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 36. °c and 1.9 atm. what will be the state of the sample? select suppose the temperature is held constant at 36. °c but the pressure is decreased by 1 atm. what will happen to the sample? select suppose, on the other hand, the pressure is held constant at 1.9 atm but the temperature is decreased by 70. °c. what will happen to the sample? select

Explanation:

First Sub - Question: Determine the state at 36°C and 1.9 atm

Step 1: Convert temperature to Kelvin

The formula to convert Celsius to Kelvin is $T(K)=T(^{\circ}C) + 273.15$. For $T = 36^{\circ}C$, we have $T(K)=36 + 273.15=309.15\ K$.

Step 2: Analyze the phase diagram

Looking at the phase diagram, at a temperature of approximately 309 K (36°C) and a pressure of 1.9 atm, we check the regions. The pressure of 1.9 atm and temperature ~309 K falls in the "liquid" region of the phase diagram (since the liquid region is between the solid - liquid and liquid - gas curves at this pressure - temperature range).

Second Sub - Question: Pressure decreased by 1 atm at constant 36°C (309 K)

Step 1: Calculate the new pressure

The initial pressure is 1.9 atm. After decreasing by 1 atm, the new pressure $P = 1.9- 1=0.9\ atm$.

Step 2: Analyze the phase change

At a constant temperature of 309 K, when the pressure decreases from 1.9 atm to 0.9 atm, we move from the liquid region to the gas region (by crossing the liquid - gas boundary curve in the phase diagram). So the liquid will vaporize (boil) to form gas.

Third Sub - Question: Temperature decreased by 70°C at constant 1.9 atm

Step 1: Calculate the new temperature

The initial temperature is 36°C. After decreasing by 70°C, the new temperature $T(^{\circ}C)=36 - 70=- 34^{\circ}C$. Convert this to Kelvin: $T(K)=-34 + 273.15 = 239.15\ K$.

Step 2: Analyze the phase change

At a constant pressure of 1.9 atm, when the temperature decreases from 309 K to 239 K, we move from the liquid region to the solid region (by crossing the solid - liquid boundary curve in the phase diagram). So the liquid will freeze to form a solid.

Answer:

s:

1. For the first sub - question: The state of the sample is liquid.
2. For the second sub - question: The sample will vaporize (boil) (liquid→gas).
3. For the third sub - question: The sample will freeze (liquid→solid).