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Reactivity series - Coggle Diagram
Reactivity series
reactivity series
definitions
oxidation: gain of oxygen OR loss of electrons
reduction: loss of oxygen OR gain of electrons
redox: a reaction in which both oxidation and reduction occur
oxidising agent: causes another reactant to be oxidised and is reduced itself
reducing agent: causes another reactant to be reduced and is oxidised itself
displacement reactions
You can see if one metal is more reactive than another by using displacement
reactions:
Easily seen when a salt of the less reactive metal is in the solution
More reactive metal gradually disappears as it forms a solution
Less reactive metal coats the surface of the more reactive metal
reactions of metals
A few reactive metals will react with cold water
products are a metal hydroxide (forming and alkaline solution) and hydrogen gas
most meats react with acid
acid + metal → salt + hydrogen
almost all metals react with oxygen
metal + oxygen → metal oxide
Only metal that does not react with any of the above is gold, because it is extremely unreactive
You can therefore deduce the relative reactivity of some metals by seeing if they react with water (i.e. VERY reactive), acid (reactive), and oxygen (not that reactive)
rusting
Both air and water are necessary for iron to rust – i.e. oxidation – gain of oxygen
results in corrosion
prevention of rusting
barrier methods
rust can be prevented by coating iron with barriers that prevent the iron from coming into contact with water and oxygen
However, if the coatings are washed away or scratched, the iron is once again exposed to water and oxygen and will rust
galvanisation/ sacrificial protection
Galvanising is a process where the iron to be protected is coated with a layer of zinc
ZnCO3 is formed when zinc reacts with oxygen and carbon dioxide in the air and protects the iron by the barrier method
If the coating is damaged or scratched, the iron is still protected from rusting because zinc preferentially corrodes as it is higher up the reactivity series than iron
The iron stays protected as it accepts the electrons released by zinc, remaining in the reduced state and thus it does not undergo oxidation
The electrons donated by the zinc react with hydrogen ions in the water producing hydrogen gas:
Zinc therefore reacts with oxygen and water and corrodes instead of the iron
reactivity series
potassium, sodium, lithium, calcium, magnesium, aluminium, carbon, zinc, iron, hydrogen, copper, silver and gold