Volume vs temp vs pressure question

In summary, according to the expert, increasing the pressure does not necessarily mean increasing the volume of the gas, but it could if the gas is in an "ideal gas" state. Increasing the temperature does increase the volume of the gas, as long as the gas is in an "ideal gas" state.
  • #1
Rusho
24
0
So here is the question:
I have a gas contained in a volume(like a sealed can). If I increase the temperature does the volume stay the same?
If I increase the pressure, does the volume stay the same?

It seems like it would, but I think volume is confused with "quantity", which I can see changing in all of the above circumstances.

Thx for any help
 
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  • #2
If you have a sealed can(none of the gas can escape) you will not see an increase in volume. I think you acn see why. If you approximate this general gas as an Ideal gas, obeying the equation of state PV=nRT, you see that if you increase the temperature in a constant volume process that the pressure must also increase (by looking at the equation PV=nRT, where V,n,R all constant)
Cheers,
Norm
 
  • #3
Originally posted by Rusho

It seems like it would, but I think volume is confused with "quantity", which I can see changing in all of the above circumstances.

How is the quantity changing if you've got a sealed can?
 
  • #4
hmmm.
Well if a person can pack more pressure in, then more molecules are entering, so more "quantity", but the volume is the same. So its more dense?
 
  • #5
I think you are confused with what is meant by pressure. Pressure is force per unit area (F/A), so increasing the pressure does not mean increasing the number of molecules (n). It means that the force imparted on the surface has increased. You can think of this is each molecule having more momentum so when it bounces off the container, its change in momentum is greater thus making a larger force (per Newton's second law). Does that make more sense (or any at all)?
good luck,
Norm
 
  • #6
Yes, I understand.
Thx!
 
  • #7
The "ideal gas law" is PV= NRT.

T is the temperature (in degrees Kelvin), P is the pressure, V is volume, N the number of molecules (or mols depending on how R is taken) and R is "Boltzmann's constant". If you take a "sealed" can (so that no molecules can get in or out) then N stays the same. You can increase pressure, P, by increasing T (heat the can) while V stays constant or by decreasing V (imagine one end of the can as a plunger that can be pushed down into the can) while T remains the same (you will have to push the plunger down slowly, allowing any increase in temperature due to the energy exerted to "bleed off" to the environment around the can.
 
  • #8
I have an, only peripherally, related question.

Given a container with a gas, assuming a constant internal/external pressure differential, with a hole of a particular diameter/area, what is formula to compute the rate at which the gas exits the hole.

Assume we're talking ideal gas or air and anything else that I haven't given, but are needed.
 
  • #9
(P1T1)/V1=(P2T2)/V2

Nautica
 
  • #10
temp vs. Pressure

Hi All,

I like some of the answers and the direction that this discussion is headed, but let's add one more varible to the equation, that is needed for liquids in sealed containers:
" Coefficient of Expansion for Liquids and Gases"

Now, with this in mind let's think another variable related to expansion of liquids and gases in a liquid state within a sealed container ,,,, say an aerosol can filled to the top;

Electrons + heat > Coefficent of Expansion > Possible Hydraulic pressure or vapor Pressure
 
  • #11
You are 3 years too late. The ship has left the harbor.

You might want to pay attention to the DATE of the thread and the last post.

Zz.
 

What is the relationship between volume, temperature, and pressure?

The relationship between volume, temperature, and pressure is known as the Ideal Gas Law, which states that the product of the pressure and volume of a gas is directly proportional to the temperature of the gas and the number of moles of gas present, at a constant pressure.

How does temperature affect volume and pressure?

As temperature increases, the volume of a gas also increases, while the pressure decreases. This is because the gas particles gain more kinetic energy at higher temperatures, causing them to move faster and spread out, resulting in an increase in volume. At the same time, the increased kinetic energy also causes the particles to collide with the container walls less frequently, resulting in a decrease in pressure.

What happens to the volume and pressure of a gas when it is heated?

When a gas is heated, the volume of the gas increases while the pressure decreases. This is because the increased temperature causes the gas particles to gain more kinetic energy and move faster, resulting in an increase in volume. At the same time, the increased kinetic energy also causes the particles to collide with the container walls less frequently, resulting in a decrease in pressure.

How does changing the volume of a gas affect its temperature and pressure?

If the volume of a gas is decreased, the temperature of the gas will increase while the pressure remains constant. This is known as Charles's Law, which states that at a constant pressure, the volume of a gas is directly proportional to its temperature. Similarly, if the volume of a gas is increased, the temperature will decrease while the pressure remains constant.

What is the difference between volume, temperature, and pressure in a gas and a liquid?

In a gas, the volume and pressure are directly proportional, meaning that as one increases, the other also increases. In a liquid, however, the volume and pressure are not directly proportional, as liquids are not compressible like gases. Temperature affects both gases and liquids, but in a gas, an increase in temperature results in an increase in volume and a decrease in pressure, while in a liquid, an increase in temperature results in an increase in volume and an increase in pressure.

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