Metal Alloys

Question 1

What are gold alloys used for?

Answer 1

jewellery

Question 2

Why are alloys harder than metals?

Answer 2

atoms in a metal are all the same size so can slip and slide over each other but atoms in an alloy are all different sizes which disrupts the layers making it harder

Question 3

What is gold measured in?

Answer 3

carats

Question 4

What is the percentage of gold in 24 carats?

Answer 4

100%

Question 5

Why is stainless steel used for cutlery?

Answer 5

resists corrosion

Question 6

What are aluminium alloys used for?

Answer 6

drink cans

Question 7

When does corrosion occur?

Answer 7

metal reacts with chemicals in the environment

Question 8

What are the two ways to prevent corrosion?

Answer 8

• surface coating
• sacrificial protection

Question 9

Rusting equation

Answer 9

Iron + water + oxygen –> hydrated iron oxide

Question 10

What is surface coating?

Answer 10

applying a layer on top of a metal to stop the metal’s surface from being in contact with the air

Question 11

What are som of the material used to coat the metal?

Answer 11

• paint
• oil/grease
• plastic coating
• less reactive metal
• oxide layer

Question 12

What is electroplating?

Answer 12

coating the metal with a less reactive metal

Question 13

What does aluminium oxide produce?

Answer 13

oxide layer on the surface of the metal which prevents corrosion

Question 14

What is sacrificial protection?

Answer 14

block of a more reactive metal are attached to ships so the sea water will now corrode the more reactive metal rather than the iron in the steel as the more reactive metal always reacts first

Question 15

What is galvanising?

Answer 15

if steel has a coating of zinc, the air and water will corrode zinc rather than the steel underneath