Final answer:
The student's question pertains to the behavior of carbon dioxide (CO₂) under different pressures and temperatures, using phase diagrams to understand its state of matter changes. It involves calculations based on gas law equations and understanding of CO₂'s critical and triple points.
Step-by-step explanation:
Understanding Phase Change and Pressure Calculations
The student's question involves concepts from thermodynamics and physical chemistry, specifically dealing with the properties of carbon dioxide (CO₂) in various phases under different temperatures and pressures.
The question references phase diagrams which graphically display the states of a substance under various conditions and implies calculations related to gas laws and phase change principles.
For example, the critical point and triple point are significant in that they represent unique conditions where phases can coexist.
At atmospheric pressure (1 atm), CO₂ cannot exist as a liquid; it sublimes directly from solid to gas at -78.5°C.