In: Chemistry
A. Normal conditions of temperature and pressure are \(25^{\circ} \mathrm{C}\) and \(1.01\) bar pressure. From the phase diagram of \(\mathrm{CO}_{2}\), the area at the intersection of \(25^{\circ} \mathrm{C}\) and \(1.01\) bar pressure comes under gaseous phase. So \(\mathrm{CO}_{2}\) is a gas.
B. Pr essure of \(1 \mathrm{~atm}=1.01\) bar. The pressure of \(1.01\) bar is below the triple point of the phase diagram. So there is no temperature at which the liquid phase exists.
C. All three phases exist simultaneously at the triple point. This is the definition of the triple point.
D. \(\mathrm{CO}_{2}\) forms a supercritical fluid above the temperature of \(31^{\circ} \mathrm{C}\). So this statement is false.
\(\mathrm{E}\). When the pressure is \(4 \mathrm{~atm}\) and temperature is more than \(-56.7 \mathrm{C}\), the phase diagram indicates a gaseous state. So this statement is false.
F. A boundary line indicates the differnce between two phases. So movement across a boundary line corresponds to a phase change.
So \(\mathrm{A}, \mathrm{B}, \mathrm{C}\), and \(\mathrm{F}\) are true statements.