Shown here is textbook Figure 11.24 with a phase diagram for pure carbon dioxide

Question

Shown here is textbook Figure 11.24 with a phase diagram for pure carbon dioxide (with a discontinuity in the pressure axis). Consider a sample of carbon dioxide held at a pressure of 600 kPa. Describe what changes of state will occur if the temperature is initially increased from -100 degree C to 0 degree C, and then while maintaining the temperature at 0 degree C the pressure is increased to 7390 kPa? Determine the number of phases present at a pressure of 518 kPa and -56.6 degree C. Imagine you have a sealed cell with a window through which you observe both liquid and gaseous carbon dioxide in equilibrium. Write down the range of combined temperature and pressure for which this observation is i.e. (p_lower, T_lower) rightarrow (P_upper, T_upper) Following on, describe what changes you observe in your cell if you increase both the temperature and pressure above the upper bounds.

Explanation / Answer

part a

from the diagram it is evident that at 600 kpa and -100 C

so it moves initially from solid to liquid phase and then at 0 C it end up in vapor phase

part b

at this point all the three lines meet it is a unique point which is called tripple point where all the 3 states coexist.

part c

when you move away from the critical point vapor phase would be lost

so the bottom limit is (518 Kpa, -66.6 C)

ant the top limit is (7390 kpa, 31 C)

part d

if you increase the temperature above the upper limits it will enter into supercritical region where it is not possible to differentiate between liquid and gas phase because the interface between them dissapears and that specilality of superciritcal fluids.

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.