Intermixing of two or more gases in available space is called diffusion. Diffusion of gas from high pressure to low pressure through an orifice is called effusion. The rate of effusion is : $r = \frac{PA}{\sqrt{2 πRTm}}$
A = Area of cross-section of orifice; P = Pressure of gas filled in the cylinder
T = Absolute temperature;
R = Universal gas constant
m = Molar mass of the gas
Effusion time of a gas is directly proportional to the square root of molar mass,
$\frac{t_{effuse} A}{t_{effus} B} = \sqrt{\frac{m_{A}}{m_{B}}}$ .
Rate of diffusion/effusion is experimentally measured by number of moles of gas or volume of gas diffused per unit time or distance travelled by the gas molecules per unit time.

Question

Intermixing of two or more gases in available space is called diffusion. Diffusion of gas from high pressure to low pressure through an orifice is called effusion. The rate of effusion is : $r = \frac{PA}{\sqrt{2 πRTm}}$
A = Area of cross-section of orifice; P = Pressure of gas filled in the cylinder
T = Absolute temperature;
R = Universal gas constant
m = Molar mass of the gas
Effusion time of a gas is directly proportional to the square root of molar mass,
$\frac{t_{effuse} A}{t_{effus} B} = \sqrt{\frac{m_{A}}{m_{B}}}$ .
Rate of diffusion/effusion is experimentally measured by number of moles of gas or volume of gas diffused per unit time or distance travelled by the gas molecules per unit time.

Accepted Answer

Diffusion and EffusionConcise reference with definitions, governing rate law, and Graham’s law relations.DiffusionIntermixing of two or more gases within available space.EffusionEscape of a gas from high pressure to low pressure through a tiny orifice. Rate of Effusion$ r=\dfrac{P\,A}{\sqrt{2\pi R T\, M}} $Symbols: $A$ area of orifice, $P$ gas pressure in the vessel, $T$ absolute temperature, $R$ universal gas constant, $M$ molar mass of the gas.Graham’s Law ConsequencesAt fixed $P, A, T$: $ r \propto \dfrac{1}{\sqrt{M}} $$ \dfrac{r_A}{r_B}=\sqrt{\dfrac{M_B}{M_A}} $Time to effuse a fixed amount: $ t \propto \sqrt{M} $$ \dfrac{t_A}{t_B}=\sqrt{\dfrac{M_A}{M_B}} $Experimental rate can be measured as moles or volume per unit time, or as molecular distance per unit time.

Best Courses for You

Detailed Solution

Diffusion and Effusion

Diffusion

Effusion

Rate of Effusion

Graham’s Law Consequences

courses

Get Expert Academic Guidance – Connect with a Counselor Today!

best study material, now at your finger tips!

download the app

Download the App