SCI - DISPLACEMENT

What is a displacement reaction?

A displacement reaction happens when a more reactive element replaces a less reactive element in a compound.

Displacement reaction examples (Know at least 3)

1) Iron in Copper Sulfate

2)  Potassium + Water
3) magnesium + water

Iron in Copper Sulfate equation and reaction

Iron + Copper sulphate → Iron sulphate + Copper

✔ Iron dissolves
✔ Pale green iron sulphate forms
✔ Copper coats the nail

 Copper Wire + Silver Sulphate equation and reactions

Copper + Silver sulphate → Copper sulphate + Silver

✔ Silver metal forms on the copper wire.

What happens when Magnesium displaces hydrogen and name the equation and what solution is formed?

When magnesium displaces hydrogen, it reacts with water to form magnesium hydroxide and hydrogen gas. The chemical equation for this reaction is:

 Magnesium + Water → Magnesium hydroxide + Hydrogen

This forms magnesium hydroxide and creates an alkali solution This is because of OH- being released which decides alkaline strength.

Highly reactive in the reactivity series

• Potassium

• Sodium

• Lithium

• Calcium

Moderately reactive in the reactivity series?

• Magnesium
  

• Aluminium
  

• Zinc
  

• Iron
  
  

Low reactivity in the reactivity series

• Silver

• Copper

Inert in the reactivity series

Gold

Equation for when metals react with acids

Metal + Acid → Metal salt + Hydrogen

What happens when metals react with acids

✔ More reactive metals displace hydrogen from acids.
✔ Hydrogen gas is produced

What are the uses of displacement reactions in real life?

Thermite wielding
Extracting Metals from Ores
Stomach acid medicines

Thermite wielding

• Produces intense heat

• Aluminium displaces Iron

✔ Used to repair railway tracks.

Stomach acid medicine

• Some medicines neutralize stomach acid.

• They react with hydrochloric acid to form a salt + water. (e.g sodium bicarbonate)
  

Extracting metals

• Carbon is used to displace metals from their ores.

What are the two non metals used in displacement reactions and how are they used?

Carbon and Hydrogen

→ Used for reducing agents in displacement reactions to extract less reactive metals from their oxides

How does metal react with hydrochloric acid? (word eq.)

Metal + Hydrochloric acid → Metalchloride + Hydrogen