Does 1 mole of all gas exert equal pressure

In summary, the ideal gas law states that at the same temperature and pressure, equal volumes of different gases contain an equal number of molecules. This means that when considering ideal gases, the pressure exerted by 1 mole of molecules on the wall of a container will be the same for all gases, regardless of their sizes. This is because the effects of molecular size, speed, and mass all compensate for each other, resulting in pressure being independent of the molecular mass. However, for real gases, the Van der Waal and Beattie Bridgeman equations should be considered for higher accuracy.
  • #1
rajeshmarndi
319
0
1 mole of all gas has equal number of molecules irrespective of their size. So I just wanted to know when 1 mole of molecules exerts pressure on the wall of a container, will it be same for all gases, irrespective of their molecules sizes.
 
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  • #2
When we consider them as ideal gases, it is when all the other factors like Volume and temperature are the same.
(pV = nRT)
 
  • #3
Avaron Cooper said:
When we consider them as ideal gases, it is when all the other factors like Volume and temperature are the same.
(pV = nRT)
Isn't it is the external atmospheric condition of the room where the experiment is carried.

Also like you say, when the ideal gas possesses equal volume, temperature, pressure and number of molecules. Isn't the molecules whose sizes are bigger and when equal number of that molecules hit the wall of the container, per unit area, will result increase in pressure, than molecules smaller in size.
 
  • #4
rajeshmarndi said:
Isn't it is the external atmospheric condition of the room where the experiment is carried.

Also like you say, when the ideal gas possesses equal volume, temperature, pressure and number of molecules. Isn't the molecules whose sizes are bigger and when equal number of that molecules hit the wall of the container, per unit area, will result increase in pressure, than molecules smaller in size.
According to Avogardro's law, at the same temperature and pressure, equal volumes of different gases contain equal number of molecules. So if we apply this to pV= nRT, pressure also becomes equal.
 
  • #5
rajeshmarndi said:
Isn't it is the external atmospheric condition of the room where the experiment is carried.

Also like you say, when the ideal gas possesses equal volume, temperature, pressure and number of molecules. Isn't the molecules whose sizes are bigger and when equal number of that molecules hit the wall of the container, per unit area, will result increase in pressure, than molecules smaller in size.
You forget that they are bigger but slower. The average speed is inverse proportional to the square root of molecular mass.
This will also have an effect on the number of molecules hitting the wall in a give time. It is less for more massive molecules.
All the effects compensate for ideal gas so that the pressure is independent of the molecular mass.
 
  • #6
nasu said:
You forget that they are bigger but slower. The average speed is inverse proportional to the square root of molecular mass.
This will also have an effect on the number of molecules hitting the wall in a give time. It is less for more massive molecules.
All the effects compensate for ideal gas so that the pressure is independent of the molecular mass.
Thanks I understood it, now. There should be some factor which compensate the impacting of the bigger size molecules, which were equal in number as other sizes molecules, hitting equally in number the wall per unit area and producing the equal pressure.
 
  • #7
If you're willing to sift through some sludge, it would be worth googling for "ideal gas law deviation".

##PV=nRT## precisely describes the behavior of a hypothetical ideal gas. Real gases don't behave quite exactly the same way, although they come so close that we can generally use the ideal gas law and ignore the deviations (which are caused by the stuff that's being discussed above, and more). The google search I suggest will find much interesting discussion of these deviations.
 
  • #8
Van der waal equation for gases modifies the ideal gas law to account for both molecular size and intermolecular attraction. If you need high accuracy, read up on Beattie Bridgeman equation of state. I played with it in excel, and there are indeed quite interesting differences compared to the ideal gas law, especially at extreme pressures and/or temperatures.
 
  • #9
For an ideal gas, where you can neglect particle-particle collisions and particle rotation the following holds.
Equal temperature means equal kinetic energy, so heavier molecules go slower. The number of collisions with the wall per unit time is proportional to v and the imparted momentum per collision is 2mv. Thus the imparted momentum to the wall per unit time, the force, is proportional to 2mv^2, that is proportional to the kinetic energy, that is to T. The exerted on the walls of the volume is therefore independent of the mass.
 

1. What is a mole of gas?

A mole is a unit of measurement used in chemistry to represent a specific number of particles, where 1 mole is equal to 6.022 x 10^23 particles. In the case of gas, 1 mole represents 6.022 x 10^23 molecules or atoms of that gas.

2. Does 1 mole of all gas exert equal pressure?

No, 1 mole of gas does not exert equal pressure. The pressure of a gas depends on its volume, temperature, and number of particles. However, at the same temperature and volume, 1 mole of any ideal gas will exert the same pressure.

3. What is the ideal gas law?

The ideal gas law is a mathematical equation that describes the relationship between the pressure, volume, temperature, and number of moles of an ideal gas. It is expressed as PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the gas constant, and T is temperature in Kelvin.

4. How is the pressure of a gas related to the number of moles?

The pressure of a gas is directly proportional to the number of moles, assuming all other factors such as volume and temperature remain constant. This means that as the number of moles of gas increases, the pressure also increases, and vice versa.

5. Can the ideal gas law be applied to real gases?

No, the ideal gas law is only applicable to ideal gases, which do not exist in real life. Real gases have volume and interact with each other, unlike ideal gases that have negligible volume and do not interact. However, the ideal gas law can be used as an approximation for real gases under certain conditions.

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