Question

The triple point of carbon dioxide (CO₂) occurs at nearly 1,000 times greater pressure, and at a lower temperature, than the triple point of water (H₂O). Based on this information, which of the following statements is true?

A. Increasing the pressure on solid carbon dioxide will result in it melting at constant temperature.
B. Carbon dioxide is found simultaneously in all three phases at a higher temperature and pressure than water
C. The sublimation of water will occur at a higher pressure than the sublimation of carbon dioxide at all temperatures.
D. At the pressure where water is at its triple point, carbon dioxide can only either exist as a solid or a gas:

Answer 1

The correct statement in relation to the triple points of CO₂ and H₂O is that at the pressure where water is at its triple point, CO₂ can only exist as a solid or gas. Option number d is correct.

Step-by-step explanation:

The student's question asks about the triple point of carbon dioxide (CO₂) compared to that of water (H₂O). Based on the provided information, the correct statement is that at the pressure where water is at its triple point, carbon dioxide can only exist as a solid or a gas, as per option D.

The carbon dioxide triple point occurs at a higher pressure and lower temperature compared to water’s triple point. Hence, carbon dioxide requires a pressure of approximately 5.11 atm to reach its triple point where it can exist as a solid, liquid, and gas in equilibrium. In contrast, water only requires 0.00600 atm of pressure to reach its triple point.