Physical and chemical properties

In a nutshell

All substances have a set of properties. Properties can be physical or chemical. 

Properties

A property is how a substance looks or behaves. It is important to be aware of a substance's properties as this can allow you to select the most appropriate material for the job.

Example

Aluminium is used to make saucepans as it is a very good conductor of heat.

Physical properties

A physical change is when a substance changes its physical state from solid, liquid or gas. The process occurring can usually be observed.  

Example 1

$$H_2O$$​ going from liquid water to solid ice. 

Example 2

Other examples of physical properties are: brittleness, whether a material is magnetic or not and melting/boiling point. 

Chemical properties

A chemical change occurs during a chemical reaction. During the reaction, one or more new substances are formed. Chemical reactions cannot simply be observed just by looking at a material, you have to carry out a reaction or experiment.

Example

An example of measuring chemical properties is testing for pH of liquids.

Hydrochloric acid has a low pH between $$0-2$$, which means it is acidic. Water has a ph of $$7$$, this means it is neutral. Bleach on the other hand has a pH of $$12-13$$​, therefore it is alkaline.