Below is a phase diagram for compound Q.You wish to purify a sample of Q that was collected at P = 1.0 atm and T = 100 K by subliming it.In order to sublime the sample,you should:
A)Increase P to 1.5 atm and then increase T to 300 K.
B)Increase T to 300 K,keeping P = 1.0 atm.
C)Lower P to 0.5 atm and then increase T to 200 K.
D)Increase T to 300 K and then lower P to 0.5 atm.
E)Abandon the attempt to sublime Q.

Question

Below is a phase diagram for compound Q.You wish to purify a sample of Q that was collected at P = 1.0 atm and T = 100 K by subliming it.In order to sublime the sample,you should: 
A)Increase P to 1.5 atm and then increase T to 300 K. 
B)Increase T to 300 K,keeping P = 1.0 atm. 
C)Lower P to 0.5 atm and then increase T to 200 K. 
D)Increase T to 300 K and then lower P to 0.5 atm. 
E)Abandon the attempt to sublime Q.

Quizplus · Accepted Answer

According to the phase diagram, at 1 atm and 100 K, compound Q is in the solid phase. To sublime it, we need to increase the temperature and decrease the pressure to get to the vapor phase. Option C lowers the pressure to 0.5 atm and then increases the temperature to 200 K, which puts us in the vapor phase. Option A would take us to the liquid phase, and options B and D would not decrease the pressure enough to reach the vapor phase. Therefore, option C is the best choice for subliming compound Q.

Below Is a Phase Diagram for Compound Q