Homework Help

A gas changes directly into a solid. How does this change affect energy?A. energy is...

user profile pic

hellopow | Student, Grade 10 | eNotes Newbie

Posted August 19, 2012 at 11:07 PM via web

dislike 1 like

A gas changes directly into a solid. How does this change affect energy?

A. energy is released into the surroundings

B. energy is absorbed by the solid

C. energy of the solid increases

D. energy of the surroundings decreases

1 Answer | Add Yours

user profile pic

llltkl | College Teacher | (Level 3) Valedictorian

Posted August 22, 2012 at 8:16 AM (Answer #1)

dislike 1 like

A. energy is released into the surroundings

When a gas changes directly into a solid the process is known as deposition. We know during phase transition at a fixed temperature, certain amount of heat transfer takes place, this is called latent heat of transition. The direction of this heat transfer can be understood easily by considering the interparticle distance in three phases. In gas phase interparticle distance is quite large, moderate in liquid phase and lowest in solid phase. In the given example the phase change involves transition from gaseous phase to solid phase directly. That means interparticle distance must be reduced, or the molecules/particles have to be brought closer. Only way to do this is by lowering the energy of the molecules. So this involves extraction of heat from the system and releasing it into the surroundings.

Join to answer this question

Join a community of thousands of dedicated teachers and students.

Join eNotes