Frequently Asked Questions on Chapter 2: Is Matter Around Us Pure
What is meant by a substance?
It is a pure single form of matter. A substance has definite properties and compositions. Example – Iron
What type of mixtures are separated by the technique of crystallization?
The technique of crystallization is used to separate solids from a liquid solution. It is linked to precipitation, but in this technique, the precipitate is achieved in a crystal form which exhibits extremely high levels of purity. The principle of crystallization can be applied to purify impure substances.
How would you confirm that a colourless liquid given to you is pure water?
We can confirm if a colourless liquid is pure by setting it to boil. If it boils at 100°C it is said to be pure. But if there is a decrease or increase in the boiling point, we infer that water has added impurities, hence not pure.
Er. Aman Blogger, Educator