9.2 Uses of metals

What is aluminium used for and why?

• Used in aircraft manufacturing because of its low density

• Used in overhead electrical cables due to low density and good electrical conductivity

• Used in food containers because it resists corrosion(doesn’t rust)

What is copper used for?

used in electrical wiring because of good electrical conductivity and ductility

What is an alloy?

A mixture of a metal with other elements

What are examples of alloy?

• Brass-mixture of copper and zinc

• Stainless steel-mixture of iron, chromium, nickel, carbon

Why are alloys more useful than pure metals?

They can be harder and stronger

Why are alloys harder and stronger than pure metals?

Different atom sizes in alloys prevents them from sliding past each other

What is the use of alloy?

Stainless steel used for cutlery because

• Hardness

• Resistance to corrosion

What is a displacement reaction

When a more reactive element takes the place of a less reactive element in a compound

How to determine metal reactivity

• Observe and compare metal reactions with water, acids and oxygen

• Assess metals based on the speed and intensity of their reactions

• Rank metals from most to least reactivity based on reaction strength

Why does aluminum seem unreactive?

• Aluminium reacts with oxygen in air to form aluminium oxide

• This oxide protects the metal and stops it from reacting with water acids etc