Which of the following substances in the gaseous state should be called a vapour?
$(i)$ Helium
$(ii)$ Nitrogen
$(iii)$ Carbon dioxide
$(iv)$ Sulphur

What happens to the heat energy that is supplied to a solid once it starts melting?

The kinetic energies of water particles in three vessels $A, B$,and $C$ are $E_A, E_B$,and $E_C$ respectively,where $E_A > E_B > E_C$. Arrange the temperatures $T_A, T_B$,and $T_C$ of the water in the three vessels in increasing order. Provide a reason for your answer.

Which gas is called dry ice? Why?

$(a)$ Enumerate the changes that take place inside the matter during the change of states.
$(b)$ When a solid melts,its temperature remains the same. Give reason.

State whether the following statement is true or false:
The movement of tiny particles in a gas or liquid is called the Tyndall effect.