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12 Questions around this concept.
A volume cylinder is filled with 1 mol of gas at room temperature (300 K). The molecular diameter of , and its root mean square speed are found to be 0.3 nm and 200 m/s respectively. What is the average collision rate (per second) for an molecule?
The number of air molecules in is increased from . The ratio of collision frequency of air molecules before and after the increase in the number respectively is :
The mean free path of molecules of a certain gas at STP is 1500d, where d is the diameter of the gas molecules. While maintaining the standard pressure, the mean free path of the molecules at 373 K is approximately :
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The mean free path of molecules of a gas,(radius ) is inversely proportional to
Mean Free Path -
On the basis of kinetic theory of gases, it is assumed that the molecules of a gas are continuously colliding against each other. So, the distance travelled by a gas molecule between any two successive collisions is known as free path.
There are assumption for this theory that during two successive collisions, a molecule of a gas moves in a straight line with constant velocity. Now, let us discuss the formula of mean free path -
Let be the distance travelled by a gas molecule during n collisions respectively, then the mean free path of a gas molecule is defined as -
Here, is the mean free path.
It can also be written as -
Now, let us take d = Diameter of the molecule,
N = Number of molecules per unit volume.
Also, we know that, PV = nRT
So, Number of moles per unit volume =
Also we know that number of molecules per unit mole =
So, the number of molecules in 'n' moles = nNA
So the number of molecules per unit volume is
So,
If all the other molecules are not at rest then,
Now, if and m = mass of each molecule then we can write -
So,
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