Preparation of oxygen

What is oxygen?

Oxygen is a gas that makes up about 21% of the air we breathe.

How is oxygen made in the lab?

Oxygen can be made by breaking down a substance called hydrogen peroxide. When hydrogen peroxide breaks down, it forms oxygen gas and water.

The chemical reaction looks like this:

Hydrogen peroxide → Water + Oxygen

$2H_2O_2 \rightarrow 2H_2O + O_2$

Oxygen can be prepared using the following method:

• Decomposition of hydrogen peroxide using manganese (IV) oxide as a catalyst
• Heating potassium chlorate in the presence of manganese (IV) oxide
• Heating compound rich in oxygen e.g. mercuric oxide and potassium permanganate
• Fractional distillation of liquid air (industrial process)

Diagram of preparation of oxygen

Oxygen can be manufactured by decomposition of hydrogen peroxide.

Decomposition of hydrogen peroxide

Hydrogen peroxide decomposition leads to production of oxygen gas and water.

Equation:

$2H_2O_2 \rightarrow 2H_2O_{(l)} + O_{2(g)}$

Method of collection

Oxygen is collected by downward displacement of water because it is slightly soluble in water.

A catalyst is a substance that alters the rate of a chemical reaction but itself remains chemically unchanged at the end of the reaction.