Question 13 from the ACS chemistry olympiad exam:

The phase transition from gas to solid is called \begin{align} &\text{(A) condensation.} & \text{(B) evaporation.} \\ &\text{(C) polymerization.} & \text{(D) sublimation.} \end{align}

I am pretty sure the answer is deposition, which is not listed, but yet the answer is (A) condensation [scroll to the end of the question paper to see the answer key].

Did the chemistry olympiad make a mistake, or is there something obvious that I am missing?


1 Answer 1


I guess the diagram of phase changes you have in mind looks like this:

enter image description here

Indeed this says deposition is the right name for a gas-to-solid phase transition and I believe that this is the only correct term.

The only thing I can argue why it is obvious here that condensation is the right answer (at least the closest) is that this is the only answer that gives a transition from fluid to solid. B and D are the other way around, and C is not really a phase change (although it could result in one).

  • 1
    $\begingroup$ Good point concerning the condensation as the only "real" phase change in a classical sense. $\endgroup$ Mar 17, 2014 at 8:04

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.