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 - 123. °c and 1.1 atm. what will be the state of the sample? suppose the temperature is held constant at - 123. °c but the pressure is decreased by 0.4 atm. what will happen to the sample? suppose, on the other hand, the pressure is held constant at 1.1 atm but the temperature is increased by 175. °c. what will happen to the sample?

Explanation:

Step1: Convert temperature to Kelvin

First, convert - 123°C to Kelvin. The conversion formula is $T(K)=T(^{\circ}C)+273.15$. So, $T = - 123+273.15=150.15$ K. At 150.15 K and 1.1 atm, from the phase - diagram, the substance is in the solid phase.

Step2: Calculate new pressure

The new pressure when decreased by 0.4 atm is $P = 1.1 - 0.4=0.7$ atm. At a temperature of 150.15 K and 0.7 atm, the substance changes from solid to gas (sublimation).

Step3: Calculate new temperature

The new temperature when increased by 175°C from - 123°C is $T=-123 + 175=52$°C. Convert 52°C to Kelvin: $T = 52+273.15 = 325.15$ K. At 325.15 K and 1.1 atm, the substance changes from solid to liquid (melting).

Answer:

Solid
It will sublime (change from solid to gas)
It will melt (change from solid to liquid)