Chemistry chapter 6

• oxidation is gain of oxygen and loss of electrons
• reduction is loss of oxygen and gain of electrons
• Oxidation and reduction always take place together
• Another name for burning is combusion
• the term redox comes from Reduction + Oxidation
• if a substance loses electrons during a reaction, it has been oxidised
• Half equation shows the electron transfer in a reaction
• An oxidation number tells you how many electrons each atom of an element has lost, gained or shared, in forming a compound
• the oxidation number for hydrogen is +1
• The oxidation number for sodium and the other group 1 metals is +1
• The oxidation number for calcium and the other group 2 metals is +II
• The oxidation number for aluminum, group III is +III
• The oxidation number of oxygen (except in peroxides) Group VI is -II
• The oxidation number for chlorine and the other group VII non-metals, in compounds without oxygen is -I
• An oxidising agent oxidises the reducing agent while it itself is reduced
• A reducing agent reduces the oxidising agent while it itself is oxidised
• if a reducing agent is present, the strong purple colour of potassium manganate(VII) will fade
• potassium iodide is used to test for oxidising agents, the solution goes from colourless to red-brown