Dec 26, 2019
34
26
Status
  1. Pre-Medical
Passage:

The NH3 gas produced was delivered through a rubber hose to fill a dry inverted 12-oz aluminum soft-drink can by downward displacement of air. The can was then sealed with parafilm and placed sealed side down in a shallow tray containing an inch of water. The seal was then removed. As the NH3 rapidly dissolved in the water, the atmospheric pressure crushed the can.


Question: If methane (CH4) were substituted for NH3 in the aluminum can, the crushing of the can would:

  • A.occur because CH4, being polar, would dissolve in the water in the tray.
  • B.occur because CH4, being nonpolar, would dissolve in the water in the tray.
  • C.not occur because CH4, being polar, would not dissolve in the water in the tray.
  • D.not occur because CH4, being nonpolar, would not dissolve in the water in the tray.

I understand why D is the answer because CH4 is nonpolar and water is polar so CH4 won't dissolve in the water. I don't understand aamc's explanation that "Since the CH4 will remain in the gas phase, the can will not be crushed by the formation of a vacuum inside the can."

Why will CH4 remain in the gas phase?
 
Feb 5, 2020
404
267
Status
  1. Medical Student (Accepted)
CH4 is colloquially called methane, which is part of natural gas and one of the main greenhouse gases contributing to climate change. Also, the question assumes they’re adding methane gas instead of ammonia gas. Just read the options and pick the answer that makes the most sense, which leaves you with D based on simple like-dissolve-like principle and polarity of methane.
 

Your message may be considered spam for the following reasons:

  1. Your new thread title is very short, and likely is unhelpful.
  2. Your reply is very short and likely does not add anything to the thread.
  3. Your reply is very long and likely does not add anything to the thread.
  4. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
  5. Your message is mostly quotes or spoilers.
  6. Your reply has occurred very quickly after a previous reply and likely does not add anything to the thread.
  7. This thread is locked.
About the Ads