[Reubend]

Perhaps this is more of a physics question, but I got this question wrong on a chemistry test and was wondering if someone here could explain the correct answer to me. I thought that all three would decrease, but that was not an option.

If an ideal gas was cooled at a constant volume in a container, which of the following values would decrease? 
I. The pressure exerted by the gas on its container 
II. The average distance between gas molecules 
III. The average speed of the gas molecules

[Borek]

Let's start with a different problem.

You have N molecules of gas in a container of volume V. What is the average distance between molecules?

[Reubend]

Let's start with a different problem.

You have N molecules of gas in a container of volume V. What is the average distance between molecules?

I'm not sure, but perhaps something like v/n?

[curiouscat]

I'm not sure, but perhaps something like v/n?

v/n doesn't have dimensions of distance.

[billnotgatez]

Do you think they might of given you a trick question

I got this definition from the internet

Ideal gas  (-dl)
A hypothetical gas whose molecules bounce off each other (and the boundaries of their container) with perfect elasticity and have negligible size, and in which the intermolecular forces acting between molecules not in contact with each other are also negligible. Such a gas would obey the gas laws (such as Charles's law and Boyle's law) exactly at all temperatures and pressures. Most actual gases behave approximately as ideal gases, except at very low temperatures (when the potential energy of their intermolecular forces is high relative to the kinetic energy of the molecules and becomes significant), and under very high pressures (when the molecules are packed so close together that close-range intermolecular forces become significant).

[Borek]

Let's start with a different problem.

You have N molecules of gas in a container of volume V. What is the average distance between molecules?

I'm not sure, but perhaps something like v/n?

As curiouscat pointed out, you are not there yet, but you move in the right direction. Assume each molecule sits in the middle of its own cube.

[curiouscat]

If an ideal gas was cooled at a constant volume in a container, which of the following values would decrease? 
I. The pressure exerted by the gas on its container 

Have you learnt of the Ideal Gas Law yet?

[Reubend]

Let's start with a different problem.

You have N molecules of gas in a container of volume V. What is the average distance between molecules?

I'm not sure, but perhaps something like v/n?

As curiouscat pointed out, you are not there yet, but you move in the right direction. Assume each molecule sits in the middle of its own cube.

If that's where the molecule is, then would it be cbrt(v)/(2n)?

[Borek]

I suppose by cbrt you mean cubic root - you are close, but still not there.

However, you should already see that the distance is a function of V and N only... Now think about the original problem.