Question

study the following phase diagram of substance x. use this diagram to answer the following questions. suppose a small sample of pure x is held at - 75. °c and 1.4 atm. what will be the state of the sample? suppose the temperature is held constant at - 75. °c but the pressure is decreased by 1.1 atm. what will happen to the sample? suppose, on the other hand, the pressure is held constant at 1.4 atm but the temperature is decreased by 149. °c. what will happen to the sample?

Explanation:

Step1: Convert temperature to Kelvin

$-75^{\circ}C=( - 75 + 273.15)K=198.15K$. Locate the point $(198.15K, 1.4atm)$ on the phase - diagram. It is in the liquid region.

Step2: Calculate new pressure

The new pressure is $1.4atm - 1.1atm = 0.3atm$. Locate the point $(198.15K,0.3atm)$ on the phase - diagram. Starting from the liquid state at $(198.15K,1.4atm)$ and moving to $(198.15K,0.3atm)$, the substance changes from liquid to gas (vaporization).

Step3: Calculate new temperature

The new temperature is $-75^{\circ}C-149^{\circ}C=-224^{\circ}C$. Convert to Kelvin: $(-224 + 273.15)K = 49.15K$. Locate the point $(49.15K,1.4atm)$ on the phase - diagram. Starting from the liquid state at $(198.15K,1.4atm)$ and moving to $(49.15K,1.4atm)$, the substance changes from liquid to solid (freezing).

Answer:

Liquid
It will vaporize.
It will freeze.