2d - The Reactivity Series Flashcards
Some metals are more reactive than others, how can they be arranged in order of reactivity? give an example with iron and zinc:
The order of reactivity can be determined by adding dilute hydrochloric acid and water to different metals and observing the rate of reaction.
For example, when hydrochloric acid is added to iron (Fe) then bubbles of hydrogen are produced slowly. However, if the same acid is added to zinc (Zn) then bubbles will be produced more quickly. This tells us that zinc is more reactive than iron.
Why is dilute hydrochloric acid used more then water to test the reactivity of metals?
many metals are too low in the reactivity series to react with water
What 4 metals react with water?
Potassium
Sodium
lithium
calcium
What 8 elements react with acid?
Potassium Sodium lithium calcium magnesium aluminium zinc iron
What metal in the reactivity series doesn’t react with water or acid?
copper
How else can metals be arranged in the reactivity series?
Displacement reactions:
- A metal will displace another metal from its oxide that is lower in the reactivity series. For example, a reaction with magnesium and copper (II) oxide will result in the magnesium displacing the copper from its oxide.
- A metal will also displace another metal from its salt that is lower in the reactivity series. For example, the reaction between zinc and copper (II) sulfate solution will result in zinc displacing the copper from its salt
How do you remember the order of the reactivity series?
Please stop licking cats, Mike, and zip isabellas lovely, hot, cream, soft G(j)acket potato.
What are the conditions needed for iron to rust?
Iron rusts when oxygen and water are present.
What is the equation for iron rust?
Iron + Oxygen + water –> hydrated iron(iii) oxide (rust)
What are some ways rusting can be prevented?
- barrier method
- galvanising
- sacrificial protection
Explain how the barrier method prevents rust:
Rusting may be prevented by stopping the water and oxygen getting to the iron with a barrier of grease, oil, paint or plastic.
Explain how galvanising prevents rust:
Iron can be coated in a layer of zinc, as long as the zinc layer is unscratched it acts as a barrier.
BUT if it is scratched the iron still won’t rust because zinc is more reactive - so will react with the oxygen and water preferentially and will corrode instead. During the process, the zinc loses electrons to form zinc ions.
Explain how Sacrificial Protection prevents iron from rusting?
Zinc, aluminium or magnesium blocks (called sacrificial anodes) are attached to big metal structures e.g ships, rigs etc.
The more reactive metal is oxidised instead of the iron. The corrosion of this other metal prevents the corrosion of iron.
The sacrificial anodes have to be replaced occasionally, when all the metal has corroded.
What is oxidation in terms of gain or loss of oxygen and loss or gain of electrons?
- Oxidation is the loss of electrons. For example a sodium atom (Na) loses an electron to become a sodium ion (Na⁺). Another example is a chloride ion (Cl⁻) losing an electron to become a chlorine atom (Cl).
- Another definition of oxidation is the gain of oxygen. For example if carbon combines with oxygen to form carbon dioxide, the carbon is being oxidised.
What is reduction in terms of gain or loss of oxygen and loss or gain of electrons?
- Reduction is the gain of electrons. For example a sodium ion (Na⁺) gains an electron to become a sodium ion (Na). Another example is a chlorine atom (Cl) gaining an electron to become a chloride atom (Cl⁻).
- Another definition of reduction is the loss of oxygen. For example when aluminium oxide is broken down to produce aluminium and oxygen, the aluminium is being reduced.
