A phase diagram of CO₂ shows the triple point at (5.1 atm, −56.6 °C).
At 1.0 atm and warming from −80 °C, what phase change(s) occur?
- A
Liquid forms and stays liquid.
- B
Solid stays solid.
- C
Solid melts to liquid then boils.
- Dcheck_circle
Solid sublimes directly to gas (no liquid).
Explanation
At 1.0 atm (below triple-point pressure 5.1 atm), CO₂ skips the liquid phase: solid sublimes directly to gas.