So, how much water have you added to the milk today?
What are you saying sir? This milk is 100 % pure.
From above conversation…..
How often do we use words such as ‘pure milk’ and ‘pure water’? Have you ever wondered what ‘pure’ really means?
How to recognize a pure substance?
One can recognize a pure substance by its properties such as density, melting point, refractive index, electrical conductivity and viscosity.
Then, how can we define a pure substance?
A pure substance has fixed composition and fixed properties which cannot be easily separated by physical methods.
For example, pure water boils at 100°C at one atmospheric pressure and ice freezes at 0°C. These are the properties of all samples of pure water, regardless of their origin. Pure water contains only two hydrogen atoms and an oxygen atom which cannot be separated by physical methods.
In science, a pure substance is either an element (Example: iron) or a compound (Example: Sodium chloride).
Air we breathe is not a pure substance but a mixture of gases
Milk is a mixture that contains liquid fat, protein and water.