1c) - Oxidising And Reducing Agents Flashcards
What is reduction
Reduction is a gain of electrons by a reactant in any reaction
What is oxidisation
Oxidisation is a loss of electrons by a reactant in any reaction
What happens during a redox reaction
In a redox reaction reduction and oxidation take place at the same time
What do elements with low electronegativities form ions by
Elements with low electronegativities tend to form ions by loosing electrons and so act as reducing agents e.g. alkali metals
What do elements with high electronegativities form ions by
Elements with high electronegativities tend to form ions by gaining electrons and so act as oxidising agents e.g. hallogens.
What are the steps of balancing ion electron equations
1 - balance the element
2- balance oxygens by adding H20
3- balance hydrogens by adding H+ ions
4- balancing the charges by adding e- electrons (with side H+ ions)
In the periodic table where are the strongest reducing agents
In the periodic table, the strongest reducing agents are in group 1
In the periodic table where are the strongest oxidising agents
the strongest oxidising agents are in group 7
Which type of agent is hydrogen peroxide
Hydrogen peroxide Is a molecule that is an oxidising agent
What are dichromate and permanganate ions agents of
dichromate and permanganate ions are group ions that are strong oxidising agents in acidic solutions
What type of agent is carbon monoxide
carbon monoxide is a gas that can be used as a reducing agent
What does the electrochemical series represent
The electrochemical series represents a series of reduction reactions.
Where are the strongest oxidising agents on the electrochemical series
The strongest oxidising agents are at the bottom of the left-hand column of the electrochemical series.
Where are the strongest reducing agents on the electrochemical series
The strongest reducing agents are at the top of the right-hand column of the electrochemical series.
Where are the electrons in a reduction reaction
In an ion electron equation if the electrons are on the left hand side of the arrow (reduction)
Where are the electrons in an oxidation reaction
If they are on the right hand side of the arrow (oxidation)
What can there not be in a final redox equation
In redox reactions there should be no electrons in the final equation
How can you decide what is being oxidised and what is being reduced
- the substance further down will be reduced
- the substance further up will be oxidised. Oxidation is the opposite of reduction so you flip the equation
What is an oxidising agent
Allows something to be oxidised by being reduced
What is a reducing agent
Allows something else to reduce by being oxidised
What happens to electrons in oxidising agent
An oxidising agent is a substance that accepts electrons ( it is reduced)
What happens to the electrons in a reducing agent
A reducing agent is a substance that donates electrons ( it is being oxidised)
What can oxidising agents be used for
- kill fungi and bacteria, and can inactivate viruses.
What are oxidising agents ideal for
The oxidation process is also an effective means of breaking down coloured compounds, making oxidising agents ideal for use as ‘bleach’ for clothes and hair.
Hydrogen peroxide
Hydrogen peroxide is a molecule that is an oxidising agent
Dichromate and permanganate ions are …
Dichromate and permanganate ions are group ions that are strong oxidising agents in acidic solutions
Carbon monoxide
Carbon monoxide is a gas that can be used as a reducing agent
What is the colour change in permanganate solution
Purple to colourless
If electrons are on the left hand side of the arrow
Reduction
If electrons are on the right hand side of the arrow
Oxidation
Method for writing redox equation
- Decide what is being oxidised and what is being reduced, write the ion electron equation for both
- Multiply through so the number of electrons being lost is the same as the number of electrons being gained
- Combine the ion electron equations and cancel electrons
- If you’ve done this correctly the total charge should be the same on either side
