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.

Part 1

triple point; 0.72 atm, 115.8 K

Part 2

Option D, The sample is initially a gas.

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

the link still does not work even when adding it to the url bar

explanation:

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.