Question

What must be added to water in order to change state from liquid to a gas?
Responses

A more liquidmore liquid

B energy or heatenergy or heat

C more oxygen atomsmore oxygen atoms

D more hydrogen atomsmore

Answer 1

B — energy or heat.

Adding heat increases the water molecules' kinetic energy, allowing them to overcome intermolecular (hydrogen-bond) forces and escape as vapor (evaporation or boiling).