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# Volume and Temperature Watch

1. As temperature increases, why does volume increase (at a constant pressure)?

Is it because the particles have more K.E. energy thus they collide harder and more

Thanks!
2. I think it's because Pressure is the Force per unit Area, so yeah as you said when the temperature increases the particles convert more heat energy into kinetic energy and exert a larger force on the walls of the container, meaning for the pressure to remain constant the area, and therefore the volume, over which the force is exerted must increase.

(sorry if this isn't written very well, my brain doesn't really function at this time)
3. The equation to link it is: PV = nRT. Temperature and volume are proportional.

Kinetic energy is probably the main reason. If you raise the temperature, the particles become more excited and move more... They have a larger vibration and occupy a larger area of space. If the pressure is constant, that means the have nothing to do other than act with more force against the boundaries of the container. If the pressure was not constant, the pressure would decrease (as per the equation) to maintain the balance.
4. (Original post by SillyEddy)
The equation to link it is: PV = nRT. Temperature and volume are proportional.

Kinetic energy is probably the main reason. If you raise the temperature, the particles become more excited and move more... They have a larger vibration and occupy a larger area of space. If the pressure is constant, that means the have nothing to do other than act with more force against the boundaries of the container. If the pressure was not constant, the pressure would decrease (as per the equation) to maintain the balance.

Thanks so much! - You really helped!

One question though - so with more K.E energy the particles are spread out more ("occupy a larger area of space"), therefore does this mean that the frequency of particles colliding with the walls of the container, that it's in, will decrease- but this is compensated by the point that the particles will exert a larger force each time? (hits harder but less).
5. (Original post by 11flon)
I think it's because Pressure is the Force per unit Area, so yeah as you said when the temperature increases the particles convert more heat energy into kinetic energy and exert a larger force on the walls of the container, meaning for the pressure to remain constant the area, and therefore the volume, over which the force is exerted must increase.

(sorry if this isn't written very well, my brain doesn't really function at this time)

Thanks so much! - You really helped!
6. (Original post by park1996)
Thanks so much! - You really helped!

One question though - so with more K.E energy the particles are spread out more ("occupy a larger area of space"), therefore does this mean that the frequency of particles colliding with the walls of the container, that it's in, will decrease- but this is compensated by the point that the particles will exert a larger force each time? (hits harder but less).
I'm not quite sure of an equation which could prove or disprove that, so I can't give an absolute answer.

For an ideal gas, we usually expect there to be a perfectly elastic collision... That is to say, it will bounce off the wall with the same momentum that it had before the collision. I think I may have been slightly misleading with the idea that it vibrates about a point (like an electron or solid atoms might). It would likely bounce off and then hit another surface. Because it has more K.E, it has more velocity (K.E = mv^2 and the mass probably has not changed, so the velocity must increase) and so it will have a larger "collision frequency" with other surfaces. It can travel further, so hit more things more often. Because it occupies a larger space, it will probably hit other particles more frequently and push them out. That is why there is a net volume increase, because all the atoms are moving faster and hitting more things more often.

But I don't have a way to really prove that mathematically. Or I might, but I'm a student who has been drinking - That's a principle you can apply to lecturer and tutors when you're 18+ or go to university!

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