❄️ PHASE CHANGE ENTHALPY

PHASE CHANGE

Physical state transition at constant temperature; energy used breaking/forming intermolecular forces, not raising temperature

ENTHALPY OF FUSION (ΔH_fusion)

Heat melting solid → liquid; endothermic, positive; water = 6.01 kJ/mol at 0°C

ENTHALPY OF FREEZING (ΔH_freezing)

Heat liquid → solid; exothermic; ΔH_freezing = −ΔH_fusion

ENTHALPY OF VAPORIZATION (ΔH_vaporization)

Heat liquid → gas; endothermic, positive; water = 40.7 kJ/mol at 100°C

ENTHALPY OF CONDENSATION (ΔH_condensation)

Heat gas → liquid; exothermic; ΔH_condensation = −ΔH_vaporization

ENTHALPY OF SUBLIMATION (ΔH_sublimation)

Heat solid → gas; endothermic

ENTHALPY OF DEPOSITION (ΔH_deposition)

Heat gas → solid; exothermic; ΔH_deposition = −ΔH_sublimation

HEATING CURVE

Temperature vs heat input graph; sloped segments = temperature change; flat segments = phase change at constant T