Question

The substance krypton has the following properties: normal melting point:

normal melting point: 115.9 K
normal boiling point: 119.8 K
triple point; 0.72 atm, 115.8 K
critical point: 54.3 atm, 209.4 K

A sample of krypton is initially at a pressure of 59.8 atm and a temperature of 107.7 K. The pressure on the sample is reduced to 0.720 atm at a constant temperature of 107.7 K. Which of the following are true?

a. The final state of the substance is a solid.
b. One or more phase changes will occur.
c. The final state of the substance is a liquid.
d. The sample is initially a gas.
e. The solid initially present will vaporize.

Answer 1

Part 1

triple point; 0.72 atm, 115.8 K

Part 2

Option D, The sample is initially a gas.

Step-by-step explanation:

Part 1

The triple point of krypton is 0.72 atm

and the melting point of Krypton is -157.4 °C or 115.8 K

Hence, option C is correct

Part 2

Option D

At 59.8 atm, Krypton is a gas. It changes its state from gas to liquid and solid when the temperature is extremely low. Here the temperature is same , hence only option D is correct