Equilibrium Question: Can Anyone Help?

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Discussion Overview

The discussion revolves around a question from a textbook concerning a system at equilibrium involving benzene, iodine, and air at 298K. Participants analyze the validity of several statements about the system's behavior at equilibrium, exploring concepts related to chemical equilibrium and phase changes.

Discussion Character

  • Homework-related, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant expresses confusion about the statements regarding the equilibrium state, suggesting that all proposed statements seem untrue based on their understanding.
  • The participant argues that the pressure of the vapor phase should remain constant unless there is a temperature change.
  • They question whether evaporation ceases at equilibrium, suggesting that it does not.
  • Another participant agrees with the initial assessment that at equilibrium, evaporation and condensation rates are equal, implying that statement b) could be true.
  • There is a suggestion that the color of the liquid phase will not change unless there is a change in temperature or pressure, and that the mass of solid iodine should remain constant at saturation.

Areas of Agreement / Disagreement

Participants generally agree on the interpretation that at equilibrium, evaporation and condensation occur at equal rates, but there is no consensus on the validity of the statements provided in the question.

Contextual Notes

The discussion highlights potential misunderstandings about the nature of equilibrium, particularly regarding the continuous processes of evaporation and condensation, and the conditions under which certain properties remain constant.

mister_mister3
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A simple question, it would seem, but I'm missing something..
This is a question in my text.

Q: Consider a stoppered flask containing benzene, iodine, and air, which has reached equilibrium at 298K. Which one of the following statements concerning the system at equilibrium is true?

a) The pressure of the vapour phase is not constant.
b) Evaporation of the liquid continues.
c) The colour of the liquid phase will change.
d) The mass of the solid iodine is not constant.

A: I haven't yet had my text throw me a curveball, but I have found numerous errors which I've confirmed with administrators of the course I'm taking. This one stumps me, which makes me think there's an error. For this one, they all seem untrue. for a), I would think that the pressue of the vapour phase would stay constant unless there were a change in temp. for b) at equilibrium, would evaporation not cease? c) the colour of the liquid will change - obviously not true, since there would have to be a change in temp, or pressure and for d) the iodine would have reached a point of saturation in the benzene at equilibrium, so that couldn't change either...

Can anyone point out what I'm missing? Any help is greatly appreciated!
 
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Write out the balanced equation
 
mister_mister3 said:
A simple question, it would seem, but I'm missing something..
This is a question in my text.

Q: Consider a stoppered flask containing benzene, iodine, and air, which has reached equilibrium at 298K. Which one of the following statements concerning the system at equilibrium is true?

a) The pressure of the vapour phase is not constant.
b) Evaporation of the liquid continues.
c) The colour of the liquid phase will change.
d) The mass of the solid iodine is not constant.

A: I haven't yet had my text throw me a curveball, but I have found numerous errors which I've confirmed with administrators of the course I'm taking. This one stumps me, which makes me think there's an error. For this one, they all seem untrue. for a), I would think that the pressue of the vapour phase would stay constant unless there were a change in temp. for b) at equilibrium, would evaporation not cease? c) the colour of the liquid will change - obviously not true, since there would have to be a change in temp, or pressure and for d) the iodine would have reached a point of saturation in the benzene at equilibrium, so that couldn't change either...

Can anyone point out what I'm missing? Any help is greatly appreciated!

my guess is that B is the only one that is true. at equilibrium, the liquid will keep evaporating and condensing in the container, and the rates of both will be equal.
 
agreed

Thanks,

after spending more time examining the situation, I came to the same conclusion myself. It just required some more thought I suppose.
 

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