The key feature of the phase diagram for carbon dioxide is that it includes temperatures and pressure points where the different phases—solid, liquid, and gas—change from one to another. This diagram is essential for understanding how carbon dioxide behaves under various conditions, illustrating critical points, melting points, and sublimation lines.
For carbon dioxide, the phase diagram clearly shows the boundaries between solid, liquid, and gaseous states, making it a valuable tool for predicting how CO2 will behave when subjected to changes in temperature and pressure.
Understanding these phase changes is crucial in many applications, such as dry ice usage, where CO2 transitions directly from solid to gas, a process known as sublimation. This comprehensive approach to depicting the relationships between the phases distinguishes this option as the correct and most informative choice regarding a key feature of carbon dioxide's phase diagram.