Clarify my lecture notes

[Anonymous No.2940713]

What the fuck.

A) Doesn't this imply that when you pump more gas into a closed vessal the pressure will DECREASE? What the fuck!

B) Also, doesn't this imply that when you compress a gas in a container it will DECREASE the pressure.

[Anonymous No.2940741]

ideal gas law ignores intermolecular interactions

(like charges oppose each other)
(unlike charges attract each other)

with more gas molecules, intermolecular forces are going to have a greater effect than collisions against the wall

A) pressure will decrease very, very marginally
B) compress will decrease very, very marginall

[Anonymous No.2940746]

>>2940713
I'm no chemist. All I can say is, yes, that appears counterintuitive as hell. Am I correct, however, in saying that the note only claims that greater interactions reduce pressure when other variables are equal? For example, if temperature was decreased so that a balloon with more air was to have the same pressure as a balloon with less air, the balloon with more interactions going on would have an even greater loss of pressure than anticipated by temperature alone? Because it's clearly untrue that when you try to pack more air into a balloon it deflates.

[Anonymous No.2940747]

>>2940741
pressure will actually be slightly smaller [from the ideal projections]

excuse my shitty use of language

[Anonymous No.2940767]

>>2940713
No, pressure will still increase in both situations. High concentration of particles means more collision per second. What it means is that it will no longer be proportional, so the ideal gas law will break down.

[Anonymous No.2940786]

>>2940713


http://en.wikipedia.org/wiki/Real_gas


/thread

[Anonymous No.2940814]

>>2940741

you saying that particles with the same charge will repel each other? so if I filled a balloon with oxygen, a negatively charged element, at STP, the pressure would DECREASE because same-charged particles oppose each other?

i'm confused. if i have 100 particles in a closed vessel, and they're all trying to get away from each other, pressure would increase.

otherwise, /looophole

[Anonymous No.2940842]

>>2940814


>so if I filled a balloon with oxygen, a negatively charged element

[Anonymous No.2940870]

>>2940814
>pressure will actually be slightly smaller from the ideal projections

So if I got some + ions in the gas phase, pump them into a balloon that already has other - ions in the gas phase. The actual pressure would be smaller than the projected amount from the ideal gas law.

The ideal gas law says it would be me an X pressure.
But the real gas law is yX pressure, where y is determined from the correction factor.

and so set things straight
oxygen ion is negatively charge
oxygen element is stable

[and in reality they wouldn't always be ions in the gas phase. More commonly they would be molecules with dipoles in the gas phase]

[Anonymous No.2940875]

>>2940814


1) elements (atoms) are neutral

2) elemental oxygen (which means the form it is found naturally) is O2 which is a neutral gas

furthermore

1) O2 is a homodiatomic gas. that means that it is a "non-polar" molecule

(unlike H-Cl, a gas, which is polar due to the difference in electronegativity between its constituent elements)

for future reference: all homodiatomic gases are non-polar (H2, N2, Cl2, F2, I2, Br2, etc)

2) the "real gas" effects with things like oxygen comes from the fact that the electron clouds that surround them can be instantaneously perturbed...

this means that the electrons have moved to a new shape that does not completely "screen" the positively charged nucleus (as it did when the electrons were in their "equilibrium" organization).

this instantaneous reorganization of the charge creates an instaneous dipole (positive and negative charge separated by a small distance).

this effect creates a small force on the surrounding molecules, which results in the same exact thing (the reorganization).


at any given time, all of the molecules in a system have this affect to some degree.


this is called Van der Waals force. it is what makes gasses like Oxygen and Nitrogen capable of becoming liquid at "reasonable" temperatures (molecular weight and non-polar nature would predict significantly lower temperatures, like liquid methane)