gases passage tbr 2

[echoyjeff222]

14. A gas differs from a liquid in all of the following ways
EXCEPT:
A. a liquid has a definite volume while a gas does not.
B. particles in a liquid are always in contact with one
another, while particles in a gas are never in contact
with one another.
C. a gas is more compressible than a liquid.
D. an object is more buoyant in a gas than a liquid.

Okay so I thought B was wrong because of the part with "NEVER in contact with one another" which is just flat out wrong. The gas particles do collide with one another?? Or does the kinetic theory just treat the gas particles as nonexistant (no volume) and therefore they don't touch each other at all?

Also the question wasn't very clear about whether this was for real or ideal gases >.>

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[NextStepTutor_1]

While it is true that a real gas' atoms/compounds WILL have occasional contact with each other because they occupy some volume and are not static above absolute zero, for the MCAT it is generally safe to assume that every time gases are referenced that they satisfy ideal gas conditions (i.e. no mass, no volume, and all collisions are perfectly elastic), UNLESS otherwise stated.

As an aside - an atoms' or compounds' attraction or repulsion as a gas will have major consequences on the pressure of the system. If there is attraction, a negative deviation from ideal pressure will be seen because there are less molecules colliding with the walls of the container. If there is repulsion, a positive deviation from ideal pressure will be seen because there are more molecules colliding with the container walls.





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