4C Change of State# 4C10 PVT Surfaces# pdV Compressing%20a%20gas 4C20 Phase Changes: Liquid-Solid# 4C30 Phase Changes: Liquid-Gas# Boiling%20to%20freeze Dippy%20bird 4C31 Cooling by Evaporation# Evaporating%20ether 4C32 Dew Point and Humidity# 4C33 Vapor Pressure# Boiling%20water%20at%20reduced%20pressure 4C40 Sublimation# 4C45 Phase Changes: Solid - Solid# 4C50 Critical Point#