EVERYDAY SCIENCE

Detailed explanation-1: -Water must absorb energy to move from a lower to higher energy phase, i.e., from solid (ice) to liquid during melting and from liquid to gas (water vapor) during evaporation. In each case, the energy absorbed by water is used to change its internal molecular bonding structure.

Detailed explanation-2: -The conversion of a solid to a liquid is called fusion (or melting). The energy required to melt 1 mol of a substance is its enthalpy of fusion (Hfus). The energy change required to vaporize 1 mol of a substance is the enthalpy of vaporization (Hvap). The direct conversion of a solid to a gas is sublimation.

Detailed explanation-3: -Condensing:The transition from the gas phase to the liquid phase. Sublimination: The transition from the solid phase to the gas phase.

Detailed explanation-4: -Solid to a Liquid One change of state happens when you add energy to the substance. This change of state is called melting. By adding energy to the molecules in a solid the molecules begin to move quicker and can break away from the other molecules.

Detailed explanation-5: -Both temperature and pressure can be measured, and state changes can be observed. When thermal energy is added to a substance, its temperature increases, which can change its state from solid to liquid (melting), liquid to gas (vaporization), or solid to gas (sublimation).