What is the equation for calculating molecular flux for a gas?

In summary, the molecular flux of argon gas, with a molar mass of 18 g/mol, density of 0.73 kg/m3, and temperature of 300 K, is 3.6×10^27 collisions/m^2s. This can be calculated using the equation flux = .25*(N/V)*√(8kT/(\pim)), where N/V is the number density of molecules, which can be found by dividing the given mass density by the mass of a single molecule.
  • #1
Erubus
22
0

Homework Statement


What is the molecular flux of argon gas, molar mass 18 g/mol, with density 0.73 kg/m3 and temperature 300 K? Answer: 3.6×10^27 collisions/m^2s

Homework Equations


I actually have no idea


The Attempt at a Solution


I can't find any reference to molecular flux in my notes or 2 physics textbooks, an equation would be appreciated.
 
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  • #3
Thank you for the link. If I read it correctly, flux = .25*(N/V)*√(8kT/([itex]\pi[/itex]m)

however, the density in the problem is given in kg/m^3 while the equation calls for the density based on the number of molecules, which is not given. It's probably an algebra problem now, but I'm also unsure with what to do with the given molar mass.
 
  • #4
Erubus said:
Thank you for the link. If I read it correctly, flux = .25*(N/V)*√(8kT/([itex]\pi[/itex]m)

however, the density in the problem is given in kg/m^3 while the equation calls for the density based on the number of molecules, which is not given. It's probably an algebra problem now, but I'm also unsure with what to do with the given molar mass.

It is easy to get the number density of molecules from the mass density and molar mass.
Molar mass is 18 g/mol=0.018 kg/mol. 1 mol gas contains NA (Avogadro Number) molecules, so the mass of a single molecule is 0.018/NA kg.
The mass density is 0.73 kg/m3, so the mass of 1 m3 gas is 0.73 kg. How many molecule is it ?

ehild
 
  • #5
Thanks, I got it now.
 

FAQ: What is the equation for calculating molecular flux for a gas?

What is the molecular flux of a gas?

The molecular flux of a gas is a measure of the number of molecules that pass through a given area per unit time. It is a measure of the rate at which gas molecules move through a space.

How is the molecular flux of a gas calculated?

The molecular flux of a gas is calculated by multiplying the density of the gas, the average velocity of the gas molecules, and the cross-sectional area through which the molecules are passing.

What factors affect the molecular flux of a gas?

The molecular flux of a gas is affected by the temperature, pressure, and molecular weight of the gas. It is also influenced by the size and shape of the container through which the gas is passing.

Why is the molecular flux of a gas important in chemistry?

The molecular flux of a gas is important in chemistry because it helps us understand and predict the behavior of gases in different conditions. It is also useful in studying gas diffusion and gas reactions.

How is the molecular flux of a gas related to the kinetic theory of gases?

The kinetic theory of gases states that gas molecules are in constant random motion and collide with each other and the walls of their container. The molecular flux of a gas is a measure of this motion and collision behavior, and it can be used to calculate other properties of gases, such as pressure and temperature.

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