[vissh]

Greetings first of all Got a few multiple correct options type questions in which i need help  . Will be thankful for the answers  .
1)At constant volume for a fixed number of moles of a gas,pressure of gas increases with rise of temperature due to :
(a)increase in average molecular speed
(b)increased rate of collisions amongst molecules
(c)increase in molecular attraction
(d)decrease in mean free path
[-- As much i know (a)[increase in change of momentum] is correct .but think that some of the other options are also correct . Can u tell me which ones and why??--]

2)Which of following are wrong?
(a)Kinetic energy[K.E.] of a gas depends on its mass.
(b)K.E. of a gas depends on volume[V]
(c)K.e. of a gas depends on pressure[P]
[-- As i know K.E. depends on temperature and temperature is directly related to P and V.Does this means that (b)(c)are correct? --]

3)Can the gases with compressibility factor,Z>1[like He]and ideal gases be liquefied at some pressure and temperature?

[Jorriss]

Greetings first of all Got a few multiple correct options type questions in which i need help  . Will be thankful for the answers  .
1)At constant volume for a fixed number of moles of a gas,pressure of gas increases with rise of temperature due to :
(a)increase in average molecular speed
(b)increased rate of collisions amongst molecules
(c)increase in molecular attraction
(d)decrease in mean free path
[-- As much i know (a)[increase in change of momentum] is correct .but think that some of the other options are also correct . Can u tell me which ones and why??--]

So we can agree (a) is correct, let's think the others through.

b) Pressure is gas molecules beating up the sides of the container, so even though the particles will collide with eachother more often, does that have an effect on the pressure they are exerting on their container?

c) If you increase temperature, on average, each particle has more energy. Are intermolecular forces more or less significant with more energy?

d) Think of b, mean free path may be affected (who knows I'm not a magician?), but does it affect pressure even so?

2)Which of following are wrong?
(a)Kinetic energy[K.E.] of a gas depends on its mass.
(b)K.E. of a gas depends on volume[V]
(c)K.e. of a gas depends on pressure[P]
[-- As i know K.E. depends on temperature and temperature is directly related to P and V.Does this means that (b)(c)are correct? --]

I would have thought b and c are wrong myself.
Let's look at a formula for kinetic energy,

KE = (1/2)mv^2

We see kinetic energy does depend on mass and, even though temperature and pressure or volume are proportional, (b) and (c) do not mention temperature at all, so I don't think I consider those two factors in kinetic energy so explicitly. I'd say those two are wrong.

3)Can the gases with compressibility factor,Z>1[like He]and ideal gases be liquefied at some pressure and temperature?

Yeah, if you look at their phase diagrams, you'll see there are spots where Helium can be a liquid and, even though it's hard to make, there is liquid helium.

[vissh]

Thanks Jorriss  So pressure of gas molecules doesn't depend on the rate of collision and also not on mean free path (rite!!).