Oxidation,Reduction and Redox Flashcards
What is oxidation?
Loss of electrons
What is reduction?
Gain of electrons
Why is oxidation and reduction known as redox reactions?
They occur simultaneously in a reaction because one species loses electrons which are then donated and gained by the other species
What is oxidation number?
It gives the oxidation states of an element or ionic substance
What are the rules of oxidation states?
•OS of an element is zero
•OS in a neutral compound add up to zero
•OS in a charged compound add up to the total charge
•H has an OS of +1
•O has an OS of -2
•All halogens have an OS of -1
•Group 1 metals have an OS of +1
What is an oxidising agent?
It accepts electrons from the species that is being oxidised. Therefore gains electrons and is reduced
This is seen as a reduction in oxidation number (gets more negative)
What is a reducing agent?
It donates electrons to the species being reduced. Therefore it loses electrons and is oxidised. This is seen as an increase in oxidation number (gets more positive)
What are half equations used to show?
The seperate oxidation and reduction reactions that occur in a redox reaction.
They must be balanced in terms of species present and the charges of the species in both sides of the equation
How can you balance redox equations?
Use oxidation states
The number of atoms of each element, one each side must be equal
The total charge on each side must be the same
What is oxidation state?
A number which represents the number of electrons lost or gained by an atom of that element in the compound
(if electrons lost number is positive, if gained number is negative)
What happens during a redox reaction?
Electrons are transferred from one species (element) to another
One element is oxidised whilst another is reduced
