Understanding Phase Diagrams
A phase diagram shows the different states of matter (solid, liquid, gas) a substance can exist in under varying conditions of temperature and pressure.
* Temperature is plotted on the x-axis.
* Pressure is plotted on the y-axis.
The diagram is divided into regions representing the different phases. Lines on the diagram indicate the conditions where two phases are in equilibrium.
Finding the State of CO2
1. Locate the Temperature: Find -20°C on the temperature axis of the CO2 phase diagram.
2. Locate the Pressure: Find 1 atm on the pressure axis.
3. Find the Intersection: Draw imaginary lines from -20°C on the temperature axis and 1 atm on the pressure axis. The point where these lines intersect will be the state of CO2 at those conditions.
The Result
You'll find that -20°C and 1 atm fall within the solid phase region of the CO2 phase diagram. This means carbon dioxide will be in a solid state (dry ice) at these conditions.
Important Note: You need an actual CO2 phase diagram to perform this exercise. You can find one easily with a quick search online.
