$A$ substance has no mass. Can one consider it as matter?

State whether the following statement is true or false:
The diffusion in liquids depends upon the thickness (viscosity) as well as on the chemical nature of the diffusing liquids.

In which state of matter is the process of diffusion fastest?

When water gets solidified into ice,then heat is

Alka was making tea in a kettle. Suddenly she felt intense heat from the puff of steam gushing out of the spout of the kettle. She wondered whether the temperature of the steam was higher than that of the water boiling in the kettle. Comment.

Name the state of matter in which
$(i)$ layers of particles can slip and slide over one another easily.
$(ii)$ particles just move around randomly because of very weak force of attraction.