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 - 170. °c and 1.0 atm. what will be the state of the sample? suppose the temperature is held constant at - 170. °c but the pressure is decreased by 0.7 atm. what will happen to the sample? suppose, on the other hand, the pressure is held constant at 1.0 atm but the temperature is increased by 355. °c. what will happen to the sample?

Explanation:

Step1: Convert temperature to Kelvin

First, convert - 170°C to Kelvin. The conversion formula is $T(K)=T(^{\circ}C)+273.15$. So, $T=-170 + 273.15=103.15$ K. At 1.0 atm and 103.15 K, from the phase - diagram, the substance is in the solid state.

Step2: Analyze pressure - change

The new pressure is $1.0 - 0.7=0.3$ atm at a temperature of 103.15 K. From the phase - diagram, when the pressure is decreased from 1.0 atm to 0.3 atm at 103.15 K, the substance will sublime (change directly from solid to gas).

Step3: Analyze temperature - change

The new temperature is $-170+355 = 185$°C. Convert it to Kelvin: $T = 185+273.15=458.15$ K. At 1.0 atm and 458.15 K, from the phase - diagram, the substance is in the liquid state, so it will melt (change from solid to liquid).

Answer:

Solid
It will sublime
It will melt