Rusting

Question 1

Define Rusting

Answer 1

A slow chemical reaction of IRON with oxygen in the air in the presence of water

Question 2

True or false

Rusting is a form of corrosion

Answer 2

True

Question 3

Define corrosion

Answer 3

Process where a metal is damaged or weakened by a chemical reaction

Question 4

True or false

All metals corrode to the same extent

Answer 4

False

More reactive metals usually corrode faster than less reactive metals

Question 5

True or false

Gold and platinum are considered the least reactive metals

Answer 5

True
That is why it is used in jewellery
The don’t corrode after many years

Question 6

How does rust form

Answer 6

When IRON react with oxygen in the presence of moisture (water)
Water is needed for the rusting process

Question 7

What colour is rust

Answer 7

Orange-red-brown colour solid

Question 8

Info …

Answer 8

The reaction produces a complex compound that contains iron oxide

Question 9

Why will something rust faster in Cape Town than here in Johannesburg

Answer 9

It is near the cost and there is more water vapour in the air meaning that the combination of water air and iron is more reactive meaning that rust will occur faster

Question 10

True or false

Rust happens faster when there are impurities in the water like salt

Answer 10

True

Question 11

True or false

Rust stops at some point

Answer 11

False
Rust is a continues process that slowly eats away at the metal that will later on create holes on the SURFACE and break it down

Question 12

What ways can we prevent things from rusting

Answer 12

Painting the iron 
Using the oil 
Bars protect ships 
Galvanised iron 
INCLUDING 
Chrome plating 

PUB GIC

Question 13

Define the method of :Painting iron to prevent rust

Answer 13

When you paint the metal it prevents the metal from coming into contact with water and oxygen in the air for example we paint ships ,bridges ,fences and certain structures to protect them from resting but if it is scratched the metal underneath can start to rust

Question 14

Define the method of :Using oil to prevent rust

Answer 14

When we apply a layer of oil to prevent rust by repelling water as oil does not mix with water so water does not come into contact with the metal underneath
Eg for bicycles

Question 15

Define the method of :Using bars to protect ships

Answer 15

Ships and pipelines are always in contact with water, so to prevent rust we attach bars of more reactive metal to them ,magnesium alloys and zinc a more reactive than iron the bar corrodes instead of the iron the corrosion of the bar helps the iron stay intact ,the bar slowly dissolves and must be renewed as quickly as possible.

Question 16

Define the method of :Galvanising iron to prevent rust

Answer 16

The iron is coated with a thin layer of a more reactive metal that protects the iron .Roofs are generally dipped into molten zinc .Even if the surface is scratched the zinc will corrode before iron

Question 17

Define electroplating

Answer 17

To use electrolysis to cover one metal with a layer of another metal

Question 18

Define the method of : Chrome plating to prevent rust

Answer 18

It is used to protect steel or iron ,electrolysis is used in a process called electroplating the electrolysis reaction deposits a thin layer of chromiumon the steel . This protects the seal because chromium does not rust it also forms a shiny attractive surface and is therefore often used to produce components of motorbikes and cars