4.2a Metals & Metallic Alloys L1 Retrieval

What is ore?

• Rock found in the earths crust

• Rock that contains metal that can be economically extracted

• Rock that is found deep in the earth's mantle

• Rock that contains minerals

The two different ways of extracting metal form ore are _____&_____

Why might electrolysis be used instead of smelting?

• Electrolysis is faster than smelting

• Electrolysis is most inexpensive

• Electrolysis is used on highly reactive metals that form strong bonds within the ore.

• Electrolysis is used on low reactive metals that form weak bonds within the ore

The rate at which a metal cools can affect the grain size. True or false, a quickly cooled metal increases brittleness while decreasing tensile strength, toughness and ductility

• True

• False

Work hardening increases the hardness of a metal. What property does work hardening also increase?

• Malleability

• Toughness

• Brittleness

• Ductility

What is the purpose of annealing metal and when does metal need to be annealed?

• Annealing is used to remove dents after work hardening

• Annealing is used to toughen the metal after work hardening

• Annealing is used to soften the metal after work hardening

• Annealing is used to harden the metal after tempering

Why are metals not useful in their pure form and need to be alloyed?

• Most metals are too soft and brittle

• Most metals are too tough and brittle

• Most metals are too hard and difficult to shape

• Most metals are too expensive

True or false, annealing regrows a new grain structure (recystallisation) which allows it to be further work hardened.

• True

• False

True or false, metal cannot be recycled indefinitely because it degrades in quality

• True

• False

Recycled aluminium uses _____ less energy than mining and processing bauxite.

• 65%

• 75%

• 85%

• 95%