Rust happens when an iron gets wet and exposed to oxygen.

Is rust an element, compound, or mixture?

Rust a.k.a ferric oxide is a chemical compound. It is composed of different elements i.e. iron (Fe) and oxygen (O) that bond chemically in a fixed proportion. Thus, it’s neither an element nor a mixture.

Yes, rust is one kind of matter.

And since it’s a matter, it can be classified according to its composition.

In this article, you can learn why rust is considered as compound. Why is it not an element or a mixture.

So, keep reading!

How Do Rust Happens?

Rust happens when iron is exposed to water and oxygen.

You don’t need rain to let iron rust. Placing a piece of iron in a humid area can also induce rust because moisture provides water.

4Fe + 3O2 + xH2O –> 2 Fe2O3.xH2O

Water is needed in this reaction and it acts as an electrolyte.

Is Rust an Element?

No, rust is not an element. Element only consists of a single type of atom while rust is not. Rust consists of different elements that bond chemically.

An element is a standalone matter. It’s only consists of an individual kind of atom.

An element is so pure that it cannot be broken down into different ingredients. It will always be that element.

Oxygen is an example of element. No matter how many times it’s broken down it will always be oxygen.

An element can combine with 1 or multiple other elements and form another kind of thing. When two or more elements combine, they can make compound or mixture.

Is Rust A Compound or Mixture?

Rust is a compound, not a mixture. Rust consists of iron and oxygen that bond chemically in a fixed ratio of proportion. Hence, it’s not a mixture.

In science, a substance is considered as compound if it consists of different elements that form chemical bond(s) the substance must have a fixed ratio of proportion.

CO2 or carbon dioxide is an example of substance. No matter where it’s found, carbon dioxide will always have the molecule of CO2.

Compound is different with mixture.

A mixture is a matter that is composed of various substances that combine physically without fixed ratio of proportion. It means that the same kind of matter can have different proportion of ingredient.

A glass of water and sugar is an example of mixture. Either the sugar is added to the water in a small or big amount, the matter will still be called a glass of water and sugar.

Rust (Fe2O3) has the certain fixed amount of proportion so it’s classified as compound, not mixture.

How to Protect An Iron From Rust?

Rust is not pleasant to see. Rust appears as reddish-brownish small flakes on iron and other metals that contain iron.

There are several ways that you can try to protect the iron from rust. Basically, you need to prevent the oxygen and water from having contact with the iron/metal.

To protect an iron or iron alloy from rust, you can do these things:

  • paint the metal
  • galvanize the metal (give it a zinc coating)
  • give it some oil coating
  • try bluing/tempering if it’s steel
Daniel Smithson

Hi, I'm Daniel Smithson, a Chemistry teacher for over 35-years and the founder of Learning should be fun and accessible to all. Find out more about our mission here:

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