Question

how can matter changes its state​

Answer 1

A substance may exist in any of the three states of matter (i.e. solid, liquid or gas) depending upon the conditions of temperature and pressure. By changing the conditions of temperature and pressure, a substance can be made to exist as solid, liquid or a gas.

Answer 2

matter are Interchangeable from one state to another. if we decrease intermolecular distance matter changes it's form. we can have liquid from solid like by heating ice to water. further heating cause more intermolecular distance ie gaseous ie vapour. Reverse is also true like if you increase pressure under low temperatures gas can be converted to liquid and further increase will turn it to solid