When released from a vessel under pressure, butane will:

When released from a vessel under pressure, butane will:

• A. Transition from vapor to liquid
• B. No change
• C. Freeze
• D. Transition from liquid to vapor

Answer: (D)

When a pressurized liquid is released, it tends to flash into gas as the pressure drops to ambient. Butane is stored as a liquid under high pressure, so once the valve is opened, the pressure above the liquid falls. At that lower pressure (and the surrounding temperature), the liquid can no longer stay liquid and boils rapidly, turning into vapor. This rapid liquid-to-gas transition is called vaporization or flashing and it also cools the remaining liquid because energy must be absorbed for the phase change. In short, releasing butane from a pressurized vessel causes it to change from liquid to vapor.

When a pressurized liquid is released, it tends to flash into gas as the pressure drops to ambient. Butane is stored as a liquid under high pressure, so once the valve is opened, the pressure above the liquid falls. At that lower pressure (and the surrounding temperature), the liquid can no longer stay liquid and boils rapidly, turning into vapor. This rapid liquid-to-gas transition is called vaporization or flashing and it also cools the remaining liquid because energy must be absorbed for the phase change. In short, releasing butane from a pressurized vessel causes it to change from liquid to vapor.