🔍 Key Concepts

• Behavior of water when pressure is suddenly changed at high temperature • Relationship between boiling point and pressure in an evaporator • What actually causes flash evaporation in distillation plants

💭 Think About

• Think about what happens to the boiling point of water if you quickly lower the surrounding pressure while the water is already very hot. • Which change (temperature, velocity, density, or pressure) would most directly and immediately cause already-heated water to begin boiling rapidly without adding more heat? • In a distilling plant flash chamber, what condition is different from the feed line: is it temperature, pressure, or something else?

✅ Before You Answer

• Verify how boiling point varies with pressure on a phase diagram of water. • Consider whether velocity alone can change phase without a corresponding change in pressure or temperature. • Ask: in a vacuum-type flash evaporator, which variable is intentionally reduced to cause water to flash into vapor? Focus on pressure vs. temperature.