1.7 Oxidation, Reduction And Redox Flashcards
How can we remember oxidation and reduction?
OIL RIG
What does OIL RIG stand for?
Oxidation is loss
Reduction is gain
(Referring to electrons)
What is redox?
Something being oxidised and something being reduced
How to form simple half equations?
Write the atom/ion and what it is being transferred to
Put the sufficient amount of electrons on either the left or right depending on whether it has been oxidised or reduced
If something is being oxidised where in the half equation do the electrons go?
On the right side of the arrow
Electrons lost = oxidation
If something is being reduced where in the half equation do the electrons go?
On the left side of the arrow
Electrons gained = reduction
(beyonce to the left to the left everybody know’s it reduction to the left)
What is oxidation state?
Tells us how many electrons have been lost or gained
It is another method of interpreting redox reactions
Where should you write the oxidation states?
Underneath the formula
What are the rules for oxidation state?
Atoms of elements OS = 0
Simple ions the OS is the charge of the ion
Compounds the sum of the OS = 0
Covalent molecules are assumed to be ionic
Polyatomic ions the OS equals the overall charge of the ion
How does electronegativity affect oxidation state?
The more electronegative a compound it is going to have a negative oxidation state
The less electronegative a compound it is going to have a positive oxidation state
What are the fixed oxidation states of group 1 and 2 metals?
Group 1 = +1 OS
Group 2 = +2 OS
What is the oxidation state of aluminium?
+3
What is the oxidation state of oxygen? Exceptions?
-2
Except in peroxides and F2O
What is the oxidation state of Fluorine?
-1
What is the oxidation state of chlorine? Exceptions?
-1
Except in compounds with O or F
What is the oxidation state of hydrogen? Exceptions?
+1
Except when bonded in a metal hydride = -1
What does an increase in oxidation state from the reactant to the product side show?
Oxidation
What does an decrease in oxidation state from the reactant to the product side show?
Reduction
It literally reduces
How do you write more complex half equations?
Write down the formulae of the reactants and products and then balance the equation
Balance the oxygen by adding water
Balance the hydrogen by adding H+ ions
Balance the charges by adding electrons
Why do you add water in more complex half equations?
Redox reactions are aqueous
Why do you add hydrogen ions in more complex half equations?
Redox reactions are acidic
Which side are the electrons normally added to in more complex half equations?
The side with the hydrogen ions
What is an oxidising agent?
An electron acceptor
If it is reduced it is the oxidising agent
What is a reducing agent?
An electron donor
If it has been oxidised it is the reducing agent
How do you form overall redox reactions?
Combine the pair of half equations
You have to make sure the electrons in both equations are equal so you can cancel them out in the final equation
Therefore multiply one or both of all the equation so there are equal amounts in both the half equations
How do you actually merge half equations?
Write all the reactants on one side and all the products on the other (after you multiplied accordingly)
Then cancel/simplify the long equation
