consider this phase diagram for carbon dioxide

consider this phase diagram for carbon dioxide

Consider this phase diagram for carbon dioxide. In what phase is CO_2 at 25 atm and -65 degree C? solid gas liquid Starting from the point described above, what phase change would eventually result from a decrease in pressure? freezing vaporization condensation deposition melting sublimation

The Correct Answer and Explanation is :

At 25 atm and -65°C on the CO₂ phase diagram, carbon dioxide is in the solid phase. To determine this, you would reference the triple point and critical point on the diagram. The triple point of CO₂ is around 5.1 atm and -56.6°C, where solid, liquid, and gas phases coexist. Given the conditions (25 atm and -65°C), they are above the triple point pressure but below the triple point temperature, which places the substance in the solid phase.

If you decrease the pressure from this point, the phase change that would occur is sublimation. Sublimation is the transition of a substance directly from the solid to the gas phase without passing through an intermediate liquid phase. In the phase diagram, lowering the pressure while keeping the temperature constant at -65°C would move the state of CO₂ from the solid region, crossing the sublimation curve before reaching any other phase boundary, thereby turning directly into gas.

This explanation relies on understanding the relationships and boundaries depicted in phase diagrams, which graphically represent the phases of a substance under varying temperatures and pressures. The critical point and triple point are crucial for understanding the behavior of CO₂ under different conditions, as they mark the unique states where phases coexist or change dramatically.

As for generating the image of the phase diagram, I am unable to directly access the image from the URL you provided due to technical restrictions. However, if you need an illustration of a CO₂ phase diagram, I could help describe one or find a similar image online if that helps!