State the two conditions needed for the changes of matter to occur?

All matter can change from one state to another. This is known as interconversion of the states of matter. Matter can change from one state to another under these conditions– i.e. temperature and pressure of the substance.

For example, when we apply pressure on water vapours, they convert into liquid state, that is, there is a change from the gaseous state to the liquid state.

On heating, ice melts to water (solid changes into the liquid state).