Exploring Ionized Air and its Effects on Gas Molecules

In summary, The conversation is discussing the behavior of ionized gas, specifically ionized air, and how it differs from non-ionized gas. The main question is whether the gas molecules maintain the same root mean square (rms) speed after being ionized. The conversation also touches on the potential production of ions and the effect of collisions with neutral molecules. It is mentioned that the ions may have a higher rms speed due to their positive charge and the equation Vrms = sqrt(3RT/M) is referenced, indicating that as temperature increases, so does the rms speed of gas molecules.
  • #1
Dburghoff
16
0
I'm trying to do some thought experiments involving ionized gas. More specifically, I'm thinking about ionized air. For the sake of argument, let's just imagine that we're ionizing the air by sticking a pin out of a Van de Graaff generator that's positively charged.

My main question is this: how do the gas molecules actually behave? Do they keep the same rms speed as their non-ionized counterparts? The moment that they're ionized by the needle, I'd imagine that they're accelerated in all directions (except for towards the VDG generator), as they are repelling one another, so would this change its rms speed? Overall, I'm very confused over the whole subject.
 
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  • #2
I do not know if some help in terms of ionic production (positve or negative )would help here? A interesting question though when considering the potent smell(ozone) before electrical spark generation :smile:

Maybe a condensive feature from such a spark leaves telling tales about the nature of that enviroment?
 
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  • #3
I don't really care about ionic production here. If you want to think of it as being produced by an X-ray, that's fine by me. I'm more interested in how the gas behaves after it's been ionized. Thanks anyway, though.
 
  • #4
A neutral molecule of air gets close enough to the needle that one or more of the electrons are stolen by the needle at which point that air molecule has a positive charge. The positive ion would then be repelled by the positive field from the Van de Graaff.
 
  • #5
Right, but I'm trying to consider how the gas as a whole behaves. The movement of individual air molecules will most likely be slowed by the neutral molecules that it slams into along the way. So, will the rms speed of all of the charged molecules remain about the same as the uncharged ones?
 
  • #6
My intuition says the ions will be faster on average--possibly fast enough to create additional ions from some of their early collisions with neutral molecules. Once an ion is moving slowly enough to be likely to regain neutrality from its collisions with oppositely-charged particles, it won't take long, on average, for it to fall back to essentially the same speed as the neutral molecules. But that's just my intuition.
 
  • #7
Vrms = sqrt(3RT/M)
This is an equation commonly used to find the root mean square velocity of gases. From what i see...the speed must be much much faster. It's common knowlegde for all of us here that ionized gas is very hot, therefore, its moving fast. From the equation its clear that as T(temp.) increases, so does the rms of the gas. Well that's how i see it :)
 
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1. What is ionized air?

Ionized air is air that has been electrically charged, resulting in the creation of ions. These ions are atoms or molecules that have gained or lost electrons, giving them a positive or negative charge.

2. How is air ionized?

Air can be ionized through various methods such as exposure to high-voltage electric fields, ultraviolet radiation, or radioactive materials. Lightning strikes and other natural phenomena can also ionize the air.

3. What are the effects of ionized air on gas molecules?

Ionized air can cause gas molecules to become energized and move more rapidly, leading to an increase in temperature. It can also cause the molecules to become more reactive and form new compounds.

4. How is ionized air used in scientific research?

Ionized air is used in various scientific research fields, such as atmospheric chemistry, materials science, and plasma physics. It can be used to study the behavior of gas molecules and their interactions with other substances.

5. Are there any potential health concerns associated with exposure to ionized air?

There have been some studies that suggest prolonged exposure to high levels of ionized air may have negative health effects, such as respiratory problems. However, more research is needed to fully understand the potential risks of ionized air on human health.

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