqueous solution to make chlorine

hydrogen (-) 2H + (aq) + 2e - = = > H2 (g)

2 (2g) = 0.5 mol H2 gas (12 dm3) released per mol e-s

electrolysis of many salt solutions to make hydrogen

copper (-) Cu2 + (aq) + 2e - = = > Cu (s)

2 (63.5g) = 0.5 mol Cu deposited per mol e-s

deposition of copper in its electrolytic purification or electroplating

copper (+) Cu (s) - 2e - = = > Cu2 + (aq)

2 (63.5g) = 0.5 mol Cu dissolves per mol e-s

dissolving of copper in its electrolytic purification or electroplating

aluminium (-) Al3 + (l) + 3e - = = > Al (l)

3 (27g) = 0.33 mol Al metal per mol e-s

extraction of aluminium in the electrolysis of its molten oxide ore

oxygen (+) 2O2 - (l) - 4e - = = > O2 (g)

4 (32g) = 0.25 mol O2 (12 dm3) gas released per mol e-s electrolysis of molten oxides

oxygen (+) 4OH - (aq) - 4e - = = > 2H2O (l) + O2 (g)

4 (32g) = 0.25 mol O2 gas (6 dm3) released per mol e-s electrolysis of many salt solutions such as sulphates, sulphuric acid etc. gives oxygen (but chloride salts = = > chlorine)

(Thats some formulas for different elements that are commenly used)