3:Redox 1 Flashcards
In terms of electrons, what is oxidation?
The loss of electrons
In terms of electrons, what is reduction?
The gain of electrons.
In term of oxidation number, what is oxidation?
The increase in oxidation number
In terms of oxidation number, what is reduction?
The decrease in oxidation number
What are reducing agents?
Species in the redox reaction that lose electrons and are oxidised themselves
What is an oxidising agent?
Species in a redox reaction that gain electrons and are reduced themselves
What is the oxidation number of uncombined elements?
Always 0
What is the oxidation number of ions?
The same number as the charge of the ion
What is the oxidation number for group 1 elements?
Always +1
What is the oxidation number for group 2 elements?
Always +2
What is the oxidation number for aluminium?
Always +3
What is the oxidation number for hydrogen?
+1
(except in hydrides where it is -1)
What is the oxidation number for chlorine?
-1
(except if the compound contain F or O - the oxidation number would be a positive value)
What is the oxidation number for fluorine?
Always -1
What is the oxidation number for oxygen?
-2
(except in peroxides it’s -1 and when bonded with fluorine it’s +2)
What is a disproportionation reaction?
When a species is being reduced and oxidised simultaneously
How do you build an ionic half equation in an acidic medium?
1) Balance the species which is changing oxidation state.
2) Balance the oxygen by adding water molecules
3) Balance the hydrogen by adding H+ ions
4) Balance the charges by adding electrons
How do you build an ionic half equation in an alkaline medium?
1) Balance the species which is changing oxidation state
2) Balance the oxygen by adding water molecules
3) Balance the hydrogen by adding H+ ions
4) Remove H+ ions by adding OH- ions to both sides of the equation
5) Balance the charges by adding electrons
