Reactivity Series Flashcards
how can metals be arranged in a reactivity series?
- based on their reactions with:
- water
- dilute hydrochloric/sulphuric acid
- based on their displacement reactions between:
- metals and metal oxides
- metals and aqueous solutions of metal salts
what is the order of reactivity of metals?
- potassium
- sodium
- lithium
- calcium
- magnesium
- aluminium
- zinc
- iron
- copper
- silver
- gold
how does the reactivity series work?
A MORE REACTIVE METAL DISPLACES A LESS REACTIVE METAL.
- more reactive metals react more strongly than less reactive metals.
- this means a more reactive metal will displace a less reactive metal from its oxide because it will bond MORE STRONGLY to the oxygen
- similarly, if you put a reactive metal into a solution of a less reactive metal salt then the reactive metal will replace the less reactive metal in the salt.
what are the conditions needed for iron to rust?
- iron corrodes easily
- rusting only happens when irons in contact with both oxygen and water.
- oxidation reaction occurs. the iron gains oxygen to form iron (III) oxide.
- water then becomes loosely bonded to the iron (III) oxide and the result is HYDRATED iron (III) oxide = rust.
how can rusting be prevented by BARRIER METHODS?
- painting/coating with plastic - ideal for big and small structures alike.
- oiling/greasing - used when moving parts are involved e.g. bike chains.
how can rusting be prevented by SACRIFICIAL METHODS/GALVANISING?
involves placing a more reactive metal with the iron. the water and oxygen then react with this sacrificial metal instead of with the iron.
- zinc is often used as a sacrificial metal.
- zinc is more reactive than iron, so the zinc will be oxidised, rather than the iron.
- a coating of zinc can be sprayed onto the object = GALVANISING.
- or big blocks zinc can be bolted to the iron. this is used on ships hulls or on underground iron pipes.
what is oxidation?
the loss of electrons -> OIL
OR the gain of oxygen
what is reduction?
the gain of electrons -> RIG
OR the loss of oxygen
what is a redox reaction?
a reaction where reduction and oxidation happens at the same time.
what is the oxidising agent?
- an oxidising agent ACCEPTS electrons and GETS reduced (electrons)
- the substance that OXIDISES the metal and GETS reduced. (oxygen)
what is the reducing agent?
- a reducing agent DONATES electrons and GETS oxidised (electrons)
- the substance that REDUCES the metal and GETS oxidised. (oxygen)
PRACTICAL: investigate reactions between dilute hydrochloric and sulphuric acids and metals METHOD
- set up three boiling tubes and fill them with equal volumes of dilute hydrochloric acid or dilute sulphuric acid.
- then places pieces of magnesium, zinc and iron in separate test tubes - make sure the size and shape is the same.
- the speed of reaction is indicated by the rate at which the bubbles of hydrogen are given off
- the hydrogen is confirmed by the burning splint test.
PRACTICAL: investigate reactions between dilute hydrochloric and sulphuric acids and metals
RESULTS OF MAGNESIUM
- Dissolves quickly
- gets hot
- gas given off which has the loudest squeaky pop
- colourless solution left
- vigorous bubbling
PRACTICAL: investigate reactions between dilute hydrochloric and sulphuric acids and metals
RESULTS OF ZINC
- bubbles given off.
- metal slowly dissolves.
- faster reaction if heated
PRACTICAL: investigate reactions between dilute hydrochloric and sulphuric acids and metals
RESULTS OF IRON
- very slow bubbling
- faster reaction if heated
