Oxygen and Oxides

Oxygen is quite a common element - it occurs naturally in the atmosphere. It combines with many other elements to make compounds that have very different properties. This post details the properties of oxygen and its compounds, and how the compounds can be tested for, identified or made.

Chemistry - Oxygen and Oxides


Unpolluted, dry air is made up of approximately 78.1% Nitrogen, 21% Oxygen, 0.9% Argon and 0.04% Carbon Dioxide. Oxygen is very easy to test for as it relights a glowing splint.

Identifying and testing for oxide compounds
There are two types of oxide compounds: metal oxides and non-metal oxides.
Most Metals Oxides don’t either react with, or dissolve in, water – those that do tend to form alkaline solution. Non-metal oxides often react with water to form acidic solutions – common exceptions are water and carbon monoxide.


Carbon Dioxide
Oxygen and carbon can form the covalent compound carbon dioxide. It can be made using the reaction  between dilute hydrochloric acid and calcium carbonate (also known as marble chips).
Carbon dioxide can be tested for with lime water. When mixed, the lime water turns a milky colour. Alternatively, you can test for it using a glowing splint. While oxygen alone will fuel a fire, carbon dioxide makes a glowing splint go out. Carbon dioxide is is used in fizzy drinks because it dissolves in water under pressure, and to put out electrical fires where using water could cause problems.






This article is due to be added to shortly.