Question

does the mass change if be converted water into gas

Answer 1

When water (a liquid) boils, it turns intosteam (a gas); this is called vaporisation. ... A solid substance at its melting point has less energy than the same mass of the substance when it is a liquid at the same temperature. To change a solidinto a liquid, or a liquid into a gas, requires heat energy.

Answer 2

Particles stay the same unless there is a chemical change whether the matter is solid, liquid or gas.

When substances change state there is no change in mass so if 100 g of ice is melted 100g of water are formed this will boil to form 100g of steam (this is called "conservation of mass").