Test Rusting Flashcards
What is rust also know as
Hydrated iron oxide
What is the equation for rusting
Iron + oxygen + water —> hydrated iron oxide
What is corrosion
Metals react with substances in their environment and are gradually destroyed eg rusting
What is rusting
It is the reaction of iron or steel with water and oxygen
Why is rusting a problem
Because it makes iron and steel objects weaker
Ways to stop rusting
Painting
Oiling
Galvanising ( covering in zinc )
Using a sacrificial metal eg magnesium
Why does painting help stop rusting
Paint covers the iron or steel object forming a protective barrier
So oxygen and water can’t pass through the paint
Why does oiling help stop rusting
The oil form a protective barrier around the steel which prevent oxygen and water reacting the steel
Why does galvanising help stop rusting
It covers the steel in zinc which it more reactive and will react instead of the iron
Why does a sacrificial metal (eg magnesium)help stop rusting
Magnesium is more reactive and will react instead of the steel
What is an alloy
It is a mixture of metals
Are pure metals hard or soft
A pure metal is soft
Why are pure metals soft
The layer of atoms high make up a metal can slide over each other
Why are alloyed stronger and harder
Because different elements have different size atoms making it harder to slide over each other
